Category: Cold War French Prototypes

Spähpanzer 1C

SP. 1C., German turret. Illustration by Rolan Reboso

France/Federal Republic of Germany (1955?-1961)
Anti-Tank Reconnaissance Vehicle – 1 to 2 Prototypes Built

With the formation of the Bundeswehr in 1955, the new army of West Germany, a decision was made to acquire small tracked armored reconnaissance vehicles for use in the so-called Panzeraufklärungstruppe (Armored reconnaissance troop). The Schützenpanzer (Kurz), somewhat loosely translated as Infantry Fighting vehicle (Short), was born.

The Schützenpanzer was offered by the French company Hotchkiss-Brandt, which was unable to sell the design to the French in sufficient numbers due to budgetary constraints. The reconnaissance vehicle was offered as a family, ranging from infantry fighting vehicles to ambulances. Among the vehicles offered was a reconnaissance tank destroyer, which would be known as the Spähpanzer 1C (Reconnaissance tank 1C) or SP. 1C for short. This vehicle was interesting enough for the German staff to take the concept further and to let the German company Rheinmetall design a turret which matched German requirements. In the end, technical difficulties and the decreasing effectiveness of the chosen 90 mm gun caused the project to be closed.

The SP. 1C at the Museum of Military Technology in Koblenz.
Source: Spähpanzerjäger SP.I.C. Hotchkiss 90mm | 270862 | Flickr

The Founding of the Bundeswehr

Following the end of the Second World War, the defeated German Reich was divided into four occupation zones. As a result of the Potsdam Conference which took place from July to August 1945, France, Great Britain, and the United States occupied West Germany and the Soviet Union occupied East Germany. The four occupying powers decreed on August 30th, 1945, under Order no. 1, that the German Army was dissolved, with full dissolution of the armed forces under Law no. 8 on November 30th, 1945.

In the years following the occupation of Germany, a large string of events would open the door to German rearmament. The Cold War would slowly start as a result of the Soviet spread of communism through satellite states, the Truman Doctrine, the Berlin Blockade of 1948-1949, the detonation of the first Soviet atomic bomb, the formation of the separate West and East German states, the formation of NATO, the communist victory in the Chinese Civil War, and the Korean War from 1950 to 1953.

The Bundesrepublik Deutschland (Federal Republic of Germany, commonly known as West Germany) was founded on May 23rd, 1949. With the beginning of the Korean War a year later, a large group of ex-Wehrmacht officers met at the Himmerod Abbey to discuss the formation of a new West German Army. In 1951, the Bundesgrenzschutz (BGS) was formed as a lightly armed police force to patrol the West German border with the Soviet-aligned states.

Eventually, after a failed European Defence Community which attempted to put all the European Armies under a single overarching command structure, Germany was invited to NATO and joined on May 5th, 1955. On June 7th, 1955, the West German Federal Ministry of Defense was formed and, on November 12th, the Bundeswehr was created with the enlistment of its first 101 volunteers.

The Panzeraufklärungstruppe

With the formation of the Bundeswehr, a new reconnaissance force had to be rebuilt and reintegrated within the new West German Army units. NATO considered that a war with the Soviet Union would involve significant clashes of armored combat units. As a result, more divisions received an armored reconnaissance battalion, as they were integrated into Grenadier divisions as well. The expectation that the troops would have to fight for reconnaissance led to the integration of the M41 Walker Bulldog into the reconnaissance units.

The first Bundeswehr structure, in use from 1956 to 1958, called for 5 heavy reconnaissance squads with two M41s each, 11 light reconnaissance squads with 2 Bren Carriers each, a headquarters, and a supply company.

The battalion structure of a reconnaissance battalion within a tank division.
Source: Heeresstruktur 1 (1956–1958) – Die goldgelben Seiten (pzaufkl.de)

The second Bundeswehr structure, which was in use from 1959 to 1970, would initially struggle with what it actually wanted to achieve. The units were initially to receive 8 reconnaissance squads of 2 M41s each, 10 light reconnaissance squads with 2 SPz Kurz each, and 3 heavy squads were created, of which 2 received 2 M41s and 1 received an M41 and an IFV for radio. These new reconnaissance battalions and companies were so understrength that the units were not capable of performing combat missions according to a study of the Panzertruppenschule (Tank troop School).

By 1961, an additional heavy company was added to the understrength units, increasing the manpower of a reconnaissance battalion from about 287 men to almost 900. The increase was so significant that the reconnaissance battalions were on par with other battalions and were almost renamed to Panzerkavallerie-Bataillone (Armored Cavalry Battalions). The increase would cause the reconnaissance troops to be somewhat incorrectly deployed as either delaying or even offensive troops in practice maneuvers, besides their main reconnaissance tasks.

The 1961 restructure required a headquarters, 8 heavy squads with 2 M41s and 1 SPz Kurz each, 8 light squads with 2 SPz Kurz each, 2 infantry platoons with 9 SPz Kurz each, 2 armored platoons with 6 M41s each, a mortar platoon, and an Engineer platoon. The M41s would be replaced in 1965 by either the Leopard 1 or the M48 Patton after the Ru 251 light tank project had been canceled. The SPz Kurz would keep on serving into the third Bundeswehr structure until 1976, when it was replaced by the wheeled Luchs reconnaissance vehicle.

The 1961 restructured reconnaissance battalion.
Source: Heeresstruktur 2 (1959–1970) – Die goldgelben Seiten (pzaufkl.de)

The Schützenpanzer (Kurz)

The story of the Schützenpanzer (Kurz), from now on called SPz Kurz, began all the way back in 1946. The French company SEAM came up with a general purpose light tracked vehicle for the French airborne troops. The French airborne troops would eventually request such a vehicle and the French Ministry of Defense transferred the requirements to DEFA for study. DEFA would contact SEAM, Hotchkiss, and AMX to come forward with a proposal and evaluated them on August 11th, 1947. The SEAM and Hotchkiss proposals were selected and the companies were contracted to build prototypes. Eventually, Hotchkiss was chosen as the winner. At some point, the protection requirements increased and the airdrop capability of the vehicles became less important.

The SEAM prototype carried an 81 mm mortar.
Source: Les Véhicules blindés français, 1945-1977 (Bibliothèque ÉPA) by Pierre Touzin, 1978

Hotchkiss built prototypes of both cargo carriers and troop transport versions, known as CC 2-52 and TT 6-52 respectively. The vehicles were tested in France, North and South Africa, and the United States, after which the vehicle received favorable recommendations in 1952. A number of redesigns were incorporated, like a new Talbot/Hotchkiss engine instead of the original Ford engine. In total, the French ordered and built around 100 pre-series vehicles, but, due to the conflict in Indochina and later the Algerian War, full-scale mass production was unfeasible for the French Army.

The TT6-52 prototype, note the suspension already resembling that of the SPz Kurz.
Source: Les Véhicules blindés français, 1945-1977 (Bibliothèque ÉPA) by Pierre Touzin, 1978

This was where the newly founded Bundeswehr came in. The Germans were looking for a new vehicle to equip their reconnaissance units with and, in September 1955, the Cargo and APC versions were presented to the German Officials. The subsequent trials were promising enough for the Germans to order the Cargo version and to request 5 additional types to be designed. These were an Infantry fight vehicle, an 81 mm mortar carrier, an observation vehicle, a radar carrier, and an armored ambulance.

The combat weight of the vehicles was increased from 7 to 8.4 tonnes, the amount of road wheels was increased from 8 to 10, and the armor shape was redesigned. In practice, the vehicles were completely redesigned from the original basis to meet German requirements. Production began in 1958 with a total production run of 2,374 vehicles between 1958 and 1962, with the vehicle serving all the way up to the 1980s in the radar configuration.

An SPz Kurz Typ 11-2 armed with a 20 mm autocannon.
Source: https://forum.warthunder.com/index.php?/topic/530477-sch%C3%BCtzenpanzer-spz-11-2-kurz/

The French SP. 1C

Supposedly, the SP. 1C was presented to the Germans somewhere in 1955 as a Spähpanzerjäger (reconnaissance tank hunter/destroyer), but the vehicle shown with the French turret was clearly altered for German requirements as it already had 10 road wheels. Thus, either the Germans were quite quick in handing over new requirements and the French then built adjusted prototypes in just 3 months, including a one-off tank destroyer variant which the Germans did not seem to have initially asked for, or the date provided in sourcing is incorrect.

The French SP. 1C carrying an early version of the H-90 turret and armed with the French D921 90 mm cannon.
Source: Jagdpanzer der Bundeswehr

The Jagdpanzer der Bundeswehr book claims that the German officials were presented with the tank destroyer vehicle in 1955, but that, after tests, it was determined that Rheinmetall should redesign the turret in 1957. It seems much more likely that the vehicle was actually built somewhere around 1956-1957 and then tested.

The French proposal was essentially a Schützenpanzer (Kurz) redesigned to accommodate the turret and the increased weight of the vehicle. The SP. 1C carried a H-90 like turret, closely resembling that of the AML-90. The vehicle had a height of 2.07 m, used a 90 mm DEFA D921 gun as main armament and an unspecified coaxial 7.5 mm machine gun. It carried 50 rounds of 90 mm and 2400 rounds of machine gun ammunition. The vehicle was crewed by the driver, a gunner, and a commander/loader. The main gun could fire a HEAT (High Explosive Anti-Tank) round with a penetration of 320 mm (12.6 inch) flat and a muzzle velocity of 800 m/s, granting an effective range of 1500 meters.

These changes resulted in the vehicle’s weight increasing from 8.2 to 9.5 tonnes (9 to 10.5 US tons). This, in turn, required an uprated engine to 195 hp to maintain a power to weight ratio of 20.5 hp/tonnes. The transmission was upgraded as well, from 4 speeds forward to 5. Supposedly, the tank destroyer version also came with neutral steering.

When the vehicle was shown to the German Army staff, they were quite enthused with the notion of offering their reconnaissance units greater anti-tank protection. It was thus a likely possibility that the German staff considered the SP. 1C as a replacement for the M41 Walker Bulldogs which were, at that point, to be used as reconnaissance tanks. It is also a possibility that they simply wanted to add or replace a vehicle with an SP. 1C in the Schützenpanzer units to strengthen the light reconnaissance squads or to field dedicated tank hunter squads complementary to the existing structure. In the end, the H-90 turret was too cramped for German requirements and, in 1957, Rheinmetall was ordered to design a turret of their own for the potential Spähpanzerjäger.

A sketch of the SP. 1C from a French brochure.
Source: Châtellerault archives, photographed by Colasix

The German SP. 1C

Rheinmetall initiated the development of a new turret at the request of the Bundeswehr. The new turret incorporated a number of fundamental changes, most notably the Belgian 90 mm Mecar gun instead of the French 90 mm D921. Why this decision was made is unknown, but it is a possibility that the French simply refused to export their gun without exporting the turret as well. This was, for example, the case when the Brazilians wanted to import the guns for their X1 program, but ended up buying the entire turret as well, just to remount the guns into locally developed turrets.

The 90 mm Mecar was a bit of an odd gun. Very little is known about it and the gun only seems to appear on Swiss projects. After World War 2, the Swiss made an anti-tank gun known as the Pak 57, which seems to use the same muzzle brake and ammunition. It is a possibility that the Swiss bought a license from the Belgians or imported them and then started making their own anti-tank guns and arming vehicles with them. In any case, the Belgian 90 mm Mecar ended up on the SP. 1C as the main armament.

The 90 mm Pak 57 from Switzerland with the characteristic muzzle brake of the Mecar 90 mm.
Source: PAK 57 mobil-01 – Pak 57 – Wikipedia

The Mecar gun was, without a doubt, worse all across the board compared to the French D921. It only had access to two types of ammunition at the time, HEAT and High Explosive (HE). It fired the ammunition at much slower muzzle velocities, reducing the effective range from 1.5 km (1640 yards) to 1 km (1090 yards) and making the gun less accurate. The penetration performance of the gun was also thought to have been worse, as the HEAT projectile weighed about 2.4 kg (5.3 lbs) compared to the 3.64 kg (8 lbs) of the French gun, but is listed in sourcing as having the same penetration.

The 90 mm Mecar ammunition with the HEAT round on the left and the HE round on the right at Koblenz Tank Museum.
Source: Granate_90_mm.JPG (2304×3072) (discordapp.com)

The prototype turret was designed out of mild steel and sported a taller and more spacious shape. It also offered a much larger gun shield. This made the German vehicle 2.39 m (7.8 feet) tall compared to the French 2.07 m (6.8 feet), and increased the weight from 9.5 to 10.2 tonnes (10.5 to 11.2 US tons). The turret was designed with a multi-loading device. This meant that the turret would have some form of a magazine system, not to be confused with an autoloader. The vehicle was delivered for testing in 1961.

The Rheinmetall turret with the Mecar gun.
Source: https://live.staticflickr.com/4317/35411514284_d7a00ae703_b.jpg

The multi-loading magazine system showed significant deficiencies and the gun used was already becoming outdated in the 1960s for the European theater. Due to the vehicle weighing 10.2 tonnes, which the drive train could handle, the suspension was on the edge of being overloaded. It is, however, interesting to note that the Koblenz museum lists the weight at 9.5 tonnes instead, while Rolf Hilmes lists it at 10.2 tonnes. It is unknown why this discrepancy exists, but considering the increased turret size, it is unlikely the weight stayed the same.

The overloaded suspension meant that no upgrade in armament could be carried out and that any weight increase would likely lead to intensive wear on the suspension system. The lack of armor and limited gun performance at range also meant that the vehicle could only properly carry out its tank destroying tasks from prepared ambushes, and would most likely be destroyed in any other scenario if it faced an armored opponent. Due to these deficiencies, the SP. 1C was rejected by the Bundeswehr and never entered service.

The SP. 1C in detail

Considering the range of specifications of the French SP. 1C and the German SP. 1C are quite similar, both will be included in the technical description. The French SP. 1C weighed 9.5 tonnes (10.5 US tons) and was 4.42 m (14.5 feet) long without the gun forward and 4.90 m (16 feet) with the gun included. It was 2.3 m (7.5 feet) wide and 2.07 m (6.8 feet) tall. The SP. 1C had a crew of three, consisting of the commander/loader (turret left), gunner (turret right), and the driver (front hull left side).

The German SP. 1C weighed 10.2 tonnes (11.2 US tons) (or 9.5 tonnes according to Koblenz) and, considering the caliber lengths of the Mecar and D921 gun were almost the same, would have likely had fairly similar length dimensions compared to the French vehicle. The width was also the same, but the height was increased to 2.39 m (7.8 feet). The German SP. 1C had a similar crew layout except that the gunner might also have been the commander instead of the commander also being the loader.

Side angle of the SP. 1C at Koblenz.
Source: Англо-немецкий разведчик (livejournal.com)

Hull

Both the French and German SP. 1C hulls were practically the same. The hull was armored with a 10 mm (0.4 inch) upper front plate inclined at 74° from vertical and a lower front plate of 15 mm (0.6 inch) inclined at 28° from vertical. The driver’s frontal plate with the bulge was 10 mm thick. The sides were 8 mm (0.3 inch) thick inclined at 23° from vertical, with the rear being 8 mm thick as well and an inclination ranging from 19° to 31° from vertical. The top was 15 mm thick and the floor ranged from 15 mm to 8 mm at the rear.

The SP. 1C had two sets of light blocks, one on each side of the upper front plate. These blocks included a headlight, a black-out light and an orange light (presumably turn signals). In between the light blocks was the gun lock with behind it a large removable plate to give access to the engine and transmission but also the driver’s compartment. In essence, the entire front plate could be taken off.

The upper front plate, note the plate sections that could be removed.
Source: https://yuripasholok.livejournal.com/10635162.html

The driver’s position was clearly distinguished by the large bulge welded on the upper front plate. This bulge contained the mountings for three periscopes and a rotating sliding hatch for the driver. The driver steered with two tiller bars and had to manually shift gears. A fire extinguisher was located to the front right of the driver. The clutch pedal was located on the left, the brake on the right, and the accelerator pedal to the right of the brake pedal. The instrument panel was located to the left of the driver. The driver also had access to a floor hatch underneath the seat if needed.

The driver’s position on the SP. 1C.
Source: https://yuripasholok.livejournal.com/10635162.html

The engine was located to the right of the driver. The engine air intake was located on the top hull on the front right. Behind the left light block was a siren and on either side of the upper front plate would have been side mirrors. At the front right side plate was the exhaust for the engine and behind it were belts to enable attachments of stowage. On the left side plates were attachments for pioneer tools.

The rear had two rear lights combined with turn signals on each side. The upper rear plate offered two hatches for unknown purposes. On top of one of the hatches was a stowage system for either spare tracks or perhaps the convoy driving cross. The lower front plate featured a towing hook.

The side and rear.
Source: https://yuripasholok.livejournal.com/10635162.html

Mobility

The SP. 1C was powered by a 195 hp Talbot/Hotchkiss 6-cylinder in-line petrol engine. This was effectively the same engine as on the original SPz Kürz, with the exception that the cylinders were bored out to increase the cylinder volume from 4.678 l to 4.977 l. This increased the horsepower from 164 to 195 and the torque from 324 to 353 Nm (238 ft lbs to 260 ft lbs). The engine was coupled to a 5 speed forward and 1 speed reverse transmission, in contrast to the 4 speed forward transmission of the standard vehicle.

Gear	Gear ratio	Speed at 3900 rpm
1	7.7	7.5 km/h
2	4.12	14 km/h
3	2.45	23.6 km/h
4	1.48	39.2 km/h
5	1	58 km/h
Reverse	7.1	8.3 km/h

This gave the vehicle a maximum speed of 58 km/h (36 mph) and 8.3 km/h (5.15 mph) in reverse. The power to weight ratio for the French variant would have been 20.5 hp/tonne and 19.1 hp/tonnes for the German SP. 1C. The vehicle had a 355 l (93 US gallons) fuel tank, of which 85 l (22.5 US gallons) was put away for reserves. This gave the vehicle an operational range of about 360 km (224 miles).

The Talbot/Hotchkiss engine.
Source: Chatellerault archives by Colasix

The SP. 1C used a torsion bar suspension with 5 road wheels on each side. The suspension system was reinforced to better handle the increased weight of the design on the French proposal. The suspension utilized shock absorbers and rubber stops to limit the travel of the suspension arms. The drive sprocket was located at the front and the idler wheel was at the rear. The total of 98 track links of each track were further supported by 3 guide wheels. The tracks were 308 mm (12.1 inch) wide and had a total on-ground track length of 2.38 m (7.8 feet). This gave the SP. 1C a ground pressure of 0.65 kg/cm2 for the French vehicle and 0.69 kg/cm2 for the German vehicle.

Turrets

The SP. 1C had two separate turrets available. One was an early form of the French H-90 turret which would be used on the AML-90 and the other was a turret developed by Rheinmetall at the request of the Bundeswehr. With the German turret also came a new main armament which seems to have been inferior to the French gun.

The reasons for choosing another main armament is unknown, but it can be noted that, when the Brazilians tried to buy 90 mm guns from the French in 1974, they had to buy both the turrets and guns in a single package. It is possible that this policy was already in place as early as the late 1950s, which forced the Germans to find a different gun.

The French Turret

The French turret was armored with 15 mm of welded steel plates at the front and had a decreasing thickness of 15 to 10 mm on the side from front to rear. The rear had a thickness of 10 mm and the top had a thickness of 8 mm. This armor would provide protection against small caliber rounds.

The French turret, note the different muzzle brake.
Source: Jagdpanzer der Bundeswehr

The commander/loader, positioned on the left side of the turret, had 4 periscopes available and the gunner on the right as well, with a single main firing periscope available in front of him totaling to 5 periscopes. It is unclear if the gunner had access to an emergency direct fire telescope fixed to the right of the main gun, in the gun mantlet. In the middle of the turret top, behind the commander and gunner hatches, was the outlet for the ventilation system. The coaxial machine gun was located on the left side of the main gun. The antenna of the radio was located behind the gunner and attached to the rear side plate. Two smoke launchers were mounted on each of the rear of the turret side plates, for a total of four.

It is unknown how far the interior of this early H-90 turret was similar to the H-90 production turret. As such, the following information is provided in case the layout was almost exactly the same. The turret stored 24 rounds of 90 mm ammunition, of which 12 rounds on the left side of the turret bustle and another 12 rounds in two 6 round-revolver style magazines behind the gunner and the commander. The turrets stored 2,400 rounds (12 boxes) for the 7.5 mm coaxial machine gun, of which at least 9 were stored in a magazine in the frontal part of the turret basket floor. The turret had a gun depression of -8° and an elevation of +15°.

The ammunition stowage in the turret bustle of an AML-90.
Source: http://www.primeportal.net/tanks/david_lueck/aml-90/

A schematic interior view of the HS-90 turret.
Source: Panhard Armored Car Enthusiasts’ manual

The German turret

The German turret developed by Rheinmetall was manufactured out of mild steel, as opposed to armor grade steel. The German turret has a reasonable amount of unknown details. Some of this has been a result of the lack of interior picture of the turret or lack of measurements. As the Koblenz Museum, where the SP. 1C is preserved, is still closed, this information cannot yet be obtained.

The armor was likely somewhat similar to the French turret and is not thought to have offered more than protection against small arms. Interestingly, Rolf Hilmes claims the armor of the German SP. 1C was 20 mm, which could refer to the thickness of the gun shield. This could have theoretically barely provided the front with protection against .50 cal machine gun fire.

The German turret was octagonal shaped and welded. The vehicle had a distinct gun shield with a direct fire telescope on the right side of the gun and the coaxial machine gun to the left. On both sides of the gun shield were two protrusions with small sliding hatches, the purpose of which is unknown. The gunner, located on the right, had 4 periscopes and what seems to be a main telescope for the main gun on the right of the front periscope.

An excellent view of the SP. 1C turret, with the very large plate on the middle top and the protrusion next to the gun shield.
Source: https://live.staticflickr.com/4317/35411514284_d7a00ae703_b.jpg

The commander/loader on the left only had two periscopes pointing to the side of the vehicle. This seems strange and might suggest that, in the German turret, the gunner was also the commander and the loader only had loading duties, in contrast to the French layout. Both crew men had relatively small hatches. The middle of the turret top was occupied by a very large plate. It seems that the purpose of this plate was to help facilitate the magazine loading system of the main gun. If the gun was depressed past a certain point, the magazine system would move upwards to still accommodate loading the gun. This moving plate was located from the gun shield to the rear of the turret and had hinge attachments on the front. The turret had a gun depression of -8° and an elevation of +15°.

The two rear side plates had three smoke launchers each and the rear plate had two smoke launchers and an antenna attachment. The rear plate also had a small brass plate with the writing: Turm 2 Sp Kurz, Flußstahlausführing, Rh.-Nr.WK-G2 (Turret 2 Sp Short, mild steel version, Rh.-Nr.WK-G2). This could suggest that Rheinmetall developed two turrets or that the initial French turret was considered as turret 1.

The small brass plate.
Source: https://yuripasholok.livejournal.com/10635162.html

Nothing is known of the turret interior. It is assumed that a very large portion of the turret interior would be occupied by the magazine loading system of the vehicle. According to the information sign in front of the SP. 1C at Koblenz, the magazine loading system could house an astonishing 18 main rounds. Sadly, as pictures are non-existent, this cannot be confirmed visually, nor is it known if the prototype even retained its magazine loading system to begin with.

An excellent view of the turret rear. Note the smoke discharger layout, the middle antenna and the small brass plate below.
Source: https://yuripasholok.livejournal.com/10635162.html

Armament

The SP. 1C used both the French 90 mm D921 and the Belgian 90 mm Mecar gun. Of these guns, the French gun was both superior in performance and ammunition load-out. The Mecar gun only offered High Explosive Anti-Tank (HEAT) and High Explosive (HE) ammunition. The French gun could also fire smoke and canister ammunition.

90 mm D921
Round	Capability	Effective range	Velocity
HEAT (High Explosive Anti-Tank)	320 mm (12.6 inch) flat at any range.	1,500 meters (1,640 yards)	750 m/s
HE (High Explosive)	Lethal radius of 15 meters (16 yards)	1,500 meters (1,640 yards)	650 m/s
White Phosphorus – Smoke	50 meters wide smoke screen for 20 to 30 seconds	1,500 meters (1,640 yards)	750 m/s
HEAT-TP (High Explosive Anti-Tank – Training Projectile)	Inert (no explosive filling)	1,500 meters (1,640 yards)	750 m/s

The Belgian gun was inferior performance wise in both muzzle velocity and effective range. The Belgian HEAT round only had a muzzle velocity of 630 m/s against 750 m/s of the French gun. This made the Mecar gun less accurate and gave it an effective range of 1200 m (1,310 yards) opposed to 1500 m (1,640 yards). The HE round was even more problematic due to the 338 m/s muzzle velocity, opposed to the French 650 m/s.

90 mm Mecar
Round	Capability	Effective range	Velocity
HEAT (High Explosive Anti-Tank)	320 mm (12.6 inch) flat at any range.	1,200 meters (1,310 yards)	630 m/s
HE (High Explosive)	Lethal radius of 15 meters (16 yards)	–	338 m/s

The French vehicle had a total of 50 rounds of 90 mm ammunition, of which an estimated 24 could be found in the turret, while the German version was said to stow around 40, of which potentially 18 in the magazine loading system. The French SP. 1C also came with a 7.5 mm machine gun as opposed to the MG 42 for the German variant.

Fate

In the end, the SP. 1C’s already overloaded chassis was bound to cause reliability issues in any long term operation of the vehicle. The main armament’s suitability was falling off rapidly by the 1960s against increasingly heavy Soviet material. The magazine loading system, which was perhaps the vehicle’s only redeeming factor, also proved to have been lacking during tests. This system was perhaps one of the few features which could have made the SP. 1C deadly in ambushes due to the potentially rapid loading times. As such, the SP. 1C could only effectively contribute to the anti-armor capability of the reconnaissance troops from covered positions in an ambush. For these reasons, the SP. 1C was rejected by the Bundeswehr and the prototype remains at the Koblenz Tank Museum.

A Mystery

While researching the SP. 1C, the writer found a picture of a vehicle on a Quora thread which suspiciously looks like some form of SP. 1C. The turret seems to be a much lower profile variant of the current turret and overall much more simplified. The turret almost seems like a mock-up or a home-built. It is unclear if this turret was perhaps the turret 1 prototype from Rheinmetall or just a hobby construction. Any information regarding the vehicle’s origin and owner would be much appreciated.

The SP. 1C image posted in the Quora thread.
Source: What is the cheapest military tank? – Quora

Conclusion

The SP. 1C was an interesting yet faulty concept. Had the vehicle been developed much earlier and perhaps not as a weapon against the increasingly heavily armored Soviet tanks, the results might have been different. The SP. 1C simply pushed the boundaries of its own capabilities too far and with technical systems that proved to be faulty. By the 1960s, it also became clear that the Leopard 1 would be replacing the M41 Walker Bulldogs in the reconnaissance units, which had a much higher fighting chance against its Soviet counterparts. The SP. 1C remains as an interesting light tank and an attempt to take the SPz Kurz family full circle by offering a dedicated anti-tank vehicle.

SP. 1C., German turret. Illustration by Rolan Reboso

SP. 1C., French turret. Illustration by Rolan Reboso

Specifications	French SP. 1C	German SP. 1C
Dimensions (L-W-H)	4.9 x 2.3 x 2.07 m (16 x 7.5 x 6.8 ft)	4.9 x 2.3 x 2.39 m (16 x 7.5 x 7.8 ft)
Total weight, battle-ready	9.5 tonnes (10.5 US tons)	10.2 tonnes (11.2 US tons)
Crew	3 (driver, gunner, commander/loader)	3 (driver, commander?/gunner, loader)
Engine	Talbot/Hotchkiss 6-cylinder in-line 195 hp petrol	Talbot/Hotchkiss 6-cylinder in-line 195 hp petrol
Speed	58 km/h ( mph)	58 km/h ( mph)
Range	360 km ( mi)	360 km ( mi)
Power to weight ratio	20.5 hp/tonne	19.1 hp/tonne
Suspension	Torsion bar	Torsion bar
Transmission gearing	5 forward – 1 reverse	5 forward – 1 reverse
Fuel capacity	355 l (93 US gallons)	355 l (93 US gallons)
Armament	Primary: 90 mm DEFA D921 Coaxial: 1 x 7,5 mm	Primary: 90 mm Mecar Coaxial: 1 x 7.62 mm MG42
Elevation and traverse	15° elevation 8° depression	15° elevation 8° depression
Ammunition capacity	50	Around 40
Armor	Hull: 15 mm lower front plate 10 mm upper front plate 8 mm sides and rear Turret: 15 to 10 mm	Hull: 15 mm lower front plate 10 mm upper front plate 8 mm sides and rear
Production	1 prototype	1 prototype

Sources

Kanonen/Raketen-Jagdpanzer der Bundeswehr – Peter Blume
Jagdpanzer der Bundeswehr – Rolf Hilmes
Schützenpanzer – Frank Köhler
Schützenpanzer kurz, Hotchkiss/ lang, HS 30 – Peter Blume
Bundeswehr und Ausrüstung – Thomas Haslinger
Koblenz Tank Museum
Chatellerault archives by Colasix
https://pzaufkl.de/

Cold War French Prototypes

Batignolles-Châtillon 12t

Batignolles-Châtillon 12t 1947 with interleaved suspension. Illustration by Brian Gaydos.

France (1947-1951)
Light Tank – 1 Prototype Built

France was, in the 1930s, a major tank-producing nation in Europe, second only to the Soviet Union and Germany in output. This productive industry, which, while designing tanks that often followed archaic requirements, used modern technology, saw its abilities to continue evolving and producing new vehicles mutilated by the German invasion of France and the Low Countries in the spring of 1940. As part of the Compiègne armistice imposed on France, production and design of new tanks was strictly forbidden, and only a few designs, some covert and some designed for potential use by Axis nations, would prop up in the following years – most based on pre-existing technology and hulls which could not match newer vehicles developed by other countries.

France was liberated in 1944, with the new government, at this point under De Gaulle, adamant in its goal to recover French independence and self-sufficiency. Getting the military industry back up was one of several aspects of this policy. It was in this context that, in 1947, the French army would establish requirements for an airborne, 12-tonne light tank armed with a high-velocity 75 mm anti-tank gun with anti-armor capacities; a fairly ambitious prospect. Three manufacturers were approached to design such a vehicle, or at least its chassis: the state workshop of AMX, the old Mediterranean shipyard of FCM, and lastly, the locomotive-turned-tanks manufacturer Batignolle-Châtillons.

A Resurgent Tank Industry

Before the outbreak of the Second World War, France was one of the largest tank manufacturers on the European continent and in the world, second only to two nations which far outmatched France’s population and industrial potential, Germany and the Soviet Union. The defeat of France in 1940, of which inadequate tank designs and use is one of many culprits, led to the country being occupied all the way to the summer of 1944. Outside of a few covert projects undertaken by a secretive organisation of the Vichy regime, the CDM (Camouflage du Matériel/Equipment Camouflage), new developments were practically stopped. The few new designs considered, such as the SARL 42, largely took the basis of elements existing or already being studied in 1940. France was wholefully unable to keep up with the technological advancements that countries with intact or at least functioning tank industries were developing and fielding during the war.

The first ‘new’ French armored fighting vehicle to enter production following the liberation of France, the Panhard 178B, was, in practice, the combination of a hull and gun already in existence in 1940 with a new turret. Source: char-français

Following France’s liberation by the Western Allies and FFI (Forces Françaises de l’Intérieur – English: French Forces of the Interior) uprisings in the summer of 1944, the new French leadership, still under Charles de Gaulle, was very keen on ensuring France’s independence to the best of their capacities. This included resuming work on indigenous armaments projects as swiftly as possible. The first of the post-war designs would be worked on as early as 1944, largely based on pre-war designs and concepts or salvaged German equipment, adapted as best as possible to still be suitable for use in a postwar context. The two best examples of these first attempts at kicking a tank industry back on its feet, the ARL 44 and Panhard 178B, were neither revolutionary nor even truly modern vehicles, yet one could hardly say they were not successful in their roles. The ARL heavy tank was the first true French tank manufactured post-war, helping the industrials get back into shape, while the Panhard 178B not only did the same for France’s most important wheeled armored fighting vehicles manufacturer, Panhard, but also provided an indigenous vehicle to supplement the plethora of American and British types used to maintain a French colonial empire now at the brink of collapse, particularly in Indochina.

Work on these vehicles was well underway by the summer of 1946. The Panhard 178B had entered mass-production, while the ARL 44 at least had a functional vehicle completed, though it would eventually be a far fetch from the production standard. Following this, more ambitious and truly new vehicles could begin to be considered.

It is in this context that, in September 1946, the French EMA (Etat Major des Armées – English: Army General Staff) requested DEFA (Direction des études et fabrications d’armement – English: Armament Studies and Manufacturing Direction), the organism in charge of managing the production of French military equipment, to oversee the creation of an air-transportable reconnaissance vehicle which would weigh 12 tonnes at most. Within the French Army’s technical services, there was a preference for a light tank which would feature heavy armament for its weight, making it able to engage enemy armor, rather than be a more passive, lightly-armed reconnaissance vehicle. Mobility was also an important factor to compensate for the necessarily weak armor such a vehicle would possess. As such, one could describe the vehicle which was envisioned as the combination of a reconnaissance vehicle, a light tank and a tank destroyer. Furthermore, as early as January 1947, additional variants, in the shape of an anti-aircraft vehicle and a self-propelled artillery piece, which were to share a common chassis with the light tank, were being considered.

At this point, DEFA offered the STA (Service Technique des Armées – English: Technical Service of the Armies) the outline of three concepts. All would share an oscillating turret, a concept previously given only minimal attention, but which was viewed as potentially a good option to save weight. The concepts varied in the muzzle velocity of their 75 mm main guns, the goals being 600, 878, and 920 m/s. STA expressed interest in an oscillating turret fitted with the higher muzzle velocity main gun, a concept it accepted on 10th February 1947. By late February, the concept had been passed on to EMA, which set requirements for a 12 tonnes vehicle with a 75 mm gun that could reach at least 850 m/s, and optimally 1,100 m/s. At least 40 rounds were to be stowed within the vehicle. Fuel capacity was to be at least 300 l.

After these few months of back and forth and development of the concept by French Army structures, the requirements were eventually passed on to three manufacturers on 24th April 1947. These were the Atelier Mécaniques d’issy-Les-Moulineaux (AMX, English: Issy-Les-Moulineaux Mechanical Workshop), the Compagnie générale de Construction de locomotives Batignolles-Châtillon (English: Batignolles-Châtillon general locomotives Construction Company) and the Forges et Chantiers de la Méditerranée (English: Forges and Shipyards of the Mediterranean). All three had designed armored vehicles pre-war, though Batignolles-Châtillon did not have any production vehicles to its name. AMX had designed the R40, an evolution of the R35, and taken part in manufacturing the B1 Bis, while FCM had also had its own B1 Bis manufacturing chain as well as its own FCM 36 and FCM 2C designs.

The manufacturers were only requested to design the hull, as well as eventually the casemate for the self-propelled artillery version. The turrets for the light tank as well as anti-aircraft vehicles were to be procured from separate manufacturers.

A French Tank on a German-Style Suspension

The first known plans of the Batignolles-Châtillon 12t are dated from 31st October 1947. These show a light tank with a more centrally-mounted turret, rather than the rear-mounted turret that was present on both the FCM 12t and the AMX-12t.

A side profile view of the interleaved-suspension 12t proposal. This variant differed very significantly from all other proposals of the program, not only because of its interleaved road wheels, but also because of its use of a centrally-mounted turret and rear engine. Source: char-français

A top view of the 1947 design. With a driver to the front left and an engine to the rear, this was arguably the closest to classic tank architecture out of all the 12t proposals, but it also looked significantly larger than the other vehicles. Source: char-français

An approximately 1.80 m tall crewman standing aside the interleaved version of the 12t. In height at least, the vehicle was fairly low. Source: char-français.

The vehicle had a quite long hull for a light tank, with 5.050 m from the front to the rear of the track run. The height of the hull was of 1.240 m, and the width of the hull itself was 1.630 m, to which each 385 mm-wide set of track should be added, making the vehicle 2.4 m wide in total.

The vehicle’s suspension appears to have used, in this shape, a front-mounted sprocket and a rear-mounted idler. The most peculiar aspect of the suspension, though, would likely have been the road wheels. This early design used a set of seven interleaving road wheels on each side, a suspension-type typically present in late-war German designs, from which the French took heavy inspiration. The four outward wheels, each separated by a middle one, were doubled with another wheel on the inner side of the vehicle, while the middle wheels were single, but noticeably thicker. There was 2.8 m between the center of the first and last road wheel. The center of the first roadwheel was 1.140 m from the front of the track run, and the center of the last roadwheel 1.110 m from the rear of the track run.

Three unfortunately very blurry views of the schematics of the interleaved Batignolles-Châtillon 12T with the SAMM anti-aircraft turret. This turret was integrated into the design work from the very start. Source: Châtellerault archives

Set of plans of the artillery version of the interleaved road wheels Batignolles-Châtillon 12t. Source: Châtellerault archives, provided by Colasix

This 1947 set of plans show both the oscillating 75 mm-armed turret, still retaining the shorter gun that likely would have been the one with a 850 m/s velocity, and the anti-aircraft turret armed with a set of four MG 151/20 20 mm autocannons. The schematics of the 75 mm-armed vehicle, in particular, are very detailed when it comes to the internal arrangement of the hull. There were also schematics for an artillery version, which retained the centrally mounted armament; this vehicle used a casemate, with a small turret, likely some sort of commander’s cupola, armed with a 20mm autocannon.

The driver of the vehicle would have been seated at the front left, with seemingly the gearbox to his right and the transmission to his front. The combat compartment was to his immediate rear, with the commander sitting to the left of the gun and the gunner to its right. Hull ammunition stowage would be present immediately in front of them, at the front of the combat compartment and turret, where 26 rounds would be located. A further 8 rounds were present at the front left of the turret basket, and seemingly 4 rounds to the rear of the turret, in front of the engine compartment, giving a total of 38 rounds of ammunition stowage in addition to the 12 rounds already present in the two revolver-type magazines of the turret.

This detailed planview of the interleaved 12t’s arrangement shows, in great detail, the interior of the vehicle and features such as the ammunition stowage, but also the interleaving of the road wheels, doubled outward wheels and double-thickness inward wheels. Source: char-français

A profile cutaway view of the same proposal showing the driver with the head out of his hatch, as expected when driving outside of a combat zone. Source: char-français

This cutaway view of the interleaved 12t, looking towards the rear, shows not only the engine block in great detail, but also the interleaved roadwheel and how the central roadwheel is two times thicker than the outward ones. Source: char-français

This cutaway view of the front of the vehicle, looking towards the front, shows the position of the driver and transmission. Source: char-français

Though this version of the Batignolles-Châtillon 12t project is the first to be known, and appears in a quite detailed set of plans, the vehicle which would move further and reach prototype stage was vastly different from this one. It appears that the interleaved road wheels configuration was dropped early on and that the vehicle was deeply redesigned, with the overall dimensions of the hulls and tracks, for example, being changed as well. This was likely in an effort to reduce weight, seeing as the Batignolles-Châtillon project appeared, at this time, to have a larger volume than the FCM and AMX projects, in addition to interleaving road wheels which would typically add quite a lot of additional weight. Whether or not the vehicle would be able to remain below 12 tonnes was quite questionable.

Continuing Evolutions toward a Prototype

The set of projects from all three companies was approved by the STA on 24th May 1948 and cleared to continue. It appears that mock-ups were constructed by all manufacturers in the following months. However, the Batignolles-Châtillon project appears to have, around this point, started to accumulate delays. A formal order for a prototype appears to only have been passed on 14th February 1949, as order 18.211 – the same month the FCM prototype was completed. By December 1949, the FCM and AMX prototypes were compared to each other for a pre-production order of five vehicles. The AMX won and was picked for a pre-production run of five vehicles – basically setting it on the road to becoming the adopted vehicle. The Batignolles-Châtillon project did not take part in this comparison as a prototype was not yet completed.

Batignolles-Châtillon would only formally present the 12t vehicle in its facilities of Nantes on 13th June 1950. This was a very late date, and while AMX’s project would only formally be adopted in early 1951, it was clear at this point that it was picked in all but name – the Batignolles-Châtillon arrived too late to realistically have a chance to be picked. Trials were nonetheless run with the vehicle.

Design

Hull

The design of the Batignolles-Châtillon 12t light tank in its final form is known mostly thanks to a set of plans dated from June of 1950. It appears that general ideas of the tank’s design had existed since about two years – we already know of schematics of a Batignolles-Châtillon 12t artillery vehicle dated from March 1948, which featured a similar suspension.

The March 1948 artillery Bat-Chat 12t schematics. This design already features the large individual road wheels and rear casemate/turret of the later design. Source: Châtellerault archives, provided by Colasix

June 1950 side profile of the Batignolles-Châtillon 12t light tank. The vehicle’s arrangement has little to nothing in common with the previous interleaved design. Source: Châtellerault archives

As the two other proposals born out of the same program, the Batignolles-Châtillon vehicle had opted for a rear-mounted turret, an entire change of configuration in comparison to the earlier interleaving road wheels design. The hull had a length of 4.38 m, and a height of 1.280 m at the top of the driver’s position. With the gun, the length would reach a higher 6.472 m, and the height 2.170 m.

The 12t’s hull had been designed to be as thin and compact as possible, with the track width being, in comparison, designed to be fairly large. The idea was that the hull would be as thin as the turret ring diameter, powertrain and driver’s post would realistically fit in, and these mechanical organs would be designed to be as compact as possible. In practice, the turret even had some moderate extrusions, as it would otherwise have had overhang from the side of the hull. The Batignolles-Châtillon’s vehicle hull was 1.46 m wide, with 100 mm separating this hull from the 370 mm-wide pair of tracks. Overall, the vehicle would have a width of 2.4 m, at this point identical to the earlier design. Ground clearance was 31.5 cm.

A front view of the vehicle from the same set of plans; the overhang of the turret ring is noticeable. Source: char-français

A plan view from the same set of plans. Source: Châtellerault archives

The hull was made of laminated steel plates assembled together by welding. The frontal protection of the hull was to be equivalent to 40 mm at a flat angle. In practice, this translated into the upper front plates being 25 mm thick angled at 15° and 27° degrees from the vertical. The lower front plate was 25 mm thick as well, angled 75° from the vertical. The front bottom was 15 mm thick, angled at 20°, while the rest of the vehicle appeared to have had a 10 mm-thick bottom. All three rear plates were 19 mm-thick, angled at 25°, 50° and 80° respectively. The roof was 10 mm thick, and the sides 20 mm. These values are taken from the trials report from 1951. The 1950 schematics are different in this regard, with the front reported to be 31 mm at its thickest point.

The armor layout of the 12t, from the October of 1951 trials report. It appears that, in June 1950, it was still planned to have a 31 mm thick frontal hull, though other aspects of the hull armor appear to have been identical between both documents. Source: Châtellerault archives

The driver of the Batignolles-Châtillon 12t was installed to the front left of the vehicle. He sat on a seat with two positions: an upper position would have the driver’s head stick out from the driver’s post, when driving outside of combat. In combat, the seat would be lowered. The driver would then observe the outside from a periscope. To his front, the commands at his disposal would be, from left to right, a direction lever for the left track, a handbrake, hand-controlled clutch, followed by foot pedals in the same order as in a civilian car: the brakes, the clutch pedal and the accelerator. The gear-selecting lever, direction lever for the right track, and a reverser lever for the transmission were located towards the driver’s front right. The gear-selective lever was preselective, as would be found in a typical car, with the driving elements of the vehicle had been designed to be as similar as a classic road vehicle. The hand-clutch command would only be used when starting up the vehicle, with the foot clutch pedal taking its place when the vehicle was running. The instrument panel would be located just right of the driver’s head. The oil circuit for the gearbox was installed over the foot pedals, with the oil filter to their right, behind the gear selector from the driver’s point of view. Brakes, gear and direction were all hydraulic Lockheed controls.

A top view of the driver’s post on the prototype, looking towards the right. The driver’s seat, gear selector, direction lever, and inversor toggle can all be seen. Source: Châtellerault archives

The 12t driver post’s dashboard, to the right of the lever. The gear selector on the bottom left can be seen. Source: Châtellerault archives

A photo of the driver’s post taken from the rear towards the front, showing the handbrake, clutch, and pedals. Source: Châtellerault archives

A view of the same driver’s post from slightly higher. The various pedals, and above them the gearbox oil circuits, with the oil filter to the right can be seen. Source: Châtellerault archives

Ammunition stowage within the hull at this point would have been of 22 rounds, a considerable reduction in comparison to the previous model.

Power train

The power train of the vehicle was located to the right of the driver, separated by a bulkhead. It was put together in a block which was designed so that the armor plating protecting it could easily be disassembled, in order to hasten maintenance or replacement work. This engine block sat on four mounts designed to prevent vibrations.

A view of the ventilation within the Batignolles-Châtillon 12t’s engine block. Source: Châtellerault archives

The vehicle appears to have been planned and tested with different engines. The first engine used in the Batignolles-Châtillon 12t was a Mathis 18 GZ 00 petrol aviation engine. This was a 4-stroke, 7-cylinders arranged in a ‘V’ , 6,827 litre engine. The vehicle later received a Mathis Type 8 GZ, which was an 8-cylinder engine. In order to reduce weight, it was decided that the vehicle would use air cooling. Air would enter from grills at the front of the engine block, go through two oil radiators (one for the engine and one for the gearbox), the cylinders, and be exhausted by a fan through another grill. The first engine and clutch mechanism had a weight of 365 kg together, including 20 l of oil. Later, the 8-cylinder engine had a weight of 327 kg, but it is unclear whether that was just the engine itself or also included the clutch mechanism and oil.

A front view of the Batignolles-Châtillon 12t prototype, showing the large air entry for the engine block. Source: Châtellerault archives

Clutch was assured by a singular disc. The Batignolles-Châtillon 12t used a gearbox with six gears. The first gear would multiply engine rotations by 22.5; the second by 6.23, third by 3.79, fourth by 2.38, fifth by 1.53, with the sixth rotating at the same rate as the engine. Direction was assured by a triple differential going through the gearbox. The gearbox was also relatively light, with merely 300 kg, including oiling systems.

The vehicle’s fuel tanks had a capacity of 300 litres and were located towards the rear of the vehicle, behind the turret ring.

A rear view of the Batignolles-Châtillon 12t prototype. The exhaust can be seen to the right; the port on the lower left is likely to fill the rear fuel tank. Source: Châtellerault archives

In general, the powertrain of the Batignolles-Châtillon 12t was remarkable in the compactness and lightweight it offered. When breaking down how the volume was shared inside the vehicle, the engine block, including the transmission, comprised 30% of the internal space; the driver’s position comprised 20%, the fuel tanks 10%, and the combat compartment behind and around the turret ring the remaining 40%.

Suspension

This finalized version of the 12t had completely changed the whole suspension and mechanical arrangement of the vehicle, which no longer had anything in common with the previous interleaving road wheels.

A profile view of the Batignolles-Châtillon 12t prototype. The vehicle features two fairly large return rollers and two large shock absorbers. Source: Châtellerault archives

A close-up on two roadwheels of the Batignolles-Châtillon 12t prototype. Source: Châtellerault archives

The vehicle had now moved to using a torsion bar suspension with four large road wheels, with a diameter of 600 mm. Two large pneumatic shock absorbers were present on each side of the suspension, one at the front and one at the rear, each linked to two road wheels and guaranteeing a very smooth ride. These road wheels were not evenly spaced; the front one’s center was 830 mm from the second’s, which was 750 mm from the third’s, itself 690 mm from the fourth’s. The vehicle featured a large raised front sprocket, its center 778 mm from the first roadwheel’s, and a much smaller rear idler, its center 670 mm from the last roadwheel’s. Overall, the length between the centers of the first and last roadwheel was of 2,270 mm.

A photo of the 12t’s two-part track link. Source: Châtellerault Archives

The same track link and the track pin. Source: Châtellerault archives

The vehicle’s tracks were 370 mm wide with a 135 mm pitch. The ground pressure they would apply was 0.685 kg/cm² on soft soil, and 10.2 kg/cm² on hard soil.

Turrets

The Batignolles-Châtillon 12t hull was designed to interchangeably mount two different turrets.

The first was the Fives-Lilles FL 4. This was an oscillating turret, the first known French post-war development in the field. It had been designed to mount a high-velocity 75 mm anti-tank gun. On the FCM 12t, it first appeared with a ‘short gun’ that was likely the projected weapon firing at 850 m/s, but the weapon that appears to have been durably retained would instead be the ‘1,000 m/s’ 75 mm gun, which would eventually be standardized as the 75 mm SA 50. The FL 4 oscillating turret allowed for an elevation of 13° and a depression of -6°.

This 75 mm SA 50 featured two armor-piercing shells. Both weighed 21 kg, with the projectile being 6.4 kg, and had a muzzle velocity of 1,000 m/s. The first, the POT modèle 1951/POT-51A (Perforant Ogive Traceur – English: Armor-Piercing Capped Tracer/ APC-T), would penetrate 110 mm at 90° and 60 mm at 30°, at a range of a kilometer. The second, PCOT modèle 1951/PCOT-51P (Perforant Coiffé Ogive Traceur – English: Armor-Piercing Capped Ballistic Cap Tracer / APCBC-T), would penetrate 170 mm at 90° and 40 mm at 30° at the same range of a kilometer. Lastly, a high-explosive shell existed, which had the same velocity but was slightly lighter (20.6 kg), with a projectile weight of 6.2 kg and an unknown explosive charge.

An AMX pre-production vehicle with the longer-barrelled 1,000 m/s 75 mm gun. The FL 4 turret which would have been mounted on the FCM 12t would have been closer to this one, rather than the one present in the September 1948 schematics. Source: flickr

The FL 4 was a two-man turret, with the commander to the left of the gun and the gunner to the right. The reason for this reduced crew was that the turret used a bustle autoloader system, with two 6-round revolver magazines located in the rear bustle of the turret. This solution took less space than a manual loader and, as such, helped lighten the vehicle, which was necessary for the air-transportability requirement. A total of 40 75 mm rounds would be stowed within the vehicle. The turret had a coaxial MAC 31 7.5 mm machine gun, with 1,050 rounds of ammunition stored. Frontal protection for the turret would be equivalent to 40 mm, while the sides and presumably rear were 16 mm thick and the roof 10 mm.

Observation devices included seven periscopes in the observation cupola for the commander, while the gunner could use an observation and targeting periscope as well as a gun sight. The turret featured an American SCR-508 radio, which would be shared by all versions of the vehicle. With the FL 4 turret, the vehicle was to be 2.170 m high.

The other turret which was to be featured in the Batignolles-Châtillon 12t was the SAMM S232 anti-aircraft turret. It was designed by the Société d’Application des Machines Motrices (English: Motor Machines Application Society) and was designed to be mounted on each of the three 12t light tanks projects. The first prototype was completed in May 1949.

A close-up of a SAMM S232 turret, this particular example mounted on an AMX-13 pre-production hull. Source: Les véhicules blindés Français 1944-1977

This turret’s armament consisted of four MG 151/20 20 mm autocannons of German origin. It was the standard 20 mm autocannon for Luftwaffe aircraft for most of the war. It fired 20×82 mm cartridges at a rate of up to 750 rounds per minute, with a muzzle velocity of up to 785 m/s. MG 151s, both in the 15 and 20 mm versions, were fairly widely used in post-war France, including in armored vehicles designs.

The S232 turret was 1.020 m high. As it was designed for anti-aircraft use, it had a high maximum elevation of 80°, with a more moderate depression of -5°. The turret used cast construction and was fully enclosed. The front had the same 40 mm of effective thickness as the FL 4, as did the sides at 16 mm. Likely in order to improve resistance to strafing, the roof armor was quite significantly thicker at 30 mm.

Weight Distribution and Expected Performances

The distribution of the weight in the 12t was to consist in:

2,180 kg of hull armor
3,630 kg from the suspension and wheels
365 kg from the engine, clutch, liaison between these, and 20 litre oil tank
300 kg for the gearbox and transmission including a 20 litre oil tank
70 kg for the radiator
55 kg for the controls
240 kg for the batteries
380 kg for miscellaneous elements such as the separations between the compartments, electric group and wiring, stowage, etc.
4,200 kg for the turret, including the two crewmen and 18 rounds of ammunition
80 kg from the driver
260 kg of fuel
300 kg from the 22 rounds of ammunition stored inside the hull

This would result in a vehicle weighing in at 12,060 kg, and as such almost perfectly equal to the expected 12 tonnes. When subtracting the two turret crewmen, all fuel and all ammunition, the weight would be of 11,340 kg; without the driver, it would logically be reduced to an empty weight of 11,260 kg.

The expected performances from this vehicle were to be a maximum speed of 3 km/h on the first gear, 12 on the second, 19 on the third, 31 on the fourth, 48 on the fifth, and finally, an impressive 73 km/h on the sixth gear. The average cruise speed on road was expected to be 40 km/h. Considering the reverse speed was assured by a gear inversor, the tank would be expected to reach the same speeds in reverse.

It was expected that, at ⅗ of the maximum engine power, the 300 litres fuel tanks would allow for 6 hours of continuous running, or a practical range of about 240 km. The vehicle was expected to climb a 70% slope, and be able to go down a slope of a similar degree while remaining controllable.

Artillery Version

In addition to the hull which would be used in the tank and anti-aircraft versions of the vehicle, Batignolles-Châtillon also designed an artillery version armed with a 105 mm in a fixed casemate. This version is known from a set of plans dated from June 1950, and it is not known if a version using the interleaved suspension design of the hull has ever been worked on.

A profile view of the artillery version; the hull was largely the same, but the turret was entirely replaced by a new fixed casemate. Source: Châtellerault archives

The casemate featured a sloped frontal plate and square sides; the front plate would have been 26 mm thick, with the sides and rear 20 mm thick. The casemate expanded beyond the rest of the hull and over the tracks, with a total width equal to the vehicle with tracks at 2.4 m, in order to increase the internal space allocated to the crew. At 2.175 m high, the vehicle would be only 5 mm higher than the tank version.

A front view of the artillery vehicle, showing the considerable overhang of the casemate over the tracks, necessary in order to increase internal space. Source: Châtellerault archives

A top view of the artillery version. The gun extended very little beyond the hull. Source: Châtellerault archives

The reason for a quite large casemate being needed was both the size of the 105 mm AU 50 gun and of the crew needed to operate it. The gun had a length of 3.096 m from the end of the muzzle brake to the breech. As such, it only had a very limited overhang in front of the hull, reducing the length of the vehicle to a mere 4.663 m. To operate it at a sufficient rate of fire, seeing as there was no autoloader, the casemate crew would be of four – a commander, a gunner, and two loaders – in comparison to the two-man crew of the tank version’s turret. Forty 105 mm rounds would be stowed within this casemate. Depression was reduced to a mere -3°, but elevation was a lot higher, at +67°, to allow for indirect fire.

Impressively, the additional weight was kept to a minimum in comparison to the tank. The vehicle’s weight without casemate crew, fuel and ammunition was noticeably lighter, at 10,730 kg, and even with the full crew, fuel and ammunition load, weight was expected to only reach 12,230 kg – in other words, only 170 kg more than the tank configuration. The engine, transmission and suspension were left unmodified, and the mobility was expected to largely be the same. Ground pressure was to be raised by a mere 10 grams per cm² on soft soil, reaching 0.695 kg/cm².

Prototype and Trials

The Batignolles-Châtillon light tank prototype was formally presented in June of 1950 in Nantes. Trials began at Satory in January of 1951. The vehicle was transferred to the STA in May 1951, with trials continuing until they were stopped in September.

A top view of the Batignolles-Châtillon 12t prototype without the turret test-weight present, with the turret ring empty and fully visible. A fueling port can also be seen on the rear right, as well as the ventilator on the front right. Source: Châtellerault archives

A side view of the same prototype, this time with the large, more than 3.5 tonne weight which was used to simulate a turret. Source: Châtellerault archives

In comparison to the vehicle on the plans, the prototype received another engine, a Mathis Type 8 GZ 8-cylinders aviation engine with 6,927 l. Its horsepower output is not known. The hull was not fitted with a turret, and instead received a 3,539 kg weight. The hull, without crew, ammunition or fuel, was weighed at 8,119 kg, giving the trial vehicle a total weight of 11,658 kg. It had a ground pressure of 0.640 kg/cm² on soft soil. The prototype also featured two return rollers, which were perhaps considered but not present on previous schematics.

The experimentation of the prototype was conducted by AMX, with a trials report produced in October of 1951. Sadly, only parts of this report have surfaced, and how exactly the Batignolles-Châtillon vehicle fared is unknown. The vehicle would, in all likelihood, have been the fastest out of all the 12t prototypes, and it appears it may have retained a fairly moderate weight even with the turret and full fuel and ammunition load. However, by this point, the AMX vehicle, which was highly satisfactory, was already adopted and entering production, and so it was highly unlikely the Batignolles-Châtillon vehicle would be ordered even if very high performing.

Conclusion – Too Late to the Party

The Batignolles-Châtillon 12t is notable in that it basically had two vastly different configurations during its life as a design, starting as a relatively large light tank with a centrally-mounted turret that was deeply modified, or likely even redesigned from the ground up, as a smaller and likely lighter vehicle with a turret mounted to the rear. The specifics of the design appeared to grant it an impressive maximum speed for the era, as well as a likely smooth drive. However, the vehicle was at least a year late, if not more, in comparison to the AMX and FCM vehicles, and with the AMX-12t already being a clear favorite by the time the Batignolles-Châtillon 12t was even completed, it had pretty much no chance of being adopted.

In recent years, the fairly obscure 12t has seen a regain of popularity in online circles, likely due to the popularity of the ‘Batignolles-Châtillon’ name due to the inclusion of first the 25t, and later some 12t-type vehicles in Wargaming’s popular online game ‘World of Tanks’. Two 12t-based vehicles exist in World of Tanks, the base Batignolles-Châtillon 12t and the ‘Bourrasque’ premium. Both are based on the interleaved road wheels, central-turret design, but while the 12t vehicle itself appears to at least somewhat try to replicate a realistic version of that configuration, the ‘Bourrasque’ is a fictional design combining this hull dated from 1947 to a modified version of the late 1970s TS 90 turret – one of the most egregious example of fake tanks present in Wargaming’s game.

Batignolles-Châtillon 12t 1947 with interleaved suspension. Illustration by Brian Gaydos.

Batignolles-Châtillon 12t 1947 with the SAMM anti-aircraft turret and interleaved suspension. Illustration by Brian Gaydos.

Batignolles-Châtillon 12t prototype. Illustration by Brian Gaydos.

Batignolles-Châtillon 12t 1950. Illustration by Brian Gaydos.

Batignolles-Châtillon 12t 1950 with the SAMM anti-aircraft turret. Illustration by Brian Gaydos.

Batignolles-Châtillon 12t 1950 artillery version. Illustration by Brian Gaydos.

1947 interleaved road wheels design Specifications
Hull dimensions (L x w x h)	5.05 x 2.40 x 1.24 m
Transmission	Front
Suspension	Torsion bars with interleaved road wheels
Road wheels	7
Track width	38.5 cm
Crew	3 (Driver, Gunner, Commander/Radioman)
Main Armament	75 mm gun (future 75 mm SA 50)/ 4x MG 151/20 autocannons (AA variant)
Ammunition stowage	12 already loaded + 38 rounds
Elevation & depression	+13° to -6°
Loading mechanism	2 x revolving automatic loading system with 6 rounds each
Secondary Armament	Coaxial 7.5 mm MAC 31 machine gun
7.5mm ammunition stowage	1,050 rounds
Hull Armor	40 mm equivalent (front), 20 mm (sides and rear), 10 mm (floor), uncertain but likely 10 mm (roof)
Turret Armor	40 mm equivalent (front), 16 mm (sides and rear), 10 mm (roof)
Produced	0

Finalized design (1950) Specifications
Dimensions (L x w x h)	6.472 x 2.40 x 2.17 m
Empty weight	11,26 0kg
Loaded weight	12,060 kg
Engine	Mathis 18 GZ 00 aviation engine
Fuel
Cylinders	V7, 7-cylinder 6,827 L
Horsepower output	210 hp
Power-to-weight ratio in hp/tonne	17.5
Gearbox	6 forward speed with inversor
Maximum speed	73 km/h
Cruise speed	40 km/h
Fuel tanks	300 L
Range	240 km
Autonomy at ⅗ of maximum engine power	6 hours of continuous operations
Transmission	Front
Suspension	Torsion bars
Road wheels	4
Track width	370mm
Track pitch	135mm
Ground pressure	0.685 kg/cm² (soft soil) 10.2 kg/cm² (hard soil)
Crew
Main Armament	75 mm gun (future 75 mm SA 50)
Ammunition stowage	40 rounds
Elevation & depression	+13° to -6°
Loading mechanism	2 x revolving automatic loading system with 6 rounds each
Muzzle velocity	1,000 m/s
Maximum armor penetration at 1,000m	170 mm at 90°
Secondary Armament	Coaxial 7.5 mm MAC 31 machine gun
7.5mm ammunition stowage	1,050 rounds
Hull Armor	25 mm at 27° and 15° (upper front plate) 25 mm at 75° (mid-lower front plate) 15 mm at 20° (lower front plate) 15 mm (front floor) 10 mm (most of the floor) 19 mm at 25, 50, and 80° (lower, mid, and higher rear plates) 20 mm (sides) 10 mm (roof)
Turret Armor	40 mm equivalent (front), 16 mm (sides and rear), 10 mm (roof)
Produced	0

Artillery version (1950) Specifications
Dimensions (L x w x h)	4.663 m x 2.40 x 2.175 m
Empty weight	10,650 kg
Loaded weight	12,230 kg
Engine	Mathis 18 GZ 00 aviation engine
Fuel	Petrol
Cylinders	V7, 7-cylinder, 6,827 L
Horsepower output	210 hp
Power-to-weight ratio in hp/tonne	17.2
Gearbox	6 forward speed with inversor
Maximum speed	73 km/h
Cruise speed	40 km/h
Fuel tanks	300 L
Range	240 km
Autonomy at ⅗ of maximum engine power	6 hours of continuous operations
Transmission	Front
Suspension	Torsion bars
Road wheels	4
Track width	370 mm
Track pitch	135 mm
Ground pressure	0.695 kg/cm² (soft soil) 10.2 kg/cm² (hard soil)
Crew	5 (Driver, Gunner, Commander/Radioman, two loaders)
Main Armament	105 mm AU 50
Ammunition stowage	40 rounds
Elevation & depression	-3° to +67°
Muzzle velocity	570 m/s
Hull Armor	25 mm at 27° and 15° (upper front plate) 25 mm at 75° (mid-lower front plate) 15 mm at 20° (lower front plate) 15 mm (front floor) 10 mm (most of the floor) 19 mm at 25, 50, and 80° (lower, mid, and higher rear plates) 10 mm (roof)
Casemate armor	26 mm sloped (front) 20 mm (sides and rear) Likely 10 mm (roof)
Produced	0

Test vehicle (1950-1951) Specifications
Dimensions (L x w x h)	6.472 x 2.40 x 2.17 m
Empty hull weight	8,119 kg
Additional weight	3,539 kg
Total weight without driver or fuel	11,658 kg
Engine	Type 8 GZ aviation engine
Cylinders	8-cylinder 6,927 L engine
Gearbox	6 forward speed with inversor
Fuel tanks	300 L
Transmission	Front
Suspension	Torsion bars
Road wheels	4
Track width	370 mm
Track pitch	135 mm
Ground pressure	0.640 kg/cm²
Crew	1 (driver)
Hull Armor	25 mm at 27° and 15° (upper front plate) 25 mm at 75° (mid-lower front plate) 15 mm at 20° (lower front plate) 15 mm (front floor) 10 mm (most of the floor) 19 mm at 25, 50 and 80° (lower, mid, and higher rear plates) 10 mm (roof)
Produced	1

Sources

Les véhicules blindés français 1945-1977, Pierre Touzin, éditions EPA, 1978
Char-français: http://www.chars-francais.net/2015/index.php/2-archives/engins/2642-1947-batignolles-12
French military archives of Châtellerault, made available by Colasix:
Service Historique de la Défense, Châtellerault 503 3H1 27
Service Historique de la Défense, Châtellerault 326 3H1 23
Service Historique de la Défense, Châtellerault 343 3H1 41

Cold War French Prototypes

Giacomini Tank

Giacomini's patent tank, illustration by Relan Reboso.

France (1956)
Tank – Patent Only

Post-World War Two Europe was a continent rich in the legacy of the war. A legacy which took the form of an abundance of tanks, both in the form of legacy leftovers of the war, and a ready supply of new tanks from Britain (Centurion) or the United States (M47). The only thing matching this ready supply of tanks was an absence in the availability of foreign capital with which to purchase new tanks.

Yet new tanks were needed. The French had the remains of an empire to defend and there was also the very real threat of the powerful Soviet Union to the east, occupying much of what was left of Eastern Europe and Germany, along, of course, with the emergence of nuclear weapons.

Into this strategic mess of bankruptcy, an attempt to reassert an old order, and a new and assertive European land power, came the unassuming George Giacomini. In 1956, Giacomini submitted his concept for what was needed: a modern tank for these new and most dangerous times; a multiturretted, front-engined giant capable of preparing its own defenses. Whilst his design was not practical and was never built, it serves to illustrate one of the few ideas for new battle tanks in Europe at this time.

Novelty

The point of patents is to protect an element of novelty. Ergo, something new to an existing item or product or system. The novelty at play in Giacomini’s design was not strictly just the tank, although it is an odd design for the time in its own right. Instead, the novelty was that this tank should be equipped, as standard, with trench digging/earthmoving equipment with which it could provide its own defensive structure. The fact that he decided to show it on such an odd platform, one so out of keeping with the tank trends prevailing for in-service vehicles of the time, was perhaps the most novel aspect of the whole design.

The Man

Georges Giacomini is also an enigma. His location on the patent application was Bouches-de-Rhône, an area on the south coast of France, close to Italy, where there was a significant Italian population. His nationality is not given as ‘Citizen of the Republic of France’, but, instead, as a “residant en France” – in other words, merely living in France and not French.

The only additional clue is also a patent. In March 1974, a man called Georges Giacomini, a resident of ‘Quartier Bel-Air 13300 Salon de Provence’ applied for a patent in France for a type of power generator using water pressure. That patent was granted in 1975. This location is within the province known as Bouches-de-Rhône. Whoever he was, whatever his background or nationality, he appears to have remained in the area for some time and continued to put his mind to ideas of technology and engineering, even if his tank never left the patent office.

The Tank Described

Giacomini provides no dimensions for the tank, but it is clearly a large vehicle. Suspension consisted of 8 road wheels on each side supporting a high track run, presumably running on some return rollers under the side plates out of sight.

The engine and automotive elements which are undescribed would clearly be fitted into the front of the vehicle, leaving a space at the back on which to mount the turret with the primary armament.

Side elevation of Giacomini’s tank showing the rather large body, mini-turrets, and an awkwardly placed rear turret. The half-moon-shaped device on the front is the special digging attachment and the primary purpose of the entire patent.
Source: French Patent FR1151425
Note: image has been digitally cleaned by the author.

The body, large and cumbersome, is taller than most tanks, with the bulk of the hull rising above the level of the track run. The front of the tank is not sharply angled to meet the glacis but instead comes up vertically until it is level with the top of the tracks. After this vertical section it is followed by a short nose angled back at around 45º before the sloping glacis begins. This glacis extends back to a point level with around the second road wheel at around a 25º angle before meeting the flat top of the hull.

Immediately behind the intersection of the glacis with the hull top are a pair of small hemispherical turrets. Behind these mini turrets, the hull roof is flat covering an area under which can only be assumed to be the engine and other power components, vents, radiators, etcetera, needed to move the vehicle.

On the back half of the hull is a raised platform with a sloping front on which the main turret (carrying the primary armament) is mounted. This section is actually misdrawn in the plan view of the patent where the primary gun is shown in the plan-view as protruding from the front of the platform rather than the turret itself. The side elevation view is much clearer showing the gun attached to the turret instead.

Plan view of Giacomini’s tank showing the main gun redrawn to correctly show it attached to the primary turret rather than the raised platform.
Source: French Patent FR1151425
Note: image has been digitally cleaned and altered by the author.

The turret itself is of a well rounded form in plan view but which has vertical sides all round. The front slopes back from the rounded mantlet presenting a small and well shaped profile to an enemy vehicle. On top of the turret is a large square hatch and another square hatch is drawn on the rounded rear of the turret.

The back of the hull has the same 45º angled short ‘nose’ from the front, before becoming a vertical flat back plate. Over the vertical sides of the vehicle are a set of side skirts covering the running gear just just below the top of the road wheels.

It is onto these side skirts that the clever digging gear devised by Giacomini is attached.

Armament

Regarding the arrangement of the tank with its tall hull and mini turrets half-way down the length of the body, it is unclear if these turrets were just there for show in the patent, or if Giacomini genuinely thought these might be useful. Their placement certainly allows for depression of their guns down over the glacis to fire forwards, covering the blindspot which might otherwise be a problem in a rear-turreted tank, but Giacomini put the rear turret’s main gun so high up that it could itself depress to cover the same area. Quite what benefit these mini-turret guns could add is unclear. They are not drawn as some small gun either, like a machine gun, but something more akin to a small caliber cannon. As previously stated, the arrangement shows a vehicle with the engine and transmission-type components in the hull front and/or middle, so these turrets would potentially be crewless in order to save space inside for the machinery.

The gun in the primary turret is unusual in its own right. The curved mantlet is more than simply a protective cover over the front of the turret. Here, instead, the mantlet is also a mount for the gun itself. Formed in a circular shape, the mantlet is a letter ‘C’, with the breech of the gun attached to the base of the open face of the ‘C’ and then poking out through the back of the letter. With the trunnions, the bearings and point about which the whole piece rotates, in elevation mounted centrally within the ‘C’. The whole affair rotates as a wheel around a much larger arc of rotation than with a normal type of gun mounting, both in elevation and depression. Control of this rotation is done by means of a planetary gear affixed to the turret which engages with gearing on the mantlet to cause it to rotate up to “90 [degrees] with absolute accuracy”.

Side elevation of the primary armament in the turret on Giacomini’s tank showing the relative proportion of the armor in the almost circular mantlet with the gun attached to it in two places. A second gun is attached below the main gun. This method of mounting allows both guns to achieve a high angle of elevation.
Source: French Patent FR1151425
Note: image has been digitally cleaned by the author.

The patent clearly explains that the turret is expected to be able to rotate around a full 360º. With this gun mounting system as previously described, the vehicle is thus able to provide fire around a substantially wider area than a conventional vehicle. The primary gun is not identified or speculated about. However, the secondary gun is described and known to be an undisclosed type of heavy machine gun. This gun was not only for engaging targets in its own right but was also intended as an aid to aiming of the main gun.

Entrenching

The primary purpose of the patent, and rather overshadowed by the tank he provided as a carriage for it, was the earthmoving blade. This was no mere bulldozer blade. Such things had already been in widespread use for years, and Giacomini’s vision for an improvement was something quite different. Shaped in the manner of a half-moon in profile, his blade curved inwardly towards the vehicle unlike a conventional blade which curves away from the vehicle to act as a scoop.

Side elevation of Giacomini’s entrenching blade in use.
Source: French Patent FR1151425
Note: image has been digitally cleaned by the author.

The purpose of this earthmoving device was specifically for mobile and static use, something a normal type of blade could not do. In motion, the power of the vehicle could be used to push with the blade, but also, by dropping it, to scrape out an entrenchment for the vehicle.
When static, the same could still be done. I.e when the tank might have stopped to engage in combat it could deploy its entrenching device to build up earth or debris in front of the hull to help provide additional protection.

The way this worked was by virtue of the mounting system. On a conventional blade, it is usually attached to either mounts on the front of the tank, or onto pivots on the side and can be moved hydraulically. It operates just as a ‘pusher’ to move earth in front of it. On Giacomini’s design, the vehicle, even when stationary, could rotate the large mountings on the side skirts to lower the blade. The blade itself, mounted on a pair of horizontal tubes attached to that large mount could then propel the blade forwards as it gets dropped onto the ground, and then retract it back towards the vehicle to create a scrape in front of the vehicle. By repeating this extend/drop, retract and scrap technique several times the vehicle could thereby create a substantial berm in front of itself for protection.

Conclusion

The patent is surprisingly brief, at just 3 pages long. For such a complex device of earthmoving equipment, or the unusual gun mounting system, a longer description might normally be expected. In fact, he provides so much visual information in terms of the drawing of the tank and an unnecessary addition of those mini-turrets on the hull that it overshadows both of the really innovative elements and for no additional benefit.

As a tank, the design is certainly unusual. Front engine tanks were not new, there had been designs prior to Giacomini’s in 1954. Probably the most famous of these, and a vehicle with an equally hefty and brutalistic hull shape, was the German Maus. Giaocomini’s design of a tank is somewhat annoyingly vague on technical details despite him clearly having given some thought to layout and how a vehicle could work in combat. The ability to fire the tank’s main gun vertically and the ability to dig itself in were things nobody else had managed prior to that date, and yet those mini-turrets were a retrograde element in the design, adding no combat power and replacing them instead with added complexity, cost, crew, and weight.

As drawn and described the tank offered little for militaries. The lack of detail and the ‘regression’ to an earlier era of tanks with multiple turrets was unlikely to find interest. As such, the design stayed a patent and appears to have been quickly forgotten.

Giacomini’s patent tank, illustration by Relan Reboso.

Giacomini Tank Specifications Giacomini Tank
Crew	u/k
Dimensions	u/k
Armour	u/k
Armament	one primary gun and coaxial gun, two mini-turret
Engine	u/k
Speed	u/k

Sources

French Patent FR1151425, Disposif de terrassement adapte a un char de combat. Filed 14th June 1956, granted 19th August 1957, published 30th January 1958.

French Patent FR 7411006, Disposif generateur de puissance. Filed 26th March 1974, granted 24th October 1975.

Cold War French Prototypes

FCM 12t

France (1947-1952)
Light Tank – 1 Prototype Built

The Second World War left France’s tank industry in an uncertain state. One of Europe’s largest and most sophisticated tank manufacturers prior to the four year German occupation which mutilated France’s military industry while simultaneously very severely limiting design work on not only new tanks, but also engines and armaments. Whether France could recover and become a military-industrial powerhouse, or at least major player, was still uncertain.

It is in this context that, in 1947, the French Army would establish requirements for an airborne, 12-tonnes light tank armed with a high-velocity 75 mm anti-tank gun with anti-armor capacities, a fairly ambitious prospect. Three manufacturers were approached to design such a vehicle, or at least its chassis: the state workshop of AMX, the locomotive-turned-tank manufacturer Batignolle-Châtillon, and lastly, the old Mediterranean shipyard of Forges et Chantiers de la Méditerranée (FCM).

Ambitions from Ashes

Before the outbreak of the Second World War, France was one of the largest tank manufacturers on the European continent and in the world, second only to two nations which far outmatched France’s population and industrial potential, Germany and the Soviet Union. The defeat of France in 1940, of which inadequate tank designs and use is one of many culprits, led to the country being occupied all the way to the summer of 1944. Outside of a few covert projects undertaken by a secretive organisation of the Vichy regime, the CDM, new developments were practically stopped. The few new designs considered, such as the SARL 42, largely took the basis of elements existing or already being studied in 1940. France was wholefully unable to keep up with the technological advancements that countries with intact or at least functioning tank industries were developing and fielding during the war.

The first ‘new’ French armored fighting vehicle to enter production following the liberation of France, the Panhard 178B, was in practice the combination of a hull and gun already in existence in 1940 with a new turret. Source: char-français

Following France’s liberation by the Western Allies and FFI (Forces Françaises de l’Intérieur – ENG: French Forces of the Interior) uprisings in the summer of 1944, the new French leadership, still under Charles de Gaulle, was very keen on ensuring France’s independence to the best of their capacities. This included resuming work on indigenous armaments projects as swiftly as possible. The first of the post-war designs would be worked on as early as 1944, largely based on pre-war designs and concepts or salvaged German equipment, adapted as best as possible to still be suitable for use in a postwar context. The two best examples of these first attempts at kicking a tank industry back on its feet, the ARL 44 and Panhard 178B, were neither revolutionary nor even truly modern vehicles, yet one could hardly say they were not successful in their roles. The ARL heavy tank was the first true French tank manufactured post-war, helping the industrials get back into shape, while the Panhard 178B not only did the same for France’s most important wheeled armored fighting vehicles manufacturer, Panhard, but also provided an indigenous vehicle to supplement the plethora of American and British types used to maintain a French colonial empire now at the brink of collapse, particularly in Indochina.

It is in this context that, in September 1946, the French EMA (Etat Major des Armées – ENG: Army General Staff) requested DEFA (Direction des Études et Fabrications d’Armement – ENG: Armament Studies and Manufacturing Direction), the organism in charge of managing the production of French military equipment, to oversee the creation of an air-transportable reconnaissance vehicle which would weigh 12 tonnes at most. Within the French Army’s technical services, there was a preference for a light tank which would feature heavy armament for its weight, making it able to engage enemy armor, rather than be a more passive, lightly-armed reconnaissance vehicle. Mobility was also an important factor to compensate for the necessarily weak armor such a vehicle would possess. As such, one could describe the vehicle which was envisioned as the combination of a reconnaissance vehicle, a light tank and a tank destroyer. Furthermore, as early as January 1947, additional variants, in the shape of an anti-aircraft vehicle and a self-propelled artillery piece which were to share a common chassis with the light tank, were being considered.

At this point, DEFA offered the STA (Service Technique des Armées – ENG: Armies Technical Service) the outline of three concepts. All would share an oscillating turret, a concept previously given only minimal attention, but which was viewed as potentially a good option to save weight. The concepts varied in the muzzle velocity of their 75 mm main guns, the goals being 600, 878 and 920 m/s. The STA expressed interest in an oscillating turret fitted with the higher muzzle velocity main gun, a concept it accepted on 10th February 1947. By late February, the concept had been passed on to the EMA, which set requirements for a 12 tonnes vehicle with a 75 mm gun that could reach at least 850 m/s, and optimally 1,100 m/s. At least 40 rounds were to be stowed within the vehicle. Fuel capacity was to be at least 300 l.

Schematics of the FCM 12t dated from September 1948. The vehicle featured a 75 mm gun shorter than the high-velocity 75 mm SA 50 which would eventually be adopted, likely a representation of a gun with a muzzle velocity of about 850 m/s. Source: French military archives

After these few months of back and forth and development of the concept by French Army structures, the requirements were eventually passed on to three manufacturers on 24th April 1947. These were the Atelier Mécaniques d’issy-Les-Moulineaux (AMX, ENG: Issy-Les-Moulineaux Mechanical Workshop), the Compagnie générale de Construction de locomotives Batignolles-Châtillon (ENG: Batignolles-Châtillon general locomotives Construction Company) and the Forges et Chantiers de la Méditerranée (ENG: Forges and Shipyards of the Mediterranean). All three had designed armored vehicles pre-war, though Batignolles-Châtillon did not have any production vehicles to its name. AMX had designed the R40, an evolution of the R35, and taken part in manufacturing the B1 Bis, while FCM had also had its own B1 Bis manufacturing chain as well as its own FCM 36 and FCM 2C designs.

The set of projects from all three companies were approved by the STA on 24th May 1948 and cleared to continue. It appears that mock-ups were constructed by all manufacturers in the following months, though no views of the FCM mock-up appear to have survived. The known set of plans of the vehicle is dated from 4th September 1948 and is indicated as “revised after inspection of the mock-up”. It features a shorter version of the gun that would eventually be used within the FL 4 turret, the future 75 mm SA 50. By this point, the FCM project was estimated to weigh 11,360 kg in combat conditions, still a fair bit under the 12 tonnes limit. In the meantime, in July 1948, the industrial company of Fives-Lilles presented its mock-up of the FL 4 oscillating turret which was to be fitted into the 12 tonnes light tank vehicles.

The FCM project progressed further and a prototype hull was completed in February 1949. After trials in Toulon in March, it was presented to the French Army’s technical services in July, the same month as its competitor from AMX, and a whole 11 months before Batignolles-Châtillon would submit their own.

Design

The FCM 12t’s Hull

The hull designed by FCM used a rear turret and placed the driver and powertrain at the front, as did the other two 12t proposals. The total length of the hull was to be 4.485 m. Including the gun mounted in the FL 4 turret, the tank would be 6.570 m long. 3.875 m separated the center of the sprocket from the center of the idler. The tank was 2.080 m tall with the FL 4 turret, with the hull itself being 1.130 m tall. The vehicle was 2.4 m wide, though this could be raised to 2.5 m with a different set of tracks. The hull itself was 1.7 m wide, while the ground clearance was 30 cm.

The FCM hull used welded construction. This had been a staple of FCM back in the 1930s, when this was very much a novelty in French tank design, the FCM 36 light tank being the only French mass-produced welded tank. By the late 1940s however, the Second World War had demonstrated the advantages of welding over casting and particularly bolting or riveting, and what was once an FCM specialty was now pretty standard. An interesting feature of the FCM design was that the frontal section of the hull was designed to be easily removable. This included most of the major mechanical components save for the engine itself: the preselective gearbox, transmission, and drive sprockets could be swiftly taken out for maintenance or even to be quickly replaced in this fashion.

Front schematic view of the FCM 12t dated from September 1948. The front section of the hull containing all major mechanical components outside of the engine was designed for swift removal and replacement or repairs. Source: French military archives

The driver sat to the left of the hull front, while the engine was installed to the right. The FCM 12t used a front transmission and a rear idler. The driver would maneuver the vehicle using either a steering wheel or a unique lever. The drive sprockets were linked to hydraulic brakes the driver would operate using pedals. Each sprocket could be braked independently, which would allow rotating the tank by using the movement of a single track. The cutch was also assured by a pedal while the gearbox was operated by a lever. Acceleration was also assured by a pedal, which was also associated with a hand-operated command. Overall, the FCM 12t was noted to be practically identical to a car in how it was driven. The driver had a periscope for vision.

A top view of the FCM 12t. The front-right of the hull was taken by the large radiator grills, while the driver’s post slightly stuck out of the hull on the front right. Source: French military archives

The armor was “30 mm equivalent” on the frontal arc, apparently differing in actual thickness depending on each exact section to match with 30 mm of effective thickness. The sides were 20 mm thick while the floor was 10 mm. The roof was of unknown thickness, but likely 10 mm as well, seeing as that thickness was also the one of the roof of the FL 4 turret.

Powerplant and Suspension

The FCM 12t’s engine was a Mathis 8 G X 00 8-cylinders 6,560L gasoline engine. At the nominal rotation rate of 3,000 rounds per minute, it would provide 210 hp. The engine was water-cooled. 415 l of gasoline could be stored within the FCM 12t’s fuel tanks. The radiator’s tanks contained 35 l of water. The brakes had a total of 10 l of oil in their fuel tanks, while the gearbox had 8, the engine 12 and the gearbox 40. The gearbox had four forward and a backward gear, but was coupled with a reduction system which increased the total of forward gears to eight.

The FCM 12t’s suspension has often been described as a ‘Christie-type’, and shared features present in vehicles using this type of suspension. Thanks to the use of large road wheels, it could be towed without its tracks, or in emergency situations, chains could even be put up linking the drive sprockets with the front road wheels, and the vehicle could then move at moderate speeds under its own power in such a configuration.

A close-up of the suspension from the September 1948 schematics. The front sprocket was somewhat raised in comparison to the rear idler, and the puncture-proof tires of the wheels are prominent, despite the prototype seemingly not featuring them in its first configuration. Source: French military archives

The FCM 12t used four large road wheels mounted on pneumatic springs. Both the 1948 schematics and the configuration the prototype adopted in 1950 used wheels with puncture-proof pneumatic rims. However, the initial configuration of the prototype’s road wheels differ from the schematics and this later configuration. Instead, it used fully metallic wheels. Even more curiously, the front road wheel appears to have been an entirely different design from the three to its rear. The reasoning behind such a configuration is unknown, however chances are it was just due to the adequate road wheels not being ready for one reason or another. The center of each roadwheel was separated by 81.5 cm. The vehicle lacked any return rollers. It used a front sprocket and a rear idler.

83 track links per side appear to be present on the schematics. The initial tracks of the FCM 12t were 30 cm wide, but provisions were made for 35 cm wide tracks which would increase the width of the tank by 10 cm, reaching 2.5 m. The tracks featured fairly prominent guide horns.

Turrets

The FCM 12t hull was designed to interchangeably mount two different turrets.

The first was the Fives-Lilles FL 4. This was an oscillating turret, the first known French post-war development in the field. It had been designed to mount a high-velocity 75 mm anti-tank gun. On the FCM 12t, it first appeared with a ‘short gun’ that was likely the projected weapon firing at 850 m/s, but the weapon that appears to have been durably retained would instead be the “1,000 m/s” 75 mm gun, which would eventually be standardized as the 75 mm SA 50. The FL 4 oscillating turret allowed for an elevation of 13° and a depression of -6°.

This 75 mm SA 50 featured two armor-piercing shells. Both weighed 21 kg, with the projectile being 6.4 kg, and had a muzzle velocity of 1,000 m/s. The first, the POT modèle 1951/POT-51A (Perforant Ogive Traceur – ENG: Armor-Piercing Capped Tracer/ APC-T), would penetrate 110 mm at 90° and 60 mm at 30°, at a range of a kilometer. The second, PCOT modèle 1951/PCOT-51P (Perforant Coiffé Ogive Traceur – ENG: Armor-Piercing Capped Ballistic Cap Tracer / APCBC-T), would penetrate 170 mm at 90° and 40 mm at 30° at the same range of a kilometer. Lastly, a high-explosive shell existed, which had the same velocity but was slightly lighter (20.6 kg), with a projectile weight of 6.2 kg and an unknown explosive charge.

The FL 4 was a two-man turret, with the commander to the left of the gun and the gunner to the right. The reason for this reduced crew was that the turret used a bustle autoloader system, with two 6-round revolver magazines located in the rear bustle of the turret. This solution took less space than a manual loader and, as such, helped lighten the vehicle, which was necessary for the air-transportability requirement. A total of 45 75 mm rounds would be stowed within the vehicle. The turret had a coaxial MAC 31 7.5 mm machine gun, with 1,050 rounds of ammunition stored. Frontal protection for the turret would be equivalent to 40 mm, while the sides and presumably rear were 16 mm thick and the roof 10 mm.

The other turret which was to be featured in the FCM 12t was the SAMM S232 anti-aircraft turret. It was designed by the Société d’Application des Machines Motrices (ENG: Motor Machines Application Society) and was designed to be mounted on each of the three 12t light tanks projects. The first prototype was completed in May 1949.

A close-up of a SAMM S232 turret, this particular example mounted on an AMX-13 pre-production hull. Source: Les véhicules blindés Français 1944-1977

Top and side views of the interleaved road wheels version of the Batignolles-Châtillon 12t fitted with the SAMM S232 turret. Source: French military archives

Interestingly enough, the FL 4 turret appears to never actually have been mounted on the FCM 12t. The only known views of the prototype show it either without a turret, or with the S232 anti-aircraft turret, and the mobility trials were likely undertaken under these two configurations.

Artillery Version

As with the Bat-Chat and AMX, FCM designed a casemate artillery vehicle based on its 12t tank hull.

A side view of the artillery version of the FCM 12t, giving a view of the general silhouette of the vehicle, as well as the elevation and depression of the 105 mm artillery piece. Source: French military archives

This vehicle replaced the turret by a rear-mounted casemate which featured a centrally-mounted 105 mm modèle 1950 gun. The vehicle was meant for artillery use and, as such, elevation could go up to 67°, while depression went to -5°. The arc of fire was 40° forward.

A top view of the FCM 12t artillery vehicle, showing the lateral traverse of the main gun as well as the 10 rounds stowed within the rear compartment. Source: French military archives

The vehicle was to be 2.1 m high and 4.69 m long. Armor protection was of 30 mm frontally and 20 mm on the sides and roof. The weight was to be 12.5 tonnes.

The vehicle likely would have had a crew of five, as the 105 mm artillery piece on the AMX chassis eventually did, two loaders, a gunner, a commander and the driver. Ammunition stowage indicated on the schematics show 30 rounds stored towards the front of the vehicle, 15 on each side of the main fuel tank, while ten rounds were stored in the rear sides of the casemate, seven on the left and three on the right. The artillery model never reached prototype stage.

A front view of the FCM 12t artillery vehicle, showing the location of the fuel tanks and 30 frontally-stowed 105 mm rounds. Source: French military archives

Trials and Performances

The FCM 12t prototype was completed and first run by FCM in February 1949. The first preliminary trials were held in Toulon, on the Mediterranean coast, on 8th and 9th March 1949. In June 1949, a first trial concluded the vehicle provided a maximum speed of 60 km/h on-road, with a range of about 300 km. Ground pressure was of 750 g/cm² and the turning radius was of 5 meters. The tank could climb a 75% slope.

The FCM 12t in what was very likely its first configuration, with a weight taking the space of the turret, lacking pneumatic rims on its road wheels as well as having one different from the others. Source: char-français

The vehicle was transferred to the French Army’s trial center of Satory in November 1949, which led to more extensive trials being performed. On 17th November 1949, a 39 km trip was conducted between Satory and Raimbouillet to establish the performance of the vehicle. This trip began at 2:47 pm and was concluded by 5:40 pm. At 3:32 pm, after 28 km had been crossed, the vehicle stopped to assert the temperature of oil and water, which was at an adequate level. At 3:51 pm, a second stop was conducted, as a small leak of the radiator’s water tank was seen. Finally, a third stop was conducted at 4:26 pm as the water leak had, at this point, become very important.

During this trip, the FCM 12t was able to cross 1 km in 56 seconds, giving an average speed of 64 km/h. The quickest 2 km to be crossed by the vehicle were crossed in 2.15 minutes, giving an average speed of 53.5 km/h. 28 km were crossed in 45 minutes, giving an average cruise speed of 37 km/h. The vehicle was noted to be easy to pilot, with very good direction controls. The suspension was also noted to be highly satisfactory. The only real issue with the chassis were the water leaks within the radiator.

Modifications

The vehicle was handed back to FCM in early 1950 for modifications. It appears that it was at this point the vehicle received the pneumatic wheels rims and S232 anti-aircraft turret, though this cannot be certain.

French military officials observe the FCM 12t prototype, fitted with the S232 turret and four identical road wheels with pneumatics rims, during mobility trials. Source: French military archives

The vehicle was returned to the French Army for further experimentation in late 1950. However, by this point, the AMX vehicle had been picked for mass-production in December 1949. As such, while experimentation on the FCM hull continued to an extent, it was very unlikely this would result in any sort of production for the vehicle.

An accident of unknown nature interrupted the trials of the FCM 12t again in July 1951. This would practically be the end of the experimental career of the prototype. It was nonetheless restored to operational conditions by FCM and returned to the Army in 1952, but to no avail. Trials did not resume and the FCM 12t was de facto rejected. The prototype was likely scrapped in the following years, seeing as no trace of its existence appears to remain.

A side view of the FCM 12t in what was likely its final configuration. By late 1949, with the adoption of the future AMX-13, hope for the FCM vehicle to reach production was gone, but experimentation nonetheless continued in the following years. Source: Les véhicules blindés Français 1944-1977

Conclusion – One of the last FCMs

The FCM 12t was, in most regards, a decent light tank, quite comparable to its AMX or Batignolles-Châtillon competitors. While FCM only really developed the chassis, it appears to have been mostly satisfactory. Trials seem to report the vehicle provided an easy and smooth drive while the suspension was deemed very satisfactory. The only major issue with the vehicle appears to have been a leaking radiator. Nonetheless, AMX’s offering was solid as well, and would eventually be picked for mass-production, becoming what would be one of the most successful light tanks as well as French AFVs from the Cold War, the AMX-13.

For FCM, the 12t was one of the last forays into armored vehicles design, alongside a vehicle designed for the much heavier 50 tonnes tank program, the FCM 50t. The shipyard would fail to secure any orders for its first post-war designs, which was not too different from a death sentence, at least in the field of armored fighting vehicles manufacturing, seeing as the manufacturers had already been weakened by years of war. While the 12t tank program would play a major role into AMX becoming the de facto main producer of tracked armored fighting vehicles for the French Army, this was at the expense of the older FCM, of which the involvement in tank design had started all the way back in 1916 with the FCM 1A.

Side, top, front and rear views of the FCM 12t light tank

Sides, front and top views of the FCM 12t artillery vehicle

Sides, top, front and back view of the FCM 12t with the anti-aircraft turret. All illustrations created by Phanthom_25_Sniper and funded by our Patreon campaign

FCM 12t specifications (configuration with the FL 4 turret)
Dimensions (L x w x h)	6.57 x 2.40 (2.50 with wider tracks) x 2.08 m
Weight	12.5 metric tonnes
Engine	Mathis 8 G X 00
Cylinders	8 (6.560 L)
Standard rotation rate	3,000rpm
Horsepower output	210 hp
Power-to-weight ratio in hp/tonne	16.8
Gearbox	4 forward (8 with reductor) / 1 reverse
Maximum speed	64 km/h
Cruise speed	37 km/h
Fuel tanks	410 L
Range	300 km
Transmission	Front
Suspension	‘Christie-type’ with pneumatic springs
Road wheels	4
Track links	83 per side
Track width	30 cm or 35 cm depending on tracks
Crew	3 (Driver, Gunner,Commander)
Main armament	75 mm gun (future 75 mm SA 50)
Ammunition stowage	45 rounds
Elevation and depression	+13° to -6°
Loading mechanism	2x revolving automatic loading system with 6 rounds each /td>
Muzzle velocity	1,000 m/s
Maximum armor penetration at 1,000m	170 mm at 90°
Secondary armament	Coaxial 7.5 mm MAC 31 machine gun
Secondary armament	Coaxial 7.5 mm MAC 31 machine gun
7.5mm ammunition stowage	1,050 rounds
Hull armor	30 mm equivalent (front), 20 mm (sides and rear), 10 mm (floor), uncertain but likely 10 mm (roof)
Turret armor	40 mm equivalent (front), 16 mm (sides and rear), 10 mm (roof)
Number produced	1

Sources:

French military archives of Châtellerault, made available by Colasix:
Service Historique de la Défense, Châtellerault 326 3H1 27
Service Historique de la Défense, Châtellerault 326 3H1 23
Les véhicules blindés français 1945-1977, Pierre Touzin, éditions EPA, 1978
Char-français

Cold War French Prototypes Has Own Video

AMX Chasseur de char de 90 mm (1946)

Post author By Alexis Michel
Post date March 26, 2022
1 Comment on AMX Chasseur de char de 90 mm (1946)

AMX CDC. Illustrations by the Glorious Pavel Carpaticus funded by our Patreon Campaign.

France (1946)
Tank Destroyer – None Built

Introduction

Following the liberation of the country in 1944 and the recovery of factories and design bureaus previously involved in the manufacture of armored vehicles, France immediately restarted studies of modern military equipment, with the intention of catching up to the other belligerents of WW2.

The Ateliers de construction d’Issy-les-Moulineaux, or AMX, formed in 1936 after the nationalization of Renault’s facilities in the same place, were a major contributor to this initial post-war rearmament effort. Their most well-known designs of the era were the AMX M4 (the future AMX 50) medium tank and 120mm Auto-Canon (eventually known as the AMX 50 Foch) self-propelled guns.

One of the more obscure AMX projects of the period, the Chasseur de Char de 90mm or AMX CdC, recently resurfaced with its introduction in the popular video game World of Tanks.

The Chasseur de Char de 90 mm, as depicted in the plan of June 5, 1946.
Source: Mémoire des Hommes

The sole source of information regarding this tank are four plans released between January 5 and June 26, 1946, developed by Favier, an engineer at AMX. These are now stored in the archives at Chatellerault and numerized and displayed in the database Mémoire des Hommes (Men’s Memory in English) of the French Defense Ministry. The “NOM 141” mentioned on the plans, as well as the presence of components common to the AMX M4, such as the gun and powertrain, indicate that the Chasseur de Char de 90 mm was developed under the same program, but as a dedicated tank destroyer derivative.

Overall Characteristics and Layout

The CdC’s design philosophy particularly stands out compared to its medium tank and SPG brethren. While the latter two were designed for protection against the medium and heavy caliber guns of the time respectively, the CdC could only hope to withstand light autocannon and small arms fire. The layout of its powertrain and suspension was substantially altered to reduce the overall profile. This resulted in a smaller and considerably lighter vehicle.

The hull was 7.38 m long and 3.25 m wide. The height to the top of the cupola was 2.78 m, and the height to the turret roof was about 10 cm less. The CdC was relatively low compared to the Tiger II and AMX M4, both of which had a similar main armament and were about 3 m tall. The vehicle weighed 30 tonnes empty and 34 fully loaded, over 15 tonnes lighter than the AMX M4 and 120 mm SPG.

The full plan and layout of the Chasseur de Char de 90 mm of June 5, 1946.
Source: Mémoire des Hommes

The vehicle otherwise retained a mostly conventional layout. The engine, transmission, and steering elements were located at the rear of the hull. The driver sat at the front left, with an ammunition rack, machine gun magazines, and batteries to his right. His hatch was located directly in front of him, in the upper plate. The turret housed a 90 mm Schneider SA45 gun, with the gunner to its left and loader to its right. The commander sat behind the gunner and had access to a small cupola with vision slits, but no hatch. The radio was located next to the gunner and its antenna was behind the cupola. The bustle housed an additional ammunition rack, and two doors were located on either side of it at the rear to allow entry and exit out of the vehicle. This was similar to pre-war practice, with a hatch at the rear of the turret, but was rather inconvenient on the CdC, as the hatches were far behind the crew instead of being close on the roof. A travel lock for the gun was installed at the very rear of the vehicle.

The plan of June 26 showed a slightly different layout, with an automatic loading and ejection system in place of the loader. It is likely that this crew member was deleted in this configuration, but it is not confirmed.

Armament and Ammunition

The tank was built around the massive 90 mm Schneider SA45 rifled gun. This was initially designed for the ARL 44 stopgap heavy tank as a response to the German 88 mm KwK 43 L71 gun of the Tiger II, which was encountered in France in 1944. It mated a new 5.85 m long (L65) barrel to the breech of the pre-war Schneider CA Mle.39S 90 mm anti-aircraft gun. The total length with the muzzle brake and the breech was 6.530m. The barrel was monobloc and autofrettaged. The breech was of the horizontal sliding type and was semi-automatically operated, meaning that the force of the recoil would open it after the first shot. It also had a compressed air scavenging system to evacuate propellant gases.

The oscillating mass was 3,150 kg and the recoil mass was 2,200 kg. The gun used a hydropneumatic recuperator and hydraulic recoil mechanism in the ARL-44, with a relatively long maximum recoil length of 700 mm. The recoil mechanism and actual length could have been different in the AMX CdC. As mounted in the AMX CdC, the SA45 had an elevation of +20° and a depression of -10° across the 360° range of rotation of the turret, which was excellent.

This gun could shoot a 10.6 kg APCBC shell (Obus de Rupture) (Armor Piercing Capped Ballistic Capped) at 1,000 m/s (11.2 kg when using steel instead of magnesium in the ballistic cap), or a prospective 8.5 kg tungsten-cored subcaliber shell at 1,130 m/s, as well as a 11.3 kg high-explosive (HE) round at 700 m/s. Its components were capable of withstanding operating pressures of up to 300 MPa. Using the APCBC projectile, it was considered comparable to the long 88s full caliber round or the Panther’s long 75 mm APCR (Armor Piercing Composite Rigid).

The ammunition was single-piece. The cartridge was 752 mm long and its rim diameter was 144 mm. The total length was 1,126 mm for the APCBC round, and 1,161 mm for the HE. For reference, the Tiger II’s 88 mm used ammunition with cartridge dimensions of 822 and 145-146 mm respectively, and near-identical full round lengths. The weight of the AP shells was almost identical, but the 90 mm HE was nearly 2 kg heavier, possibly with a greater payload. As such, the 90 mm was almost identical to the 88 mm in performance and ergonomics without being a direct copy. However, this meant that it shared the same drawback of very long rounds that were difficult to handle in the tight confines of the crew compartment. It also meant that the tank still had to be quite big.

This gun was undoubtedly on the higher end of Western tank armament of the time, reaching greater kinetic energy with AP (Armor Piercing) rounds than the 90 mm and 20 pdr armaments of American and British medium tanks, being surpassed only by 105 and 120 mm guns at the time being tested on the T29 and T34 heavy tanks and the French 120 mm gun then proposed for the self-propelled gun derivative of the AMX M4. However, the AMX M4 medium tank carried the same 90 mm piece, so firepower was not the outstanding feature of the tank destroyer.

The SA45 suffered heavily from the poor state of the early post-war French industry, with many defects encountered during production and testing of the ARL-44. The mechanical properties (rupture and elastic limits, elongation) of the barrel were also relatively poor compared to later production guns, such as the 75 mm SA50, limiting tube life relative to the operating pressure, and thus, the overall longevity of this armament. Its old technology led to excessive weight by post-war standards. By the early 1950s, even more powerful guns, such as the 100 mm SA47 and a 120 mm gun, superseded it in the AMX 50 program. Had the AMX CdC survived until this period, it would likely have evolved to carry either of these two weapons.

Layout of the fighting compartment in the manually-loaded configuration.
Source: Mémoire des Hommes

The CdC had a rather unique ready rack layout, even in its manually-loaded configuration. Thirty-six rounds were stored below the turret ring, facing nearly upside down in a crown or carousel covered by a metal sheet. The crown could rotate independently of the turret to present a new round to the loader, who had a small door next to him. This layout greatly simplified his job, as he only had one specific place to access the ready rack, and it freed space in the crew compartment. The metal cover for the rack may have also increased the survivability of the crew somewhat in case of ammunition detonation, but this would have depended on whether its thickness could stop fragments or not. Conversely, it may actually have been intended to provide additional protection for the ammunition in case of penetration by low-energy fragments and small-caliber ammunition.

Layout of the turret and ammunition crown controls as of January 9th, 1946.
Source: Mémoire des Hommes

Fifty-four additional rounds were available, 24 in the bustle, and 30 in the front hull, at the right. It is unclear exactly how that latter rack could be accessed from the inside, so it may have been purely intended to replenish the bustle rack from the outside, while the easily-accessible bustle ammunition was used to replenish the carousel. The presence of an unprotected bustle rack alongside a covered carousel is quite surprising from a survivability standpoint. Compared to Cold War vehicles, 90 rounds of ammunition was excellent for the caliber, but more or less in line with the Tiger II and the AMX M4. If one also considers the bustle rack as ready ammunition, then the CdC carried a whopping 60 ready rounds, nearly as many as Western Cold War tanks with 90 or 105 mm guns (or the Chieftain) carried in total.

The secondary armament consisted of one 7.5 mm MAC 31 Reibel magazine-fed machine gun mounted to the left of the driver and operated by him (but seemingly fixed) and the same machine gun mounted coaxially to the gun. Twelve drum magazines were installed to the right of the driver for his machine gun, and 6 on the turret roof inside the turret for the coaxial machine gun. Assuming the magazines carried 150 rounds each, as usual, this would be 2,700 bullets in total.

Automatic Ejection and Loading Device

Layout of the proposed autoloader and ejection system in the turret.
Source: Mémoire des Hommes

Automatic loading and ejection of spent cases were also contemplated. This made a lot of sense considering the difficulty of manually handling the very long 90 mm rounds. In this configuration, the carousel held 35 rounds instead of 36. The autoloading and ejection mechanisms were very complex but relied on springs and compressed air/water pistons for operation.

The loading process can be separated into 3 phases. The gunner would use his command stick (which also acted as a firing trigger) to select either an AP or HE round (respectively marked as “R” for Rupture or “E” for Explosif). The clamps retaining the round would open, while the clamps of the autoloading mechanism would grapple the round and rotate it. At this point, the round would be parallel to the gun and offset to the left of it. The mechanism would then rotate around the forward axis to place the ammunition in the gun breech’s axis (2nd phase). In the last phase, the round would be automatically rammed inside the breech.

Plan of the components and layout of the autoloading mechanism.
Source: Mémoire des Hommes

After firing, the empty case would be received by the ejection mechanism. The mechanism could hold 2 cases, one waiting, and one in the process of being ejected. The empty case would have been ejected out of an obturator at the base of the turret rear. The ejection also triggered the evacuation of gases outside of the crew compartment. The entire mechanism itself worked for any position of the turret and gun.

Plan of the ejection mechanism.
Source: Mémoire des Hommes

Protection and Survivability

With the exception of the cast gun shield, the vehicle used only welded steel plates. The front plates and gun shield were both 30 mm thick and well-sloped, while the other surfaces were all (except for possibly the floor) 20 mm thick and nearly vertical or horizontal. All-round protection would thus be expected against small arms and shell fragments only, although a level of resistance against US and Soviet armor-piercing 12.7 mm bullets was possible. The front might have been able to handle 14.5 mm bullets and 20 mm AP rounds, especially the area behind the gun shield, due to the locally spaced configuration of the armor and the extreme slope of the gun shield itself.

Although the turret ring sat above the hull roof, the turret was shaped specifically to hide it, limiting the likelihood of bullets and fragments jamming it to some degree.

An automatic fire extinguisher was located to the left of the crew compartment, behind the driver. Overall, the CdC followed a very similar philosophy to the American M18 Hellcat and the British Avenger of WW2, both being lightly armored but highly mobile turreted tank destroyers.

Powertrain

Following WW2, France was stuck with no indigenous solution for a high-power engine. Fortunately, the French managed to get their hands on Maybach factories, engines, and blueprints in their occupation zone in Germany. German components were extensively used and studied in early post-war powertrains.

In the case of the CdC 90, as well as other members of the AMX M4 family, the Lorraine 40t and the Somua SM, the choice fell on the Maybach HL 295 fuel-injected gasoline engine and the synchromesh AK 5-250 5-speed gearbox, a derivative of the AK 7-200 used in the Panther. This engine was developed by the Maybach design team in Vernon and was supposed to be built by the Maybach factory at Friedrichshafen, with Renault being considered as the most suitable option for French production.

The HL 295 was a water-cooled, fuel-injected gasoline V12. It was essentially a higher displacement version of the HL 234 (fuel injected, reinforced HL 230), going from 23 L to 29.5 L. Plans indicate that 27.5 L was initially considered. The HL 295 was 1,392 mm long, 1,060 mm wide, and 1,200 mm tall. In comparison, the 230 was slightly smaller, being 1,310 mm long, 951 mm wide, and 1,185 mm high. The French appreciated the compact nature of the Maybach engine, in particular its short length, which would minimize engine compartment size and weight.

This increased displacement was sought both as a way to ensure it would reach the desired performance, and to increase its future potential. The French initially thought that it could reach up to 1,200 CV (Metric horsepower or 0.986 hp), but it became clear by 1950 or so that 1,000 CV at 2,800 rpm was the most they could hope for. This is in line with fuel-injected engines of similar displacement, like the American AVSI-1790-8.

In practice, various reliability issues meant that the HL 295 was usually operated at 850 CV at 2,600 rpm. Maximum torque of 2,403 Nm was obtained at 960 CV at 2,800 rpm in one test, and usually varied between 2,354 and 2,550 Nm over the operating range of the engine. Fuel consumption varied between 230 and 250 g/CV.h.

Characteristics of the third prototype of the HL 295, as installed later on the SOMUA SM.
Source: SHD Châtellerault AA 503 1H1 27

At 34 tonnes and 1,200 hp, the CdC 90 would have had a whopping 35.3 hp/t power-to-weight ratio, far beyond even the requirements of the FINABEL 3A5 (or Europanzer) program of 1957. Even with the more conservative value of 850 hp, the CdC would have kept 25 hp/t, well in excess of most tanks of the period.

The transmission was located at the very rear of the vehicle under two large ventilation fans. In front of it was the engine. This installation occupied half of the length of the hull. Interestingly enough, this layout was low enough to allow full gun depression to the rear. However, it seemingly contributed to an increase in hull length, as the contemporary AMX M4 was nearly 50 cm shorter, with the fans on either side of the engine.

Engine compartment of the Chasseur de Char de 90 mm.
Source: Mémoire des Hommes

Suspension

The suspension was probably the most peculiar aspect of the Chasseur de Chars. The spring element chosen was the torsion bar, which was nearly the norm by this point. However, unlike contemporary French, US, and Soviet vehicles, these were mounted internally along the hull sides, going towards the front at an angle (parallel to the front-rear axis of the vehicle). The closest equivalent in a production vehicle would be the Christie-type suspension with coil springs also being mounted along the sides at an angle, although torsion bars would likely have more desirable properties. Why AMX went for such a radical design on this specific vehicle, when the M4 and 120 mm SPGs used regular transversely-mounted torsion bars, is unclear. A possible explanation is that the engineers wanted to reduce the height of the vehicle and could afford to sacrifice some of the width, which would make sense for a tank destroyer.

Outside of the sprocket and tensioning wheel, there were five double road wheels per side, each spaced 1.04 m apart. These were extremely large, with a diameter of 1 m. In this regard, they remained somewhat similar to the large wheels used on German and French interleaved suspensions. There were also three 300 mm diameter return rollers per side.

This suspension offered an impressive range of travel for the road wheels: 200 mm bump and 160 mm rebound, for a total vertical travel range of 360 mm, well above that of contemporary vehicles, limited to around 250 mm or less. Only British Cruisers or the Panther could match or exceed this level of performance. Overall, this suspension would have offered excellent mobility.

Layout of the suspension. The mounting points for the torsion bars can be seen on the right.
Source: Mémoire des Hommes

Mobility

Two 550 L and two 300 L fuel tanks were located in the engine compartment, providing an impressive 1,700 L capacity. Post-war gasoline-powered French vehicles typically carried a much greater fuel capacity than their Western counterparts to ensure an adequate (300 km) range. The CdC is referred to as having a 6-hour autonomy without refueling. Assuming that this was with a 300 km range, it would require a maximum speed of at least 50 km/h. However, if French requirements involved some off-road driving or an actual range greater than 300 km, it would be absolutely possible to go beyond this limit and towards 60 km/h or more.

In any case, the suspension and powertrain easily allowed such high speeds. Indeed, the CdC might actually have been able to achieve more than 80 km/h on roads, like the American M18 Hellcat.

Going by the ground contact length of 416 cm per track and 40 cm track width, the total ground contact area would be 16 640*2=33 280 cm². For a combat weight of 34,000 kg, this gave a ground pressure of 1.02 kg/cm² or a bit over 14.2 psi. Ground clearance was 400 mm, roughly standard for the time. The CdC’s relatively narrow tracks resulted in a somewhat high ground pressure for the period. Indeed, the ground pressure of a Comet Mk I Cruiser Tank was 13.85 psi. The Sherman with the HVSS suspension, with a more favorable ratio of track width to vehicle weight, had a ground pressure of 11 psi. This limitation was probably inevitable considering the choices with the layout of the suspension, the width taken by the carousel, and transport requirements.

Conclusion

The French showed relatively little interest in tank destroyers during the interwar period, restricting themselves to concepts of anti-tank guns slapped to existing hulls or powerful and heavily armored vehicles dedicated to the protection of intervals between fortifications.

The defeat at the hand of German tank formations in 1940 and the generally intense use of armor during WW2, led post-war France to make a considerable effort in the design of dedicated anti-tank vehicles, be they HEAT (High Explosive Anti-Tank) slingers such as the ELCs, or ATGM carriers or AT gun carriers such as the S35 and R35 hulls with 17 pounders. The AMX CdC, however, used the most original design philosophy out of all these concepts: a turreted vehicle with a gun shooting kinetic energy projectiles with similar power to the medium tank, with an emphasis on high mobility, lower weight, and smaller size.

Unlike other members of the AMX M4/50 family, which even participated in the Bastille Day parades, the CdC never spawned any prototype. The closest thing to a spiritual successor would be the Lorraine 40t, also lighter than the medium tanks, thinly armored, and equipped with a normal (by French standards) gun with an autoloader. At present, it is unknown when and why the AMX Chasseur de Char de 90 mm project was terminated.

AMX CDC. Illustrations by the Glorious Pavel Carpaticus funded by our Patreon Campaign.

AMX Chasseur de Char de 90 mm specifications
Dimensions (L x w x h)	9.23 (gun locked for travel)-7.38 (hull) x 3.25 x 2.78 m (top of cupola)
Weight	30 t empty, 34 t fully loaded
Crew	4 (Driver, Gunner, Loader, Commander) 3 (Driver, Gunner, Commander) with autoloader
Propulsion	2.5 litre 6-cyl Daimler petrol, 55 hp (41 kW), 18.3 hp/ton
Number of gearbox speeds	5
Engine	Maybach HL 295 water-cooled V12, 1,200 hp expected
Fuel capacity	1700 L
Suspension	Longitudinal torsion bars
Ground clearance	400 mm
Top Speed	Unspecified, beyond 50 km/h
Autonomy	6 h of travel
Armament	Schneider 90 mm SA45 rifled gun (90 rounds) 2 x MAC 31 7.5mm machine guns (1 coaxial, 1 hull, 2,700 rounds)
Armor	Welded and cast steel, 30 to 20 mm

Sources

Mémoire des Hommes (AMX CDC)
Mémoire des Hommes (90mm rounds)
Armement de gros calibre, Tauzin & Marest, 2008 (90mm SA45 data)
Les Archives de Châtellerault, Colasix (HL 295 data)
Panzerworld (88 rounds)

Cold War French Prototypes Has Own Video Modern French Prototypes

Wieczorek Engin blindé de combat (EBC) and Engin blindé de combat lourds (EBCL)

Post author By Andrew Hills
Post date September 15, 2021
4 Comments on Wieczorek Engin blindé de combat (EBC) and Engin blindé de combat lourds (EBCL)

France (1986-2000)
Main Battle Tank – None Built

Patents, the government license issued to an inventor or company to commercially protect or exploit an innovation or design, are wide ranging and can be as small as a new way of doing something up to a total rethink of how an existing thing might work. Julien Wieczorek, a Polish national living in France, falls into this latter category. Between 1986 and 2000, he submitted a set of design patents for a completely new tank. That is, a tank not just new in design, but new in philosophy as well. Wieczorek’s designs are from a skilled engineer looking at some of the fundamental problems associated with tank design and finding a way to work around them to produce a new bigger, and better tank. A tank with formidable armament, impenetrable armor, and a level of mobility to surpass any contemporary vehicle in NATO or beyond. His designs were not built but they not only provide an insight into some alternative solutions to the technical limits of current tanks, but perhaps also more widely into the design of modern tanks at the turn of the Cold War, where massed tank combat became less and less likely. At a time when nations were reducing tank numbers or seeking lighter and more ‘flexible’ vehicles, Wieczorek doubled down with a design nearly twice the weight and larger than any other – a true super tank for the 21st century.

The Man

Julien Wieczorek left a long catalog of engineering and design work in the patent office, yet is somewhat hard to trace from just those records. What can be discerned from them, however, is that Wieczorek was a Polish citizen who was living in France. His address, provided in British and American patent applications, showed him living in an apartment complex in Les Fougeres A2-36, Avon, which is southeast of Paris.

Wieczorek was clearly a professional engineer rather than the amateur armchair type of inventor. This is evidenced by the fact that he had taken part in one of the submission ideas for the road/rail link between the United Kingdom and France which became the Channel Tunnel. His idea was for a large suspension bridge and barrage-type crossing rather than a tunnel.

Over the years, Wieczorek had turned his mind to all sorts of large civil engineering projects, from commercial ship construction and a modular passenger aircraft (1969), a method of moving a large iron furnace by sea (1970), bringing water to the desert (1974 and 1984), and even plans for a new European capital between Berlin and the Polish border (1999).

On the military side of things, Wieczorek was no less inventive, with ideas for multiple drone fighters controlled from a single aircraft (1977), a huge flying boat which could launch and land fighters as a flying aircraft carrier (1977), a means of creating an artificial island as a military air base (1987), and a dual body helicopter with intersecting blades (1989-1990). Of particular note, however, are three designs from him relating to armored vehicles.

Twin-rotor dual-body helicopter designs, 1990. Source: French Patent FR2659934

The first was filed in October 1986, titled ‘Independent armoured modules for the driver, observer, and gunner for an automatic-loading armoured fighting vehicle’. The patent was granted in April 1988 as French Patent 260509. The second of these was filed as ‘Additional armour units with rocket-launching systems for an armoured fighting vehicle with automatic loading’ in March 1987. The application was granted in September 1988 as French Patent FR2613061. The third design was filed in August 1996 titled ‘Method for constructing, repair, maintenance and transport of heavy armoured fighting vehicles consisting of several modules’. This filing was also approved and a patent was granted in March 2000 as French Patent FR2782789 and European Patent EPO982560. There is significant overlap between all of the ideas in those patents as the idea has evolved in this time.

Spanning a period of not only nearly 14 years but also straddling the collapse of the Soviet Union and the new political situation in the world as a result, the designs are still complementary to each other, with a lot of similarities. As such, looking at these designs together provides a view of the thinking of Wieczorek and ideas which he wanted to build into a new generation of heavy main battle – one which was not only capable of dominating the late Cold War battlefield, but also the new post-Soviet world.

Birth of the EBC 1986

The first two designs are deliberately linked by Wieczorek in his applications, with FR2613061 (March 1987) directly referencing the slightly earlier application which was granted as FR2605095 (October 1986). The vehicle in FR2613061 was, for 1987, certainly ahead of its time in several areas, not least of which was an overall shape of a slab-sided tank which stands apart from its cast steel and rounded predecessors from the 1970’s or before, whether it was the British Chieftain, French AMX-30, or German Leopard 1. In fact, Wieczorek alludes to the inspiration for this new shape as coming from the public unveiling of the new French tank, the replacement for the AMX-30 known as the ‘Leclerc’ at Satory, France in 1987.

This new vehicle was what Wieczorek called an “Engin Blindé de Combat” (English: an armored combat vehicle). Wieczorek has preceded this unveiling with his own submission in October 1986, which was eventually issued as French Patent FR2605095, which was notionally about the separation and individual protection of crew positions within a new autoloaded main battle tank.

Design of the 1986 Patent

Dimensions

The 1986 vehicle is only mentioned as being of a similar size to modern Main Battle Tanks such as the M1 Abrams and Leopard 2. This probably means a length (without gun) of about 10 m, a width of 3.5 m and a height of about 2.5 m.

Crew

In the French patent from 1986, Wieczorek is clear that his goal was the creation of a modern tank that used an autoloading system to reduce the crew from 4 men to just 3, as it would no longer require a human loader.

The three crew members would sit in separate armored pods placed in the turret and the hull. The driver would stay in the hull in the 1986 patent, whilst the gunner and commander would stay in the turret in their pods. It is made clear, however, that, although the vehicle is shown with the driver in the front and engine in the back, it was also possible to put the engine and transmission in the front in a manner akin to the Israeli Merkava.

Wieczorek also avoided the common design choice of moving all the crew members into the hull for extra protection, preferring to maintain the observation advantage given by an elevated position. The tank commander would be located on the right, whilst the gunner would be on the left in the turret.

Despite being separated by their individual armored pods and being physically apart within the vehicle, the 1986 patent makes it clear that they would be in communication with each other continuously using both video and the internal radio communications.

The driver seems to have had access to three vision ports mounted on a rounded hatch. It is unclear how this hatch opened and if it would have interfered with the gun or turret. The commander had access to eight vision ports on his cupola, while the gunner on the left had access to four vision ports and a telescopic sight. Of course, these were just tentative placements, as the patent did not concern itself much with such details.

The great advantage of pods, except for the obvious addition of protection, was the supplementary protection of the crew from internal fires, explosions, fire extinguisher gases and NBC threats. It was far easier to insulate just the small pods than the entirety of a fighting compartment.

What Wieczorek seems to pay no mind to is the psychological comfort of the crew. While being in the small confines of a tank with other men in combat is certainly not a calming situation, finding yourself alone closed off in an even smaller space is possibly even less so.

The three compartments for the crew are clear in this top-down view from French Patent FR2605095 of October 1986. This idea remained through to the March 1987 patent, albeit with the driver’s modules moved to the rear. Source French Patent FR2605095

Protection

Like other heavy tanks, Wieczorek’s design was planned to be well protected by means of a modern multi-layered arrangement, presumably composite armor. The sides of the vehicle would be covered by very thick side skirts that were connected to the hull over the tracks and to the extended magazine in between the tracks.

Wieczorek also mentions that, should a front-engine arrangement be chosen, the engine itself can help protect from a part of the shrapnel.

To protect against fire, including from fuel, ammunition, or hydraulic fluid, Wieczorek proposed an automatic fire fighting system based on releasing a gas concentration of 5% Freon 1301 (Bromotriflouromethane – CBrF3). This, he postulated was preferable to alternative systems like Halon as it was roughly as toxic as Carbon Dioxide and could only be tolerated by the crew for up to 5 minutes.

Should anything manage to penetrate the outer armor of the tank, or should a fire ensue inside, the crew were protected by their individual pods. Those ‘pods’ were to be made from a composite material involving steel or some other and lighter alloy and Kevlar. This provided protection from shrapnel and fire alike.

Automotive

Very little is mentioned in the 1986 patent about the automotive components of the engine. The engine and the transmission are at the rear of the vehicle, under a raised engine deck cupola with two large fans for cooling. The air intakes are on the side of the vehicle. It should be noted that the space allocated for the engine and transmission is very small.

However, Wieczorek mentions not only that these components can be moved to the front, but also that it should be possible to mount two engines and two transmissions, one at the front and one at the rear. How wise such a solution is mechanically and space-wise is not discussed by the inventor.

It is not exactly clear where the fuel tanks are supposed to be, although it is possible they were meant to be placed in the floor of the hull.

Suspension and Track

The tank was to be supported on 7 sets of double road wheels on each side. Each pair of wheels was fixed on a common trailing arm. Unusually too for the design, was that the roadwheel pairs were not all the same size. The leading two and rearmost two pairs of wheels were of a larger diameter (750 mm) than the 3 central pairs (600 mm), as this decrease in height allowed for the hull width extensions inside the track run. Making them slightly smaller allowed them to still deflect upwards by up to 200 mm without striking the hull side extensions.

The drive sprocket was to be at the rear, the idler at the front and just two return rollers were used, one on each side of the bulging ammunition compartment.

Side and top-down views from French Patent FR2605095 showing the unusual arrangement of the 7 road wheel pairs to allow for the hull side extension needed for the autoloader carousel. Note the track return rollers either side of the hull side extension. Source: French Patent FR2605095

Although the drawings appear to show torsion bars across the width of the bottom of the hull, this is misleading. Wieczorek determined that torsion bars would not provide suitable suspension across the potential temperature ranges in which the tank was potentially going to operate at, namely -55 C to +60 C, and, therefore, the design would use hydro-pneumatic suspension instead. This system would allow for both manual and automatic adjustment of height, meaning Wieczorek’s design would be able to keep good ground clearance for off-road running and then lower itself in a fighting location to the extent of the hull floor being in contact with the ground. This allowed the vehicle to make itself a smaller target as well as harder to see.

Armament

The tank would engage an enemy with its primary armament – an autoloaded 120 mm gun. Ammunition for the main gun was to be either Kinetic Energy (KE) i.e. Armor-Piercing Fin Stabilised Discarding Sabot (APFSDS) or High Explosive Anti-Tank (HEAT), which Wieczorek called a ‘multi-purpose round’. With an assumed overall weight of 55 tonnes, 40 rounds of these shells at 20 kg each would be just 800 kg, or 1.45 % of the overall mass of the tank. As such, Wieczorek saw that as long as they could be made to fit in the space of a tank, then increasing ammunition storage could increase the firepower of the tank without much of an increase in mass. The plan therefore, was to adopt an 80-round loadout for a total of just 1.6 tonnes / 2.9% of the total mass.

The autoloader speed was estimated to be able to provide 10 to 12 rounds per minute, but far more unusual than the prospective high rate of fire was the layout of the loading system and how Wieczorek amended the hull shape to accommodate it. The problem was going to be where the autoloader would go. If he could make it fit and potentially cram in 80 or more rounds then this tank would be carrying twice or more than its equivalent Western MBTs. His solution was to place the ammunition in the bottom of the hull, in two large circular carousels.

No secondary armament is mentioned in the patent.

Ammunition Resupply

As previously mentioned, one of the advantages of carrying more ammunition was less frequent reloading and less exposure outside of the tank by the crew. Wieczorek proposed the use of a semi-trailer to be towed by the EBC and then used to reload the two magazines. The two magazines would be reloaded through the belly of the tank through two intermediary magazines.

Autoloader

Wieczorek was clear even in the first filing in October 1986 that the goal was an autoloaded tank to both increase firepower and also to reduce the number of crew from four to three. In his journey to deciding on an autoloader, he considered the alternative MBT autoloading projects of the time. The Soviets had their own 125 mm autoloader on the T-72 MBT and clearly, in some quarters, it was felt that this gave a firepower edge over Western vehicles. From the USA, Wieczorek looked at the Tank Automotive Command (TACOM) projects to replace the M1, known as the SRV and TTB, both of which used a drum under the turret storing 40 rounds with a rate of fire of 8 rounds per minute. The Leopard 2 120 mm smoothbore autoloader project from the firm Rheinmetall in the Federal Republic of Germany (West Germany) could hold just half of that number of shells, just 20, and these were held in the back of the turret. The British had their own projects with several ideas considered by the Royal Armament Research and Development Establishment (R.A.R.D.E.) and one from Alvis which loaded an externally mounted gun from an ammunition supply on the back of the tank.

The French too were in the process of finding a replacement for the elderly AMX-30 in the form of the new ‘Leclerc’ MBT and a variety of ideas for what that vehicle would eventually look like had been proposed. Ammunition storage for an autoloader had featured within that work too and had, at one point, even included the same kind of idea as considered by Alvis, with ammunition at the back in a pod for restocking the autoloader.

Mock-up model of the Leclerc with the rear-mounted external ammunition resupply pod concept. pholdeer.com

Storing additional rounds in pods on the back was not going to be a viable solution and was just one of several ideas floated around to bolster the available stock of ammunition. If the ammunition stowage for the autoloader was going to be in the back of the turret, then it was going to be limited by the volume available, although it had the advantage of accommodating the length of a unitary shell well. Nonetheless, not more than 20 or 30 rounds could be carried effectively in this manner and, if there was a move to an even larger calibre gun of say 140 mm, then even fewer could be carried due the width of the shells and the dimensions of the bustle rack. The solution to this was to put the rounds in the hull and this is exactly what the Soviets had done with the carousel-type loader on the T-72. However, herein lies an additional problem – hull width. Unitary 120 mm caliber shells would not be able to fit in a normal type of hull with a carousel autoloader, so even considering 140 mm rounds in such a way was completely out of the question.

The greatest single limiting factor in tank design is not weight, nor speed, or even cost – but width. Width, because most long tank movements are by rail and this means the railguage limits how wide of a load can be transported without fouling on a neighboring track, platforms, or bridges. This is generally around 3 to 3.5 meters in real terms for maximum width and excluding any side armor modules added later. This has been the fundamental maximum width, give or take, since the very first tanks in WW1. When Wieczorek was considering his carousel-type loading system with shells arranged in a circle and pointing inwards, this width restriction was the source of serious problems.

The length of a tank shell, such as a 120 mm NATO APFSDS, is 1 meter. Arranging such full-size shells on a carousel would mean placing them facing each other, doubling that in terms of required width. Even before considering the mechanism of the carousel to rotate it or move the shells to deliver them to the gun, a full 2 meters of the internal width of the tank is taken up. Allowing just 10 cm all around the outside of the carousel (total diameter 2.1 m) for clearance, problems can be plotted out as per Table 1 using a simple theoretical limit of 3 m of width to illustrate the problem.

On a conventional hull, where the sides of the hull do not project through or over the tracks (Table 1 Row a) and where the overall width is 3 m, it has to be factored in that the tracks on each side deduct from this maximum width. A track of even 60 cm width on each side, a little clearance between the hull side (~5 cm) and the track, and then the thickness of the hull sides (~4 cm) means a central internal space of just 162 cm – well short of being able to make a carousel autoloader using unitary shells.

This is one of the reasons why Soviet tanks using a carousel type loader tend to split the shell up into two parts (propellant and shell) and automatically load both parts to form a single shell. That ingenious solution is certainly very clever, but when it comes to an APFSDS round, one of the factors affecting anti-armor performance is the length of the APFSDS rod itself. Generally speaking, longer rods are preferable to shorter ones so, if your shell is split in two pieces, it is inherently harder to get a longer APFSDS rod. The goal, therefore, is to have a unitary shell to keep the APFSDS rod as long as possible. Assuming this was done with a conventionally laid out tank where the tracks and suspension project from the sides of the hull (Table 1 Row b), then the only possible solution is to have very narrow tracks. This is even more acute, as even larger calibre guns with longer unitary shells are considered and clearly, the central width could be made larger, the tracks get substantially narrower, which is limiting on the performance.

Wieczorek’s solution (Table 1 Row c) skipped deftly around this problem. As can be seen from the table, it can retain a track of the same width as the conventional or normally laid out tank and still provide substantial internal width without exceeding the maximum 3 m overall tank width limit. The dimensions for Wieczorkes tank were actually a maximum hull width of 3.42 m and, with the side skirts on, a total width of 4.3 m.

The way this was done was simply to revert to using sponsons – projections from the side of the tank. These projections did not go over the track but actually projected within it, so that the track ran both below and above the projection. In doing so, the tank could increase the maximum available width for a carousel autoloader and fit those unitary rounds. This available width was increased even more by angling the rounds so that they pointed down and thus decreased the effective width taken up. It also meant one more thing for Wieczorek’s design – the ability to create a double stack of such shells and increase the ammunition capacity of the tank.

Wieczorek decided to place the APFSDS and HEAT shells on separate stacks, with the APFSDS in the top one in his drawings. This would then allow for very simple choosing of the next shell to be loaded, making it very easy to keep track of which shell is which. Both the gunner and the commander could select what type of round would be loaded next. These would be loaded into the gun by two ‘robotic’ mechanisms.

The spacious turret is largely occupied by two things – the individual protective cabins for the crew and the breech of the main gun. The ingenious double-stacked carousel autoloader fits neatly within the hull, where it is well protected. Source French Patent FR2605095

1987 – Rocket Armor!

While the 1986 patent set the general tone for Wieczorek’s view of how a modern MBT should look, the 1987 patent came in and added rocket launchers to the vehicle. The grand idea of Wieczorek’s new patent was that his EBC could use the rockets carried inside the sides of the turret and hull to bombard enemy positions before being attacked by massed enemy tanks. The launchers would then remain to act as armor for the tank.

Design of the 1987 Patent

Crew

The 1987 patent followed up from the 1986 one, keeping the idea of crew pods for the men in the tank. However, citing critical voices within the army about the reduction of the tank’s crew to 3 men, Wieczorek added another crew member and reshuffled all of their positions.

The only crew member to retain his position was the gunner, remaining on the left side of the turret. He was accompanied by the new crew member, probably placed on the right side of the turret, the observer. What this man’s actual duties within the operation of the tank were supposed to be is not specified. They would be further protected by individual armored pods, creating in effect a semi-turret position for both of them, where most of their bodies would actually be below the turret ring.

The most drastic changes, however, were the placements of the driver and commander. They were moved from their initial positions into the middle of the tank, sandwiched between the turret and engine, in their own protected capsule. While this would arguably have been the safest place in the tank, it would also have provided significant problems with access and, most importantly, emergency exits. They would have to use cameras and displays to see their surroundings, drive and control the tank. It is worth noting that, in several countries, this would also mean his tank would not be legal to use on the road in some countries as the driver would have no ‘eyeball’ view of the road ahead of the vehicle.

Protection

This move of the driver into the rear of the tank divided the vehicle into a front unoccupied compartment, a sealed-off armored turret compartment, including the space under the turret (which was used for the loading system), and the two spaces at the rear for the crew compartment and engine/transmission, respectively.

Cross-section side view of the tank showing the location of the driver safely ensconced in the rear sandwiched between the turret ring and engine. The front space, formerly occupied by a driver, has become a heavily armored and moveable rocket launching pod isolated from the rest of the tank. Source: French Patent FR2613061

It is said that the best defense is attack and Wieczorek took this to heart with perhaps the least well-considered part of his idea – fitting bombardment rockets to the sides of the turret, the sides of the hull and the hull front. The rocket pod in the front of the hull, whether full or empty, also created a large distance from the outer armor to the crew space, forming a heavily protected frontal aspect made from composite armor with a line of sight thickness of 2 to 3 metres in places. However, this also meant that a large weight would be added to the design and a lot of mostly useless space would be present, space that could far better be used for something else (or removed altogether).

This, Wieczorek felt, would provide protection against the current Soviet 125 mm caliber tank guns and also guns up to 140 mm caliber, which were being hypothesized as potential future tank guns.

Seen in cross-section, the heavy side armor on the turret and spaced armor over the side hull extensions is clear. Also note the rocket launchers on the sides of the turret and hull French Patent FR2613061.

Just as the rocket pod in the front added a substantial level of protection, Wieczorek provided for the rest of the tank to be well protected too. The cross-section of the tank from French patent FR2613061 shows not only a heavily reinforced floor to protect from mines, but also a heavily protected turret both on the sides and roof. Not only are the sides of the turret thick, allowing for an arrangement of armor that can make good use of that space, like a spaced or composite array, but the bottom sides of the turret extend out forming a shelf on each side. Onto this shelf was an angled and armored compartment containing the rockets. Regardless of whether the rockets were a good idea or not, the pocketting of this area meant a well-shaped and angled spaced armor layer with a good distance from the sides of the equally well-angled turret sides.

Assuming the rockets were dropped as a poor idea, the basic turret shape, as outlined with these pockets, would allow for space on the sides ideal for stowage of maintenance or crew equipment whilst keeping the outside of the tank clean and uncluttered – something important to provide the vehicle with a small radar signature to help keep it hidden. A similar concept was indeed adopted on the Leclerc, with stowage modules on the turret sides.

French Leclerc MBT showing the turret boxes open and used for stowage. Closing the boxes keeps the exterior clear of clutter as well as allowing for extensive stowage for all of the kit used by the crew for themselves and to maintain the tank. Source: Pinterest

Moving vertically downwards from the shelf of the turret side was a trackguard to keep mud from being thrown up onto the deck of the hull. The top run of the track then ran in the gap below this mudguard and the top of the hull side extension. The extension itself was the same width as the outer edge of the turret shelf and is clearly drawn with a double thickness of armor over the projection, providing for additional security of the ammunition which lay directly behind. Moving down the hull side, below the extension, the hull then cut away sharply at an angle down to the belly plate, with the suspension units attached to this inwards angled lower hull side. Not only would angling this lower side add an increased level of protection to direct fire with a sloping surface and increased line of sight thickness, but it also improved the lower hull shape of the tank to provide increased protection from explosions underneath, such as landmines.

Cross-section side view of the tank showing the very heavy protection at the front both on the hull and turret and the unusual double stacked and angled carousel autoloader. Source: French Patent FR2613061

On the outside of the hull were the other rocket pods. Formed into long side skirts full of rockets, it actually created a double-thickness side skirt for the tank along its length. It particularly added value to the tank in providing additional coverage over the side extensions with the ammunition in them. However, Wieczorek makes it clear that these pods were optional and would only be fitted to the tank when required to fight from a defensive position. They would have made the tank too wide to be transportable.

Just like the turret sides, if the rockets were dropped, the extensions could be repurposed as large open boxes for stowage or an additional form of armor array. Just as with the turret side rocket pods being hollow boxes on the real Leclerc, here the hollow side skirts could be interpreted as being along the lines of the box-like extensions which ended up on the front of the Leclerc.

Cleaned cross-section of the March 1987 vehicle showing key elements of the protection including tack (blue), permanent hull armor (red), moveable hull armor (green), permanent turret armor (orange), moveable turret armor (yellow). The rocket modules are shown without rockets to show the extent of armor modules which might be fitted (pink). French Patent FR2613061 amended by Author

Mobility

In terms of power for this 55 tonne main battle tank, Wieczorek wanted something better than either the Ka-500 series 12 cylinder MTU diesel, as used on the Leopard, or the engine on the Leclerc, which he called the “Suralmo Hyperbar” – a high-pressure gas turbine. Instead, he preferred the idea of a pair of MTU-880 V8 diesel engines combined with an automatic gearbox. Each engine was capable of delivering 1,000 hp and the pair together a total of 2,000 hp. At 55 tonnes this would have meant an incredible 36.4 hp/tonne. Without all of the rockets of dubious practical value, possibly saving another 5 tonnes, it is reasonable to estimate he could have been looking more towards 40 hp/tonne assuming all of the other elements remained viable.

The track itself was made from steel, light metal, or composite materials, such as polyester reinforced with kevlar or glass fiber. It would be fitted with three rubber pads on the outside across the width, with the center pad of those three slightly thicker than the ones on either side. On the inner face of the track, the links were cushioned with kevlar pads. Across the top of the track run, the track would slide along the top of the hull side extensions but was supported at each end by a single return roller. The suspension type was retained though to the 1996 patent application.

View of the composite track links with the 3 pads shows the larger centre pad to be offset to the smaller ones on each side. Source: European Patent EP0982560.

Rockets

Wieczorek planned to use technology to disrupt an attacking enemy tank force starting at ranges beyond those for direct tank fire. This was to be fulfilled by using supplementary rockets. These were not to be just any old rockets either, but were to be a version of the Multi-Launch Rocket System (MLRS) which was at the time in service with the United States, France, the United Kingdom, the Federal Republic of Germany (West Germany), and Italy when the need was for long-range enemy suppression. Able to inflict damage well beyond tank-gun range, the MLRS rocket modules on the turret sides could deliver high explosive or presumably a load of anti-personnel or anti-tank mines 25 to 35 km away.

Wieczorek did at least hedge his bets with rockets by suggesting alternative and progressively more practical rockets instead of these. These included 120 mm to 150 mm rockets with a 15 km range, an unspecified ‘medium’ sized rocket for ranges up to 10 km, and ‘light’ LL11 40 mm to 60 mm calibre rockets for ranges between 3 and 6 km. Each rocket pod for these LL11 rockets would be able to hold between 15 and 20 rockets each, for a maximum of 30 to 40 rockets in total. These rockets were fitted all over the tank. The MLRS would go on the turret sides, more rockets of a large calibre in the armored side skirts on each side, a pod of light rockets in the front hull, and more within the sides of the turret.

Frontal cross-section of Wieczorek’s 1987 design showing the giant and somewhat ludicrous ‘ears’ on the sides for 6 or more rockets. Source: French Patent FR2613061

Seen with the MLRS pods removed, the cross section is still heavily laden with ammunition both internally, with the carousel, and with the various rockets on the turret sides and hull side skirt pods. French Patent FR2613061.

The likelihood of such an idea ever having been adopted, notwithstanding the good parts of his designs, is extremely low as it was just too complex. Adding another complex and heavy weapons system to a tank added nothing which a smaller investment in artillery could not accomplish. Certainly, the idea of the large MLRS rocket and the potential firepower it could add was tempting and Wieczorek speculated that such a system could be added to the sides of the German Leopard 2 or British Challenger tank. It is hard to imagine either wanting to add six of these 4 m long, 300 mm caliber rockets, each weighing 300 kg. Six of them would mean a minimum of 1.8 tonnes, not including any launch pod or control equipment. There was one further rocket module as well, containing between 100 and 200 50 mm to 70 mm calibre rockets in the space in the front, where there would usually be a driver. This would allow Wieczorek vehicle to deliver maximum possible firepower forwards at short range with additional small rockets. This too could simply have been omitted to reduce complexity, cost and weight, or replaced with something more useful, like more fuel to increase range. Had Wieczorek dropped these ideas for at least 2 tonnes of unnecessary encumbrance from the MLRS rockets alone, the weight savings could have been reused elsewhere on the tank or just left off to help reduce the weight. Dropping all ideas for these rocket pods would have simplified the design, made it cheaper, and also substantially lighter.

The well drawn but somewhat implausible turret-mounted MLRS pods could be elevated for launch when the turret was rotated. Note that the belly is fully lowered to the ground to reduce the profile of the tank. French Patent FR2613061.

Air Defence

The final firepower for the tank was a dedicated anti-aircraft gun of either 30 or 40 mm caliber and/or a pod for surface to air (SAM) missiles allowing for self-contained protection from enemy aircraft, including helicopters. This was yet one more thing adding unnecessary complexity and cost to the vehicle for a marginal benefit. These weapons were to be mounted in the back of the turret, as there was space available, having dropped the position of loader.

EBC Redux 1998 – the EBCL

Just a few years on from the original filing, the world had changed enormously, with the end of the Soviet Union and the utter destruction of Iraqi forces during the 1990/91 Gulf War demonstrating the enormous power of the modern MBTs over those even just a little older, like the T-72. Despite the T-72’s autoloader and the lack of such a device on the American M1 and British Challenger tanks deployed against them, it was an incredibly one-sided fight when it came to tank vs tank combat. Even Wieczorek’s consideration of substantially larger tank guns up to 140 mm was not in place and it could be argued that the British 120 mm rifled gun and the German 120 mm smoothbore on the American Abrams were more than adequate to deal with the Iraqi T-72s.

Nonetheless, work on a 140 mm gun had been taking place in Germany (now unified), the United Kingdom, France, and the United States. Wieczorek once more submitted for patent, in France and Poland, his idea for an ‘EBC’ – this time, however, the vehicle was larger and heavier with more suitable armament (no rockets). Yet, it was clearly an evolution of his earlier work – a culmination of a decades-long effort by him to create a tank better armed and armored than anything else at the time and suitable for up to 30 years of service.

With this in mind and an appreciation of the several or more years that it can take to get a tank design from drawing board concept to production and the cost of doing so, Wieczorek rightly saw that, for this concept to work, it would have to be adopted widely. This was not just going to be an idea for a giant French tank, but a giant tank that could be mass-produced and used by the members of NATO – grand ideas indeed.

Design of the 1998 Patent

Crew

In 1998, with the submission of the evolved EBC now an EBCL, Wieczorek stuck to his ideas of protective pods for the crew although this time all three crew were collated and all three were in the hull, a solution repeated decades later by the Russian T-14 Armata. This would greatly aid intercommunication between the men without the need for a video link although it was at the price of the commander being able to look out of the top of the vehicle.

The previous ideas of individual crew armored pods and of placing some crew members uncomfortably between the turret and the engine were gone. While the drawings show this crew compartment being in the front of the vehicle, Wieczorek mentions that this could have been put the other way around, with the crew in the back and the engine in the front.

In an effort to overcome the loss of awareness from detaching the crew from an elevated position, Wieczorek opted for an elevated observation periscope which could reach between 12 and 30 m high and fitted with a CCTV system and night vision equipment. The idea of a periscope would overcome some of that loss of situational awareness, as well as provide a significantly advantageous ability to see over obstacles or from behind cover. It would also mean that the gun could not be rotated past the periscope, hindering the ability of the tank to engage targets when the periscope was up.

Side mounted observation periscope. Note the single access door in the front lower hull. Source: European Patent EPO982560.

Seen from the rear, the EBCL shows how the periscope was fitted not to the tank hull itself but to the side armor module. Source: European Patent EPO982560.

Crew positions in the amended design of 1998, with the crew moved to the front in a separate pod. Crew seats are marked as ‘8’ and their control consoles as ‘12’. Source: French Patent FR2782789.

Plan view of the EBCL hull. Values are for the EBCL 1 and for the EBCL 2 (in brackets). Numbers 11,12, and 13 show the positions for the 3 crew in the front hull module. Note this drawing shows a single hull floor access hatch. Source: European Patent EPO98250302

Plan view of an alternative layout of the EBCL front hull module, showing the positions of the 3 crew as numbers 8, 9, and 10 respectively. Note the double front access doors. Source: French Patent FR2782789.

Protection

By 1998, these ideas for protection were not seen as being sufficient by Wieczorek, who was conscious of a new generation of Russian guns to surpass the older 125 mm guns, specifically mentioning a new Russian 135 mm smoothbore gun. To increase protection for the EBC, Wieczorek proposed the use of composite armor involving multiple layers of different types of steels, light metals, ceramics, and kevlar to provide roughly four times the protection available from just using traditional steel armor for the same weight. The disadvantage of this new armor was bulk and cost. Heavy protection from use of this new armor would be arrayed across the front of the hull and a similar level of protection across the front of the turret, in modules that could easily be replaced if they became damaged.

Seen in cross-section looking backwards from the front, the heavily protected crew space for the EBCL is readily apparent. Note that the side skirts are now simply referred to as side armor and all idea of mounting rockets in them has thankfully been removed. Source: European Patent EPO982560.

In order to provide as thick of an upper front aspect as possible, Wieczorek once more did away with a driver’s hatch. Unlike the 1987 ideas of sticking the driver in the back, now all the crew were in the hull and in the front of it, so he had to come up with a method of access to and from the tank for these men which would not compromise the frontal armor. The solution was to adopt a pair of rectangular belly plates behind the front armor and under the crew space. Additional changes to the 1986/87 concept was the use of Explosive Reactive Armor (ERA) on the hull, with special attention to the area between the hull and the turret for this armor.

Two views of the armor section on the front hull formed. The base armor is ‘31’, topped with a removable section of composite armor, of which the outer layer is indicated as ‘32’. The space between 31 and 33 is filled with composite layers of armor to suit requirements. Additional layers of armor can be laid over section 33. If required, ERA blocks ‘25’ could also be added. Source: French Patent FR2782789.

Even with the crew all together in a pod in the front of the hull, the use of bulky composite-type armor arrays provided a line of sight thickness of armor of between 1,200 and 1,800 mm.

Front aspect of the hull armor, with the Chobham armor array indicated by the ‘30’. Of note is that the floor armor is two layers with a small gap between them. Source: French Patent FR2782789

Two views of the front of the EBT both in 50 to 60 tonne form (solid outline) and 120 to 150 tonne form (dashed outline) showing the closed (left) and open (right) positions for the front hull access hatches. Source: French Patent FR2782789

By the time of the 1998 application, the weight had swollen faster than a cop on night shift near a doughnut shop. Gone was the 55 tonne ‘modest’ EBC, equivalent to other NATO tanks and a little lighter than some, and incoming was this new EBC at a mammoth 120 to 150 tonnes instead. At 120 tonnes, the EBCL would be ‘EBCL 1’ and at 150 tonnes ‘EBCL 2’. At this new weight, the EBC was now an Engin Blindé de Combat Lourds (EBCL) (English: a heavy armored combat vehicle).

With the switch to a front crew module Wieczorek retained the hydro-pneumatic suspension as shown here for the range of motion available. Source: French Patent FR2782789

Firepower

By 1998, the firepower, which was seen as adequate in 1987 in the form of a 120 mm smoothbore, was still adequate. However, as he discussed in his earlier patent application, he wanted a bigger gun. Somewhat thankfully, all attempts to clad the EBC as some form of mobile artillery were abandoned and the 1998 design featured no rockets at all.

Although the USA, UK, France, and Germany had all produced versions of a 140 mm smoothbore, the existing NATO tanks were not well suited to fitting them due to size and weight considerations, as well as recoil management. For example, the 120 mm smoothbore, as used on the Leopard 2 and M1 Abrams, had a recoil force of around 80 tonnes – heavier than the tanks themselves. The recoil force from a 140 mm gun would be even more severe and Wieczorek saw that the solution was to effectively take his 1986/87 EBC concept and make it bigger and heavier to accommodate this new generation of bigger tank guns. In his final part of discussion of tank guns, Wieczorek postulated that should his ideas for scaling up a tank to this size take place, then there would be no reason to suppose guns could not go up to 155 mm for the tank or a tank-based howitzer, or even bigger, although even he seems to have sounded skeptical when he suggested 210 mm as a caliber. It has to be considered though just what would warrant such a move to such a huge gun, as no Soviet era or Russian contemporary tank could warrant such an upgrade.

Making the next generation of EBC 120 to 150 tonnes would solve this problem in the sense that there would be more room for the bigger gun and ammunition as well as the new armor weight carried. Wieczorek made no mention of some of the problems with an MBT of that size, like fuel consumption, or whether or not it could cross smaller bridges. He did, however, consider transportation in terms of a road trailer and rail flatcar, and mentions that some contemporary cargo planes can carry 120 tons.

Two side views of the EBC with a soldier stood at the front to indicate the size of the vehicle (Fig. 24). A turret roof mounted remotely operated machine gun turret is shown, as are the planned SAMs in the back in the turret. In the lower view, the crew are visible, seated in the front heavily armored module. Source: European Patent EP0982560

The EBCL was also going to be using shells of at least 140 mm caliber as well as surface-to-air missiles (SAMs) fitted in the turret rear. All of these shells and missiles would be bulky and heavy, meaning that some assistance was going to be required to replenish ammunition. Wieczorek details some assistive measures for ammunition resupply.

The first of these measures is a dedicated resupply vehicle with a manipulator arm. This arm would take the weight of the SAM and lift it to the height of the turret, whereupon the large side armor would hinge forward, revealing a supply port into which the missile could be loaded.

Ammunition resupply for the SAMs in the turret assisted by a manipulator arm vehicle. Source: European Patent EP0982560

By having a closed-off system for the gun and ammunition to keep it apart from the crew, the vehicle gained valuable protection, but it also meant ammunition resupply by the crew would be difficult. The turret was, afterall, crewless, so there would be no manual loading of shells into the turret to then pass down into the carousel. Instead, Wieczorek solved the problem and substantially reduced the burden on the crew by simply accessing the ammunition supply from the side.

The side armor panels on the EBCL could be removed so that ammunition could be loaded directly into the carousel from the side. Source: European Patent EP0982560

For the new tank, Wieczorek, somewhat confusingly, switches his ammunition types. He sticks to the APFSDS and HEAT shells, but no longer are these unitary rounds. No longer too are these angled downwards and inwards to further reduce the width they take up. Instead, the drawings show the ammunition, once loaded into the side, being two-part with a seperate propellant charge stacked on top of the ammunition part, all on a horizontal carousel. These were to be 140 mm or 155 mm rounds and it is possible he was simply trying to show a semi-artillery type of gun, where the amount of propellant could be varied to vary the range, or that he was trying to simplify the design. Whichever was the case, in doing so, he also removed one of the key advantages of his own design in moving back from unitary rounds. This would lead to a shorter APFSDS penetrator and this would drastically affect anti-armor performance.

The outline drawings of the EBC with the front crew pod from European Patent EP0982560 include dimensions of the vehicle, which reinforces the enlarged dimensions of this 100+ tonne tank. The front crew pod alone was to measure between 3.5 and 3.6 meters long measured from the front of the nose to the back of the module. The top of the hull was calculated to be 2.1 m high and, with the turret, a total height of up 3.65 to 3.8 meters, depending on which version of EBCL was going to be built. Ground clearance was good for a tank as well, with 0.5 m between the ground and the belly plate, which could obviously be reduced by use of the hydro-pneumatic suspension. At the lower end of the weight class ~120 tonnes, the tank (EBCL 1) would have a ground contact length of 7 meters and, at the upper weight ~150 tonnes (EBCL 2), a length of 7.2 meters.

EBCL during loading on a 5-axle heavy trailer and showing the prospective dimensions. Source: European Patent EP0982560

Transport

As mentioned previously, it is width – specifically rail width, which is the dominant limiting factor for tank dimensions. When the EBC swelled from the 55-tonne range to that theoretical 120 to 150 tonnes, it did not just get heavier – it got larger too. Too large, in fact, to fit as a standard load on a rail car and awkwardly large for road transport.

Wieczorek did not ignore these issues and simply proposed moving the tank in separate pieces to reduce the individual load, somewhat ironically returning to one of the first problems to plague British tanks in WW1, where they were too wide to fit on rail cars and had to have the sponsons removed.

The solution was perhaps less grand than might be expected. It was simply to break the vehicle down into 3 modules: 1) the front crew module, 2) the central robotic and weapons module including the turret, and 3) the rear automotive module with the engine and transmission.

The three modules separated and together. This arrangement would not only make transportation easier, but also repair and maintenance. Source: European Patent EP0982560

Divided into 3 sections, A, B, and C, the EBC outline is surprisingly understated with a well sloped front. Note that the design, as drawn here, shows not only a coaxial and unidentified armament on the left side of the gun, but also the shape of the side skirts and that all 7 of the road wheels are of a uniform size and no side hull extension is used. Source: French Patent FR2782789.

The American HET (Heavy Equipment Transport) was made by Oshkosh and consisted of the M1070 tractor and M1000 semi-trailer unit. It provided long-range haulage on and off road for US Army equipment, including the M1 Abrams MBT. Weighing in at 41,000 lbs (18.6 tonnes) for the tractor and 50,000 lbs (22.7 tonnes) for the trailer, the HET had a combined unladen mass of 91,000 lbs (41.3 tonnes). Able to haul a maximum load of 140,000 lbs. (63.5 tonnes), the trailer used 5 sets of quadruple wheels for a total of 20 wheels to take the load. With a haulage limit of 63.5 tonnes, this would not be sufficient for Wieczorek’s new heavier tank, but he proposed a vehicle similar to the existing in-service HET, albeit modernized and with an extra axle with 2 wheels each side, for a total of 24 tyres instead of 20.

M1 Abrams MBT on the M1000 semi-trailer and towed by the M1070 tractor. Source: FAS.org

This was not the only change that would be needed to the HET trailer to move the EBCL. The side skirts on the hull and turret would also have to be removed at times for transport, so Wieczorek proposed a simple crane arm be added to the front of the HET trailer.

Modified HET trailer above with 5 axles and crane (top) and 6 axles (bottom). Note that the boxes under the crane are the maximum capacity and distance of the capacity of the arm. Source: European Patent EP0982560

Front and rear EBCL modules loaded onto a 5-wheel HET type trailer, showing the centres of gravity for each module. Source: European Patent EP0982560

The 65 to 75 tonne central EBCL module (5) and turret loaded onto a 5 axle HET type trailer, with the turret side armor sections removed and placed forward on the trailer (7) and the turret (6) turned sideways to align with the axis of the trailer. Source: European Patent EP0982560

Method of loading on three HET type trailers placed alongside each other. The tank simply drives over all three from the side, rotates the turret to the side and then the tank is split into its three modules. Source: European Patent EP0982560

For haulage by rail, a special rail car with a lowered central portion and two 4-axle bogies would be used, with the platform suspended between the two bogies, similar to the rail car designed for the German Maus. Much like the HET-type trailers for road transport, Wieczorek saw a relatively simple method for loading the tank onto both road trailers and also railcars. For transport, three HET-type trailers or rail cars would be placed alongside each other and the tank loaded on from the side to straddle all three trailers or cars. The track would be broken and the three modules separated. This method obviously would make loading and unloading tanks (reversing the process) easier where large flat hard surfaces, like car parks (for the HET trailers) or railheads with three parallel lines of track were available. Where they were not, life would have been significantly more difficult.

Shown on an 8-axle special rail car, the heavy EBC is shown in sections, having been loaded onto the lowered part of the rail car. The solid line is the conventional 50-ish tonne EBC and the dotted line showing the outline of the 120 – 150 tonnes heavy EBC. Source: European Patent EP0982560

Conclusion

If the 1986/87 EBC was not a sufficient step-change in design for a tank, then the 1998 EBCL was a leap into a future where a military budget for a giant tank might once again exist. The designer himself, Julien Wieczorek, is a bit of an enigma, leaving a long legacy of well-thought-out and carefully considered patents on a wide variety of civil and military engineering topics.
The EBL from the late 1980s shows a level of out-of-the-box thinking which is extravagant enough to solve that critical problem of a unitary ammunition carousel loader. It was also an idea sufficiently grounded that it is not hard to see it legitimately considered at a time of the Leclerc being prototyped.

The respawning in the post-Cold War of the idea is perhaps less clear in its reasoning. Certainly, before, the prevailing threat to Western Europe was Soviet aggression, so considerations of tanks capable of delivering a level of firepower never seen before on a tank was somewhat understandable. Post Cold War such a tank would be hard to comprehend and although the idea of strapping MLRS rockets to the sides of the turret disappeared, Wieczorek doubled down on his design in other regards. At a time when many nations were scaling back their tank fleets, with the Soviet Union now gone, Wieczorek instead planned for a tank bigger than any other in service, armed with a gun far larger too. The logistical burden of such a huge tank, whether 120 to 150 tonnes in weight, was answered in part by his novel ideas for transporting it on trucks and rail cars in modules. Certainly, the idea of an autoloading 155 mm heavy main battle tank has some appeal, but in drawing it, he also sacrificed the whole point of making the carousel in the first place. With the width issue resolvable by means of module transport, such a complex system would not be needed and why he would then choose to go back to a two-part ammunition system is likewise unclear. If width was solved by just breaking the tank down into 3 parts, why not just make the tank wider and fit it normally without the extensions.

There were other problems too. The periscope for visual assistance would obstruct the turret traverse – something which could have been easily resolved by putting it on the turret. The front crew access hatches reduced the frontal protection of the tank and provided access in a very awkward location – one which in a hull down position with the hydropneumatic suspension employed would actually trap the crew.

Nonetheless, Wieczorek worked hard to come up with realistic, if perhaps impractical ideas and his goal was clear – a big, more powerful and safer tank, and a really thorough consideration of how to reload, move, and operate such a machine. None of his designs came to fruition. The French adopted the Leclerc MBT and no armies in the year 2000 were looking for a 120 tonne, let alone a 150 tonne MBT.

The EBC was the sanest of Wieczorek’s designs, featuring an interesting autoloader in the hull which projected between the tracks. Illustration by Yuvnashva Sharma and funded by our Patreon campaign.

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Wieczorek EBC/EBCL Tanks specifications
	EBC	EBCL 1	EBCL 2
Crew	3	3	3
Weight	50 – 60 tonnes	120 tonnes	150 tonnes
Armament	120 mm smoothbore Rockets SAMs	120 – 140 mm smoothbore SAMs	140 – 155 mm smoothbore SAMs
Length		10.5 m	10.8 m
Width		5.5 m	6.4 m
Height (hull)		2.6 m	2.7 m
Height (total)		3.65 m	3.8 m
Ground Clearance		0.5 m	0.5 m

Cold War French Prototypes Has Own Video

Chasseur de Char de 76.2mm AMX sur châssis S35

Post author By Marisa Belhote
Post date September 10, 2021
7 Comments on Chasseur de Char de 76.2mm AMX sur châssis S35

France (1945)
Tank Destroyer – None Built

Following the liberation of France, which started in June 1944 and was mostly concluded, with the exception of areas towards Alsace and some western ports by the end of August that same year, rebuilding France’s military industry quickly became a new priority for the French government. Once a world leader, the French military industry had been considerably weakened by years of German requisitions and Allied bombings. If France wanted to retain an important and independent place on the world stage, a healthy military industry would prove a massively useful tool.

The first phases of the French military industry getting back on its feet often took the basis of pre-1940 vehicles being modernized to suit modern needs (such as the Panhard 178B, the first armored fighting vehicle produced by France post-war) or used as the basis for vehicles swaying away from the original hull’s role. Within these, one could name three tank destroyers projects which were submitted by the Atelier Mécanique d’Issy-Les-Moulineaux (AMX) in November 1945, mating the hulls of two pre-1940 French tanks, the R35 and S35, with the British 17-pounder anti-tank gun.

A ¾ front view of the S35 tank destroyer, showing the general shape of the casemate, driver’s hatch, and the large rear ammunition locker. Source: Mémoire des hommes

AMX’s proposals

There were three different proposals for 17-pounder-armed tank destroyers based on old French hulls. Two were based on the Renault R35 hull, one with a front-facing, and one with a rear-facing gun. These both dated from 8th November 1945. The third project actually predates both, with two documents, a ¾ top view of the vehicle dated from 11th October 1945, and a set of plans dated from 10th October.

As for the choice of the old French tank hull, while a number of S35s were seized after the liberation of France, this number remained limited, and the project was most likely never seriously intended for production. Instead, it likely was a ‘proof-of-concept’ and a way for AMX’s engineers to get back into designing armored vehicles on the basis of familiar components. One could argue that, in comparison to the R35, the S35 would provide a more viable basis, being a larger vehicle more suited to mount a heavy gun the like of the 17 pounder.

Overall superstructure

A front view of the S35 tank destroyer, showing the offset gun, driver’s post, and location of the most important ammunition stowage. Source: Mémoire des hommes

Mounting the 17-pounder on the hull of the Somua S35 obviously required some major changes to the superstructure and hull, though perhaps more moderate than on the lighter and smaller base of the R35. In the case of the S35, pretty much the whole front section of the upper hull and turret would be removed in order to accommodate the 17-pounder and fighting compartment. However, the engine compartment and rear part of the hull would be kept pretty much unchanged.

Overall, removing the turret would free up 2,350 kg. A further 1,850 kg of upper hull armor plates would be removed as well, and an additional 200 kilos of equipment. With all of this removed, the Somua, before receiving any of the additional equipment, would go down from 20,000 to 15,600 kg.

In place of the previous front upper hull, a new large armored superstructure would be installed. This was a fairly high superstructure, though, at a maximum height of 2.25 m, the tank destroyer would overall be shorter than the S35 tank. This superstructure, however, retained a bulky and massive silhouette the tank would have lacked. To the front, the sides angled forward towards the gun, which was offset to the right of the hull. The weight of this armored superstructure would be 2,000 kg, which was a lot more than on the R35 proposals. Though this may partially be explained by the superstructure simply being, to an extent, larger, it was also likely better armored to an extent – though the vehicle’s armor protection would most likely still have been lower than on the S35, not even accounting for the open top.

A side cutaway view of AMX’s S35 tank destroyer, showing the considerable length of the vehicle, of which an ample proportion was represented by the barrel. Source: Mémoire des hommes

This new casemate housed the British 17-pounder anti-tank gun, one of the most powerful anti-tank guns fielded by the Allies during the Second World War. In the form mounted in the tank destroyer, it weighed 1,630 kg. The gun was installed quite far forward in the hull, so as to leave sufficient internal space between its breech and the engine compartment for the vehicle crew. As a result, it overhanged the front of the hull by a whopping 2.86 m, bringing the length of the vehicle to 7.93 m. This gun, placed far to the front, also brought the center of gravity forward by 0.48 m, or from about the middle of the fifth roadwheel from the front to about the middle of the fourth roadwheel from the front. The gun had a field of fire of 29° to the right, and 16° to the left. It could elevate to 22° and depress to -9°.

The vehicle featured a 250 kg rounded mantlet, similar to the two R35 proposals. Unlike those two, the larger size of the S35 hull meant there was little overhang of the casemate over the engine compartment; though the casemate featured a form of bustle which contained an ammunition locker. The engine was still basically free to access. The vehicle retained the same powerplant as a conventional S35, a Somua 8-cylinders 190 hp engine. However, the S35 tank destroyer would be somewhat heavier than the S35, with an estimated weight of 21,658 kg, which would have resulted in a power-to-weight ratio to drop to about 8.8 hp/tonne, and the vehicle could overall be expected to be somewhat less mobile than the original S35 tank.

Internal arrangement, ammunition stowage, and crew

The plans of the S35 tank destroyer, as with the two R35 projects, depict it with a crew of only two – a driver sitting on the left of the vehicle and given a vision hatch through the new armored superstructure, and a commander which would presumably also operate the gun all by himself. It is very unlikely such a crew configuration was actually intended to be used. More so than on the R35 projects, the armored superstructure of the S35 allowed for enough place to accommodate at least one, if not two, additional crewmen, which would be more than helpful to operate a gun such as the 17-pounder in optimal conditions.

A top view of AMX’s S35 tank destroyer, showing the internal space that would be allocated to the crew between the massive gun and the engine compartment. Though portrayed with two crewmen, it is likely the vehicle would realistically have had a larger crew. Source: Mémoire des hommes

Two different ammunition lockers were provided for the vehicle. One was located to the right of the driver, below the gun’s breech, and accommodated 24 shells. A larger ammunition rack was installed in a form of bustle formed by the armored superstructure towards the rear, which would contain 54 shells. Finally, four shells would be stored on each side of the armored superstructure to form ready-racks, giving the vehicle a total ammunition carrying capacity of 86 rounds – or 1,978 kg of ammunition, to which one may add 200 kg for the weight of the ammunition locker and racks. This meant that firing all of the vehicle’s ammunition would considerably lighten it up, by more than 9%. This was not, however, as impressive as the front-facing R35 tank destroyer proposal, which would lighten up by around 13% after firing all of its ammunition.

Conclusion – Not a way you want to use a Somua’s hull

This S35 project could be argued to be the most reasonable and realistic design out of the three which were proposed by AMX’s engineers in late 1945. This was simply due to the fact the larger S35 hull would provide a far more viable basis for a large anti-tank gun such as the 17-pounder in comparison to the R35 hull, which would struggle to accommodate such a gun in a way that would make its operation viable. Nonetheless, it remained an obsolete concept. A fairly slow, not amphibious nor airborne, open-topped tank destroyer would have served as an anachronism in the post-war battlefields, had it been chosen for production. This would not, however, be the case, with the few remaining Somua S35s in French hands continuing their service as cavalry tanks until 1946 in the 13ème Régiment de Dragons, and even as gendarmerie vehicles for some years in French North Africa.

Wargaming’s S35 CA, fictionally armed with a 90 mm gun. Source: youtube

The Somua S35 tank destroyer would likely have remained an obscure project in the archives of AMX, were it not for its introduction in Wargaming’s World of Tanks as the “S35 CA”. Even for what was only a blueprint, the vehicle could be modified by the player into an ahistorical configuration there, by replacing the 17-pounder by a 90 mm anti-aircraft gun. From the start, the vehicle is also powered by the 220 hp engine intended for the S40, and is later given a so-called “S40 Bis” 260 hp engine. This is also wrong compared to the historical configuration of the vehicle, and was obviously added as a gameplay element, disregarding the historical project – a pretty systematic policy for Wargaming, which many other French paper projects, the likes of the AMX-40, have suffered from as well.

The AMX S35 tank destroyer in a fictional French post-war scheme. Illustration created by Pavel “Carpaticus” Alexe on the basis of work by Tank Encyclopedia’s own David Bocquellet

Chasseur de Char de 76.2mm AMX sur châssis S35 specifications
Dimensions (L x w x h)	7.93 x 2.05 x 2.25 m
Weight in battle order	21,568 kg
Engine	Somua 8-cylinders 190 hp engine
Power-to-weight ratio	8.8 hp/ton
Armament	17-pounder anti-tank gun
Ammunition stowage	86 rounds
Crew	Uncertain (a driver and commander for sure; likely a loader, perhaps a gunner)
Gun traverse	16° to the left, 29° to the right
Gun elevation	+22 to -9°

Sources

Cold War French Prototypes

Chasseur de Char de 76.2mm AMX sur châssis R35 (Front-Facing Proposal)

Post author By Marisa Belhote
Post date August 18, 2021
2 Comments on Chasseur de Char de 76.2mm AMX sur châssis R35 (Front-Facing Proposal)

Illustration for the Chasseur de Char de 76,2mm AMX sur châssis R35 (front-facing proposal), created by Pavel "Carpaticus" Alexe based on work by Tank Encyclopedia's own David Bocquelet

France (1945)
Tank Destroyer – None Built

The liberation of France began in June of 1944 and was mostly concluded, with the exception of a few areas towards Alsace and some western ports, by the end of August of the same year. Rebuilding France’s military industry quickly became a new priority for the French government. Once a world leader, the French military industry had been considerably weakened by years of German requisitions and Allied bombing. If France wanted to retain an important and independent place on the world stage, a healthy military industry would prove a massively useful tool.

The first phases of the French military industry getting back on its feet often took the form of pre-1940 vehicles being modernized to suit modern needs (such as the Panhard 178B, the first armored fighting vehicle produced by France post-war), or pre-1940 hulls being modified to fit roles other than fighting tanks. Within these, one could name three tank destroyers projects which were submitted by the Atelier Mécanique d’Issy-Les-Moulineaux (AMX) in November of 1945, mating the hulls of two pre-1940 French tanks, the R35 and S35, with the British 17-pounder anti-tank gun.

A ¾ front view of the front-facing proposal with an upward angle. On the left is a view of the front of the casemate, where the gun would be inserted. Source: Mémoire des hommes

AMX’s proposals

There were three different proposals for 17-pounder-armed tank destroyers based on old French hulls. One was designed on the S35 hull, and used a forward-firing gun. Two were designed on the R35 hull, one with a forward-facing gun and more ammunition stowage at the cost of being nearly a tonne heavier, and one with a rear-facing gun and more limited ammunition stowage, but about a tonne lighter. Both R35-based projects are dated from 8th November 1945, and as such, it is impossible to estimate whether one precedes the other.

As for the choice of the old French tank hull, only a small number of R35s were seized after the liberation of France, and the project was most likely never seriously intended for production. Instead, it likely was a proof-of-concept and a way for AMX’s engineers to get back into designing armored vehicles on the basis of familiar components.

Overall superstructure

Fitting the 17-Pounder into the diminutive hull of the R35 required some major changes. The gun would require a large, preferably open-topped casemate to be operated in decent conditions. In order to accommodate for this, pretty much all of the upper hull, as well as obviously the turret, was removed, and replaced by a thin, open-topped superstructure. This superstructure had simple, somewhat curved shapes, outside of the rear plate, which was pretty much flat. The superstructure narrowed down, extending towards the front to match the gun’s barrel. The armored superstructure had an overall weight of exactly one tonne or at least was planned as such by AMX’s engineers. Interestingly enough, when taking only the superstructure into account, the vehicle would be lightened by the removal of the turret and upper hull, which freed up 2,860 kg.

A front view of the front-facing R35 tank destroyer, showing the hatch which had been cut into the simple-shaped superstructure for the driver as well as the general, very basic silhouette of the vehicle. Source: Mémoire des hommes

The armor thickness of this casemate is unknown but was likely very thin. The front rounded part extending forward was cast. The rest was welded, with the exception of the rounded corners, which were cast pieces assembled to the rest via welding. The R35 was fairly diminutive in terms of size, and the casemate would cover pretty much the entire hull – the engine compartment was also entirely located under the casemate, which would highly complicate the maintenance of the tank’s powerplant.

This new casemate housed the British 17-Pounder anti-tank gun, one of the most powerful anti-tank guns fielded by the Allies during the Second World War. This gun had a large breech and considerable recoil, which is why a particularly large casemate would be needed in order to operate it from the hull of the R35. This obviously changed some of the vehicle’s dimensions. From 4.02 m, the vehicle would be extended to 6.64 m, while it would reach 2.10 m in height instead of 1.92 m, and be near this maximum height over a larger part of the vehicle. The large casemate dramatically increased the silhouette of the R35. This also changed the vehicle’s center of gravity, though a lot less with the full ammunition load, unlike the rear-facing version. However, the front-facing vehicle had a higher ammunition load, meaning expending it all would modify the center of gravity, bringing it forward by the length of more than half of one of the vehicle’s two bogies.

A cutaway side view of the R35-based tank destroyer, also showing the mounting of the mantlet on a frame. Source: Mémoire des hommes

The gun was placed through an armored mask and aimable frame. A thick cast mantlet was also found protecting this armored frame and the recoil cylinder of this gun and was attached to the rest of the casemate by a frame with several mounting points. This orientable frame would give the gun a lateral traverse of 21° to each side, identical to the other R35 tank destroyer proposal. Maximum elevation would be +20°, and depression -9°.

The tank destroyer would retain the same engine as the R35, meaning a Renault 447 4-cylinders engine producing 85 hp. However, the front-facing tank destroyer would add some considerable weight to the R35, which would rise from around 10.6 tonnes (up to 11 battle-ready) to 11.91 tonnes. This would further reduce the vehicle’s already mediocre power-to-weight ratio, going from 7.7 to 7.1 hp/tonne, likely reducing the R35’s already imperfect off-road mobility and an anemic maximum speed of 20 km/h even further.

Internal Arrangement, ammunition stowage, and crew

A top view of the vehicle, showing its internal arrangement and gun traverse. With the driver sitting right below the breech, some amount of space could perhaps house a third crew member remained within the hull. Operating the 17-Pounders gun alone while also commanding the driver would have been a herculean task to a single crewman, to which not even the overtasking of the B1 Bis’ commander could compare. Source: Mémoire des hommes

In the plans that were submitted by AMX, the R35-based tank destroyer is depicted with a crew of two, as on the original R35. It is unclear whether the vehicle was intended to be sent into operation with this tiny crew, way insufficient to reasonably operate a powerful gun firing a heavy shell such as the 17-Pounder, or if a third crewman would perhaps be present, and was just not included in the schematics. This would perhaps be accomplished seeing the size of the vehicle’s combat compartment but would make it a lot more cramped.

The driver retained the same position as on the R35, meaning he was located at the vehicle’s front, to the center. In this proposal, this made him sit right under the massive breech of the 17-Pounder anti-tank gun, meaning care would be needed in order to enter and exit his position quickly without hitting his head on the gun – particularly if it was orientated to the right. A hatch appears to have been cut through the new armored superstructure, which could be opened when not under fire. It could likely feature some form of episcopes to retain some vision while closed.

The gun was located to the vehicle’s front, with the rear of the breech roughly in the same position the turret would have been on a normal R35. Ammunition for it would be located to the rear of the fighting compartment. A large ammunition locker containing 58 rounds was located in a bustle on the rear of the casemate, extending over the engine compartment. A further 12 rounds were carried in a locker in the floor, just in front of the engine compartment’s bulkhead. This meant the vehicle would have a total of 70 rounds of ammunition at its disposal or 1,610 kg of 17-Pounder ammunition. If it fired all of its ammunition, the tank destroyer would lighten up by more than 13%.

Conclusion – An overly ambitious French Marder

This R35-based project was not the first project aimed at mounting a heavier gun on the basis of a French pre-1940 hull. During the war, several German conversions took the hulls of FCM 36 light tanks or Lorraine 37L armored tracked tractors to create tank destroyers armed with the 7.5 cm PaK 40 anti-tank gun, creating two conversions both referred to with the “Marder I” designation.

However, these generally used larger hulls and a gun still somewhat smaller than the massive British 17-Pounder. Mounting this large and heavy gun onto the small and diminutive hull of the R35 – with a significant ammunition stowage of 70 rounds no less – was an overly ambitious prospect, with the hull likely being, simply, too small and underpowered to produce a reasonably effective tank destroyer. By the time they were presented in November of 1945, the R35-based 17-Pounder tank destroyers would have been hopelessly obsolete. Limited-traverse-gun, open-topped tank destroyers were far outclassed by decently armed medium tanks by this point in general, and the vastly underpowered nature they would have had from the R35 chassis meant the tank destroyer would have been of little to no effectiveness in a modern, post-WWII battlefield. The French were very likely aware of this though, and it does not appear AMX’s proposals were ever seriously considered for production or even prototype construction. They were little more than training exercises for AMX’s engineers to get back in the field.

Illustration for the Chasseur de Char de 76.2mm AMX sur châssis R35 (front-facing proposal), created by Pavel “Carpaticus” Alexe based on work by Tank Encyclopedia’s own David Bocquelet

Chasseur de Char de 76.2mm AMX sur châssis R35 (front-facing proposal) specifications
Dimensions (L-H-W)	6.64 x 1.85 x 2.10 m
Weight in battle order	11,910 kg
Engine	Renault 447, 4-cylinders gasoline producing 85 hp
Power-to-weight ratio	7.1 hp/ton
Armament	17-Pounder anti-tank gun
Ammunition stowage	70 rounds
Crew	Either 2 (driver, commander/gunner/loader) or 3 (driver, commander/gunner, loader)
Gun traverse	21° to each side
Gun elevation	+20 to -9°

Sources

Archives du Service Technique de l’Armée via Mémoire des Hommes
Char-français
Tous les blindés de l’Armée Française 1914-1940, François Vauvillier, Histoire & Collection editions

Cold War French Prototypes

Chasseur de Char de 76.2mm AMX sur châssis R35 (Rear-Facing Proposal)

Post author By Marisa Belhote
Post date July 23, 2021
No Comments on Chasseur de Char de 76.2mm AMX sur châssis R35 (Rear-Facing Proposal)

Illustration of the rear-facing AMX R35 tank destroyer in an hypothetical camouflage of the French army towards 1945, created by Pavel "Carpaticus" Alexe and funded by our Patreon campaign

France (1945)
Tank Destroyer – None Built

A ¾ rear view of the R35-based tank destroyer from an upward angle, showing the very simple and clean-looking casemate, with only the engine compartment being truly recognizable from the old hull of the R35. Source: Mémoire des Hommes

AMX’s proposals

There were three different proposals for 17-pounder-armed tank destroyers based on old French hulls. One was designed on the S35 hull, and used a forward-firing gun. Two were designed on the R35 hull, one with a forward-facing gun and more ammunition stowage at the cost of being nearly a tonne heavier, and one with a rear-facing gun and more limited ammunition stowage, but about a tonne lighter. Both R35-based projects are dated from the 8th November 1945, and as such, it is impossible to estimate whether one precedes the other.

As for the choice of the old French tank hull, while a number of R35s were seized after the liberation of France, this number remained limited, and the project was most likely never seriously intended for production. Instead, it likely was a proof-of-concept and a way for AMX’s engineers to get back into designing armored vehicles on the basis of familiar components.

Overall superstructure

A rear view of the R35-based tank destroyer, showing the larger silhouette caused by the casemate, which outside of the gun’s mask, had very simple welded shapes. Source: Mémoire des hommes

This R35-based tank destroyer made major changes to the original vehicle, which would be needed to accommodate a gun as large as the British 17-pounders. The upper hull and turret were completely replaced by a new, much bigger open-topped armored superstructure. The removal of the turret and upper hull would free the tank of 2,860 kg, with the new superstructure – on its own – only weighing 800 kg. This small weight was likely accomplished by a very thin construction. The casemate was open-topped, though it reached high enough for a crew member standing on the vehicle’s floor to not stick out of the vehicle from a point of view at the same level of the vehicle, which would mean the vehicle would not be as vulnerable to firearms as other open-topped designs. However, it would also massively increase the silhouette of the R35. The casemate peaked at 2.17 m, in comparison to the R35’s 1.92 m.

The casemate mostly used welded construction. However, rounded corners as well as the rear section where the gun was located were cast instead. This formed a bulbous shape extending towards the barrel’s direction. The vehicle used the British 17-Pounder, one of the more powerful anti-tank guns fielded by the Allies during the Second World War. When facing the rear, the gun would need to be placed pretty far rearward in order to offer sufficient space to be operated properly within the casemate. This meant that this casemate extended rearward on top of the engine compartment, and the gun obviously extended further towards the rear. The overall length of the R35 was extended from 4.02 m, counting only the hull, to 6.22 m counting the 17-Pounder. The vehicle’s configuration, with not only the gun but even the casemate somewhat extending over the engine deck, would likely highly complicate the maintenance of the R35’s powerplant.

A cutaway view of the project, showing the casemate’s extension on top of the vehicle’s engine compartment, as well as the large amount of space occupied by the 17-Pounder and its breech, and the changing center of gravity. Source: Mémoire des hommes

The 17-Pounder in itself weighed 1,630 kg in the form that was mounted in the R35 tank destroyer. This was mounted with a gun mask on a movable mount, all weighing 280 kg. This would allow for a lateral traverse of 21° to each side, an elevation of +22°, and a depression of -9°.

The tank destroyer would retain the same engine as the R35, meaning a Renault 447 4-cylinders engine producing 85 hp. The rear-facing tank destroyer version was planned to have a fairly similar weight to the R35 – only raising the weight from around 10.6 tonnes (up to 11 in running order) to 11.046 tonnes, with the power-to-weight ratio only being reduced from 7.7 to 7.6 hp/tonnes. To be fair, this was already quite little, with the R35 being generally a somewhat anemic tank, rated for 20 km/h (up to 23 km/h according to Soviet trials of a captured example).

The center of gravity of the tank would be somewhat modified by the changes. It would be brought a little higher up and towards the rear, going from around the third roadwheel and the height of the sitting driver’s knees to the front of the fourth roadwheel, and the height of the driver’s torso. This would, however, remain fairly reasonable.

Internal Arrangement, ammunition stowage, and crew

A top-down view of the R35-based tank destroyer, showing the crew positions. It is unclear whether a third crew member could be present, to the left of the gun, to support the commander, or if he would be on his own to operate the armament. Source: Mémoire des hommes

In the known schematics, the R35 tank destroyer is portrayed with two crew members. The driver retained the same driving position as the R35, meaning he would be located at the center of the hull. The other crew member portrayed would if he was the only one, operate the 17-Pounder gun and command the tank all on his own, unless the driver would leave his position in combat operations, or if a third crew member would be present – which appears somewhat realistic seeing the casemate’s dimensions – and was just not portrayed in the schematics.

The gun was located on the higher part of the casemate, with the breech located around the level of an average crewman’s neck. On its sides, in parts of the armored hull that advanced inward to form the shroud-type armor surrounding the gun, a ready-rack for 6 rounds was located on each side of the gun. A further ammunition locker containing 30 rounds was located on the left of the hull, below the gun and just in front of the engine compartment. In total, ammunition stowage would account for 966 kg (included in the planned 11,066 kg weight figure). If it had fired all of its ammunition, this R35-based tank destroyer would have lost more than 8% of its weight.

Conclusion – A poor Frenchman’s Archer

This R35-based 17-pounder tank destroyer was not the only tank destroyer design using the British gun in a rear-mounted fashion. This rear-faced configuration had, in theory, some advantages, notably the ability to retreat immediately after firing and had even been used in a French 1940 wheeled tank destroyer, the Laffly W15 TCC. The same configuration had been used by the British for the Self Propelled 17pdr, Valentine, Mk I, more often than not known as the “Archer”. The Archer, however, used a hull much more well-suited to the task of mounting a gun as heavy and large as the 17-Pounders – the heavier and longer Valentine hull allowed for a more reasonable, lower casemate to be mounted, while only the gun itself would stick over the engine deck. The vehicle also had a somewhat better power-to-weight ratio, and, an obvious advantage, was introduced earlier, in 1944, in a context in which most tanks were still more lightly armored than what a French project proposed in late 1945, and which would likely have required months to a year to enter service, would have had to face were an armed conflict to break out in this time.

Thankfully, the project was never adopted, and was, very likely, never seriously considered for adoption, to begin with. The poor quality of the R35 hull, already very discussable by 1940 standards, was very obvious post-war, and even fixed gun, open-topped tank destroyers had generally proven to be inferior to medium tanks equipped with potent anti-armor weapons. As such, the R35 and S35-based projects were likely shelved very quickly after being proposed. Nothing is known of them outside of the schematics which were submitted by AMX.

Illustration of the rear-facing AMX R35 tank destroyer in a hypothetical camouflage of the French army towards 1945, created by Pavel “Carpaticus” Alexe and funded by our Patreon campaign

Chasseur de Char de 76.2mm AMX sur châssis R35 (rear-facing proposal) specifications
Dimensions (L-H-W)	6.22 x 1.85 x 2.17 m
Weight in battle order	11,046 kg
Engine	Renault 447, 4-cylinders gasoline producing 85 hp
Power-to-weight ratio	7.6 hp/ton
Armament	17-Pounder anti-tank gun
Ammunition stowage	42 rounds (12 in ready-racks, 30 in an ammunition locker)
Crew	Either 2 (driver, commander/gunner/loader) or 3 (driver, commander/gunner, loader)
Gun traverse	21° to each side
Gun elevation	+22 to -9°

Sources

Archives du Service Technique de l’Armée via Mémoire des Hommes
Char-français
Tous les blindés de l’Armée Française 1914-1940, François Vauvillier, Histoire & Collection editions

Cold War French Prototypes Has Own Video

Voisin CA 11 Amphibious Light Tank

Post author By Marisa Belhote
Post date March 8, 2021
2 Comments on Voisin CA 11 Amphibious Light Tank

France (1949-1953)
Amphibious Light Tank – 1 Prototype Built

Immediately after the conclusion of the Second World War, France found itself embroiled in a large-scale guerilla war in its colony of Indochina as it attempted to reassert control over the area. Seeking to overthrow their colonial rulers was the Vietnamese Việt Minh, led by Hô Chi Minh, as well as associated Laotian and Cambodian movements.

The French colony of Indochina map with its various territorial subdivisions: Cambodia, Laos, Cochinchina, Annam and Tonkin. Source: croiseur-lamotte-picquet.fr

Indochina was a particular theater that was characterized by a large number of swamplands and jungles, particularly along the Mekong Delta in the south of the country and the Hong River in the north. This type of terrain was particularly hard to operate in for French armored vehicles, particularly wheeled armored cars like the Panhard 178B or the British Coventry Armored Car, but even for tracked vehicles, such as the American M8 Scott or M24 Chaffee. Tracked amphibious vehicles were an obvious answer as to how to bring armored firepower into swamplands and rivers; however, by 1949, France was yet to have any of those vehicles in its inventory. While the USA had a potential answer in the form of the LVT-4 amphibious assault vehicle and its assault version, the LVT-4(A), the acquisition of such vehicles by the French had yet to be negotiated.

A Panhard 178B armored car in Indochina. Though armored cars were quite useful for patrolling roads, the limitations of such vehicles in rice paddies or swamps are obvious. Source: char-français

Setting requirements for an anti-guerrilla amphibious tank

On the 18th of January 1949, as the Indochina War had been raging on for more than three years by that point, the French EMA (Etat Major des Army – ENG: Army Headquarters) requested from DEFA (Direction des études et fabrications d’armement – ENG: Direction of Armament Studies and Manufacturing), the service in charge of directing France’s military research and production a light amphibious tank to be used in Indochina and, generally, in France’s colonies and overseas territories. Those other colonies and territories included Equatorial and Western Africa, and French Guyana – all places which would also benefit from the use of amphibious light tanks. This vehicle was desired to weigh not more than 11 tonnes, offer good off-road performance, particularly in swampy terrain, and mount a 75 mm howitzer in a turret.

Voisin/SNECMA’s proposal

On the 25th of April 1950, the Voisin branch of the state company of SNECMA accepted to design a vehicle for the light amphibious tank requirements, as well as to produce a scale model which would be used for floatation trials.

The Société des Avions Voisins (ENG: Voisin Planes Society) was, despite its name, more of a car-manufacturing company that had been founded by an aviation pioneer than an aircraft-manufacturing company. Founded in 1919, this company took the place of Aéroplanes Voisins (ENG: Voisin Aircrafts), an actual plane-manufacturing company that had manufactured a number of different aircraft for France’s aviation during the First World War. This included aircraft, such as the Voisin III to XI biplanes, which were notable for their pusher configuration.

The Société des Avions Voisins had, after the end of the Second World War, been incorporated first into the engine manufacturer Gnôme-Rhône, which was nationalized in 1945 to form the core of the state manufacturer SNECMA (Société nationale d’études et de construction de moteurs d’aviation – ENG: National aircraft engines study and construction society). Despite the Société des Avions Voisins being out of operations for five years by 1950, its name remained in occasional use for designs which were produced by what remained of its design bureau. This was the case of the CA 11 light amphibious tank; alongside a couple of other colonial amphibious projects from the same era, such as the CA 2 and CA 4 troop-transport tankettes, the CA 11 appears to have been Voisin’s sole foray into armored vehicles manufacturing.

The manufacturing of a scale model apparently went quite well, with an order for a mild steel prototype being made quickly. This prototype was manufactured in 1951-1952 and presented to the French military at Satory on the 20th of March 1953 for trials.

Voisin’s amphibious tank design

Voisin’s amphibious tank from a ¾ angle. Source: Les véhicules blindés français 1945-1977, Pierre Touzin, éditions EPA, 1978

The vehicle designed by the Voisin design team was a 12.5-tonne tank. Despite this light weight, the vehicle had fairly large dimensions, closer to a WW2-medium tank than a light tank, measuring 5.81 m long, 3.05 m wide, and 2.66 m high, with a ground clearance of 0.40 m. These large dimensions are likely a consequence of the vehicle’s amphibious hull design.

The fairly large hull of the Voisin tank bears some resemblance to the general shape of the LVT-4, likely due to some inspiration being taken from the American design. The boat-like hull shape optimized floatation capacity, with a bow striking out at the front, the drive sprockets being installed at its side, and, further back, a frontal plate angled backward. The suspension of the vehicle was relatively large, covering most of the hull’s side, in a fashion that can be reminiscent of vehicles such as the pre-war B1; such large suspension is typically installed to optimize all-terrain capacity. The suspension featured six fairly large road wheels at the bottom of the hull, as well as what appears to be a tender wheel at the rear. Three large box-shaped elements are located between the drive sprocket and tender wheels; the purpose of these may have been to improve floatation. The tracks were also clearly influenced by the LVT vehicles with a large curved grouser or spud on each link to improve traction is very soft ground as well as drive when negotiating water obstacles.

The engine, likely installed at the rear, was an air-cooled 8-cylinder, 10.857-liter unit producing 300 hp at 3,000 rpm, although it is not known whether it ran on petrol or diesel. This engine gave the CA 11 a very respectable power-to-weight ratio of 24 hp/ton; while the fuel consumption and capacity are unknown, the vehicle is known to have had a respectable range of 300 km. On road, the vehicle could reach a maximum speed of 54 km/h; on water, the maximum speed was 12 km/h. The CA 11 did not feature any hydrojet system; on water, its propulsion was assured by the tracks. These were 0.35 m wide, and appear to have used a flexible, most likely rubber construction. The armor layout of the vehicle is unknown, but the combination of light weight and fairly large dimensions of Voisin’s tank likely meant the armor was very thin, as typically expected of a counter-insurgency vehicle or amphibious tank. The crew configuration of the hull is also unknown; it may have had either merely a driver, or perhaps two crew members.

The SAGEM turret

A rear view of the Voisin CA 11, showing the flat rear of the turret’s basket. Source: Les véhicules blindés français 1945-1977, Pierre Touzin, éditions EPA, 1978

The Voisin CA 11’s turret was not designed by Voisin, but instead, by another company, SAGEM (Société d’applications générales d’électricité et de mécanique – ENG: Society of general electricity and mechanic applications). Although there is little detailed information on it, observing the few known photos of the CA 11 show the turret appears to have used a welded construction. To the left, a large commander cupola featuring a number of episcopes (perhaps 8) is located; another observation device can be found on the right-side. Though the crew configuration of the CA 11 is unknown, the turret generally appears to have been geared to house a two-man crew, with the commander to the left and the gunner to the right.

The main armament of the CA 11 was a 75 mm howitzer. Though the exact model is not specified in any source, the gun present on the vehicle shows many similarities with a 75 mm gun that was developed for the Panhard 178B, but never ended up used in the post-war model of the Panhard 178 armored car. This was a 75 mm gun based on the old 75 mm mle. 1897, shortened but firing the same shells with a lower velocity (though only by 15 m/s according to French documents). This gun was designated as the 75 mm SA 45. This gun was never known to have been mounted on a Panhard 178B prototype, and if it was actually the gun present on the CA 11, the Voisin amphibious tank may have been the first known vehicle to mount this obscure armament. It would have had the notable advantage of using the same ammunition as the 75 mm mle. 1897 – a mainstay of the French Army for decades, with large stocks of ammunition still in existence. That being said, while the CA 11’s gun appears visually similar to the SA 45, if it actually used this gun has not been confirmed. The vehicle’s ammunition stowage is unknown as well; it is, however, it is known that it used a 7.5 mm MAC31 as a coaxial machine-gun, likely on the right of the main gun.

Plans for the mounting of the 75 mm SA 45 in a turret, for the Panhard 178B armored car which ended up using the 47 mm SA 35 instead. This gun was likely the one used on the CA 11. Source: French military archives

Conclusion – Overtaken by the LVT-4

Voisin’s CA 11, though an interesting design for the challenges faced by France in Indochina, arrived way too late; by 1953, when the prototype was presented to the army, a solution had already been found to the problem of bringing armored firepower to the swamps and rivers of Indochina: The acquisition of American LVT-4s had been negotiated, with the first examples being delivered in 1950 – before the prototype CA-11 was even unveiled. While the CA 11 could arguably have filled a niche for the French if the American deliveries had only included machine-gunning armed examples it was rendered redundant as the American deliveries included 75 mm-armed LVT-4(A). The French themselves would eventually modify a number of the troop transport LVTP-4s to accommodate 75 mm recoilless guns or even turreted 40 mm Bofors autocannons.

With the presence of the LVT-4 in the French army, the procurement and production of the CA 11 would have been a costly and redundant affair. The Indochina War in general was, by that point, a costly and very unpopular affair in which France was embroiled, with no hope of quickly recovering the colony. With little enthusiasm for the idea of remaining involved in the region, France ended up pulling out in 1954, leaving, as far as possible, friendly local governments in place. The end of the Indochina war likely removed all enthusiasm for a colonial amphibious tank for a time although the LVT-4s which had been obtained were conserved. They went on to be used to form an amphibious assault school in Algeria and eventually being used during the Suez Crisis against Egypt in 1956. The Voisin CA 11 project was likely shelved indefinitely, marking an end to Voisin’s short foray into armored vehicles manufacturing. As for the manufactured prototype, its fate is unknown, but it very likely ended up scrapped.

French 40 mm-armed LVT-4s in rice paddies, Indochina. The use of the LVT-4 by the French army, including this local conversion performed by units in Indochina and retained in the following years, made the CA 11 redundant. As for the LVT-4, it would remain in French service until the 1970s.

Tentative side profile of the Voisin CA-11, as no side drawings or good side pictures exist. Illustration by Yuvnashva Sharma, funded by our Patreon campaign.

Specifications
Dimensions	5.81 m x 3.05 m x 2.66 m
Total weight, battle ready	12.5 tonnes
Crew	Likely 3 (driver, commander, gunner)
Propulsion	8-cylinder 10.857 litre air-cooled engine producing 300 hp at 3000 rpm
Range	300 km
Ground Clearance	0.40 m
Max. Speed (road)	54 km/h
Max. Speed (water)	12 km/h
Armament	75mm howitzer (perhaps 75mm SA 45) MAC 31 7.5 mm coaxial machine-gun
Power-to-weight ratio (in hp/ton)	24

Sources

Les véhicules blindés français 1945-1977, Pierre Touzin, éditions EPA, 1978
Char-français: https://www.chars-francais.net/2015/index.php/engins-blindes/engins-divers?task=view&id=103
https://www.chars-francais.net/2015/index.php/engins-blindes/engins-divers?task=view&id=680
https://www.chars-francais.net/2015/index.php/engins-blindes/engins-divers?task=view&id=102
French military archives at Châtellerault: Note pour la direction du matériel, N°28.750, 8 Juin 1945

France/Federal Republic of Germany (1955?-1961) Anti-Tank Reconnaissance Vehicle – 1 to 2 Prototypes Built

The Founding of the Bundeswehr

The Panzeraufklärungstruppe

The Schützenpanzer (Kurz)

The French SP. 1C

The German SP. 1C

The SP. 1C in detail

Hull

Mobility

Turrets

The French Turret

The German turret

Armament

Fate

A Mystery

Conclusion

Sources

France (1947-1951) Light Tank – 1 Prototype Built

A Resurgent Tank Industry

A French Tank on a German-Style Suspension

Continuing Evolutions toward a Prototype

Design

Hull

Power train

Suspension

Turrets

Weight Distribution and Expected Performances

Artillery Version

Prototype and Trials

Conclusion – Too Late to the Party

1947 interleaved road wheels design Specifications

Finalized design (1950) Specifications

Artillery version (1950) Specifications

Test vehicle (1950-1951) Specifications

Sources

France (1956) Tank – Patent Only

Novelty

The Man

The Tank Described

Armament

Entrenching

Conclusion

Giacomini Tank Specifications Giacomini Tank

Sources

France (1947-1952) Light Tank – 1 Prototype Built

Ambitions from Ashes

Design

The FCM 12t’s Hull

Powerplant and Suspension

Turrets

Artillery Version

Trials and Performances

Modifications

Conclusion – One of the last FCMs

FCM 12t specifications (configuration with the FL 4 turret)

France (1946) Tank Destroyer – None Built

Introduction

Overall Characteristics and Layout

Armament and Ammunition

Automatic Ejection and Loading Device

Protection and Survivability

Powertrain

Suspension

Mobility

Conclusion

AMX Chasseur de Char de 90 mm specifications

Sources

France (1986-2000) Main Battle Tank – None Built

The Man

Birth of the EBC 1986

Design of the 1986 Patent

Dimensions

Crew

Protection

Automotive

Suspension and Track

Armament

Ammunition Resupply

Autoloader

1987 – Rocket Armor!

France/Federal Republic of Germany (1955?-1961)
Anti-Tank Reconnaissance Vehicle – 1 to 2 Prototypes Built

France (1947-1951)
Light Tank – 1 Prototype Built

France (1956)
Tank – Patent Only

France (1947-1952)
Light Tank – 1 Prototype Built

France (1946)
Tank Destroyer – None Built

France (1986-2000)
Main Battle Tank – None Built

France (1945)
Tank Destroyer – None Built

France (1945)
Tank Destroyer – None Built

France (1945)
Tank Destroyer – None Built

France (1949-1953)
Amphibious Light Tank – 1 Prototype Built