The Autocannone da 102/35 su FIAT 634N was an Italian truck-mounted anti-aircraft and support self-propelled gun used by the Italian Milizia marittima di artiglieria (English: Maritime Artillery Militia) under Italian Regia Marina (English: Royal Navy) in North Africa against the Commonwealth troops.
It was built by mounting some 102 mm Regia Marina (English: Royal Navy) guns taken from anti-ship batteries on the African coasts on Royal Army heavy duty trucks.
They were divided in two batteries assigned to the 101ª Divisione Motorizzata ‘Trieste’ (English: 101st Mechanized Division) and the 132ª Divisione corazzata ‘Ariete’ (English: 132nd Armored Division).
Their service was limited but, thanks to their powerful gun, they were used successfully even against British armor. Autocannone da 102/35 su FIAT 634N means Truck-mounted 102 mm L/35 gun on FIAT 634N [chassis].
During the first stages of the Second World War, the Regio Esercito was involved in a military campaign against the Commonwealth troops in the vast deserts of North Africa. This campaign started on 9th September 1940, when Italian troops invaded Egypt from Libya, which was an Italian colony. During this action, it was clear for the Regio Esercito commanders in Africa that the army needed long range and well armed reconnaissance vehicles with great mobility. It also needed support vehicles armed with field guns capable of supporting Italian assault infantry units. These also had to be fast in order to move from one point to another on the battlefield, stopping the British assaults and supporting the Italian counterattacks.
For this purpose, some light trucks captured from the British troops in Cyrenaica during the first days of war were used. These vehicles were Morris CS8, Ford F15 and Chevrolet C15, all with a payload capacity of 15-cwt (750 kg). These trucks were captured in large quantities and were put back into service, with the Italian coat of arms, as supply trucks.
General Gastone Gambara, one of the Italian commanders in North Africa, ordered workshops to take some of these British lorries and modify them, mounting artillery pieces on their loading bay. This is how autocannoni appeared.
The word ‘Autocannone’ (Autocannoni plural) designated any truck equipped with a field, anti-tank or support gun permanently mounted on its cargo bay.
The first autocannone produced in significant numbers (24 vehicles) was the Autocannone da 65/17 su Morris CS8. This consisted of an old Cannone da 65/17 Mod. 1908/13 mountain gun mounted on the cargo bay of a Morris CS8 that was slightly modified stretching it by 50 cm. The gun carriage was modified, removing the spade and the wheels, and welding it on a Italian medium tank turret ring that allowed 360° traverse.
While the Morris CS8 was transformed into a support autocannone, the smaller Fords and Chevrolets were converted into anti-aircraft autocannoni, mounting a Cannone da 20/65 Mod. 1935 or Mod. 1939. These were used to defend the Batterie Autocannoni (English: Autocannoni Batteries) or the Italian supply convoys from aircraft strikes.
In North Africa, other autocannoni were produced with support, anti-aircraft or anti-tank guns on different types of trucks, mainly of Italian production.
The FIAT 634N Truck
In 1930, FIAT developed two heavy trucks, the 632N and the 634N. The letter N stood for ‘Nafta’, or diesel in Italian. These were the first two heavy duty diesel trucks made in Italy.
The 634N truck was officially presented to the public in April 1931, during the Milan trade fair. The 634N was the largest truck produced in Italy at the time, with a maximum allowed weight of 12.5 tonnes. It was nicknamed ‘Elefante’ (English: Elephant) for its robustness, power, and load capacity. Its production, in three versions, ran from 1931 to 1939.
After chassis number 1614, the wheel rims were replaced with ones with six spokes, made of cast steel. After strengthening the rear axle, the chassis, and the leaf springs, the vehicle could carry more weight, from 6,140 kg to 7,640 kg, thus reaching a maximum total weight of 14 tonnes, with an empty weight of 6,360 kg. These modifications gave birth to the FIAT 634N 2nd series or N1, which also had the front fenders connected to the bumper. The FIAT 634N1 was produced from 1933 to 1939.
In 1933, the FIAT 634N2 version was born, with a modified cab meant to increase aerodynamics, a drop-shaped radiator grille, angled windscreen, and more rounded shapes. The load capacity and speed remained unchanged compared to the N1 version. The FIAT 634N 2nd series or N2 was produced from 1933 to 1939.
This was the first truck in Europe to be equipped with bunks for the crew. The back of the seat could be raised to form two bunks and, on request, there was a modification available to provide a third bunk, lifting the roof of the cabin.
As an example, the second company to provide a berth in the cabin was Renault with its three-axle Renault AFKD, with a load capacity of 10 tonnes. This entered service only in 1936. The third was Lancia Veicoli Industriali with the Lancia 3Ro in 1938.
The wooden cargo bay was 4.435 meters long and 2.28 meters wide. The foldable sides were 0.65 meters high, with a maximum load allowed by law of 7.640 kg, while the maximum transportable weight did not exceed 10 tonnes. The lateral and rear sides were foldable.
On the N1 and N2 versions, it was possible to tow a two-axle trailer for the transport of materials, reaching a maximum weight allowed by law of the truck + trailer of 24 tonnes. During the war, the FIAT 634N successfully towed tanks of the ‘M’ series and self-propelled vehicles on the same chassis in the Rimorchi Unificati Viberti da 15t (English: 15 tonnes Viberti Unified Trailer).
Photos taken during the war, however, show very well that the truck could load much more. Some photos show the FIAT 634N towing trailers of 3,750 kg, with tanks of 13 tonnes or more in them, and in other materials the cargo bay. This would have brought the total weight of the truck + trailer to much more than 24 tonnes.
Most of the trucks received a cab from FIAT, but Officine Viberti of Turin and Orlandi of Brescia also built bodies for some chassis. The military version was called FIAT 634NM (Nafta, Militare – Diesel, Military), but its characteristics were almost identical to the civilian versions, with the main difference being a more rustic cab.
During the Second World War, due to the Royal Army’s need for logistic vehicles, a total of 45,000 civilian vehicles in Italy were requisitioned, overhauled, repainted, re-plated, and put back into service as military vehicles. This meant that not all of the FIAT 634s in the Italian military were NM versions, but there were also civilian ones.
The big difference between the civilian and military versions was the windows. In the military version, the truck had fixed windows, different headlights and lacked the triangular placard on the roof of the cab used in the civilian models to indicate the presence of a towing trailer.
Several variants were produced on this truck chassis. There were tanker versions for fuel or water, produced by Officine Viberti and SIAV, a mobile workshop composed of three different FIAT 634Ns which carried the necessary equipment to set up a fully equipped field workshop, at least two versions for the firefighters, a horse carrier version for the army, a sand truck with tipping platform, a gas version and three different Autocannoni.
These were the 102/35 su FIAT 634N and the 76/30 su FIAT 634N, with 6 produced by the FIAT workshops in Libya during the North African Campaign. In the Africa Orientale Italiana or AOI (English: Italian East Africa), some Autocannoni da 65/17 su FIAT 634N were produced in unknown numbers by Officine Monti in Gondar together with the Autoblinda Monti-FIAT on the same chassis.
The military version could carry up to 7,640 kg of equipment, although the maximum transportable weight came to almost 10 tonnes of ammunition, provisions, or almost 40 fully equipped men.
The cargo bay could comfortably carry an Italian light tank, such as the L3 or L6/40, or the Semovente L40 da 47/32 self-propelled gun. The Rimorchio Unificato Viberti da 15t could carru any tank of the ‘M’ series (M13/40, M14/41 or M15/42) and all self-propelled guns on their chassis.
Engine and suspension
The FIAT 634N was powered by a FIAT Tipo 355 diesel engine with six cylinders in line. It had a capacity of 8312 cm³, delivering 75 hp at 1700 rpm. This was developed independently by the company thanks to the experience gained with marine engines.
From the 1086 model onward, the engine was replaced by the FIAT Tipo 355C, with a capacity of 8355 cm³. The power was increased to 80 hp at 1700 rpm thanks to an increased bore and stroke.
The fuel distribution to the cylinders was ensured by overhead valves. These were fed by an injection pump located on the right of the engine. As on many other Italian trucks of the time, the 20-liter reserve fuel tank was mounted behind the dashboard and fed the engine by gravity. In case of a fuel pump failure or problems with the main tank, the truck could still drive a few kilometers before stopping.
A pump connected to the 150-liters main tank fed the reserve tank. The main tank was mounted on the right side of the chassis. Two small electric motors were used to start the Diesel engine. The 170 liters of fuel guaranteed a range of 400 km, while the maximum speed was about 40 km/h on road.
A dry multi-disc clutch was attached to the gearbox, with four-speed plus reverse gears. The suspension consisted of semi-elliptical leaf springs on the front and rear axles. Drum brakes were pedal-operated through three vacuum boosters.
The Cannone Schneider-Ansaldo da 102/35 Modello 1914 was an Italian 102 mm L/35 naval cannon developed from the British QF 4-inch naval gun Mk V. It was used on many types of Italian military ships and submarines in the anti-aircraft and anti-ship roles. It was also used as an anti-ship coastal gun. It was also produced for the Regio Esercito as the main gun of the Autocannone da 102/35 su SPA 9000, one of the first autocannoni ever, used by the Italians during the First World War.
While the performance of the cannon was not mediocre, it was not sufficient either. Thus, already during the First World War, it was joined by the more powerful Cannone Schneider-Ansaldo da 102/45 Modello 1917 and then substituted after the war by the Cannone Schneider-Canet-Armstrong da 120/45 Mod. 1918.
After the war, the gun was no longer produced but was used in other Italian warships such as the submarines of the ‘Argonauta’ series of the 600 class entered in service in 1932 and ‘Miraglia’ seaplane carriers entered in service in 1927. It remained on board the ships and submarines produced between 1914 and 1917.
When the Kingdom of Italy entered the Second World War in 1940, 110 102 mm guns were in service, equipping the anti-aircraft batteries of the Royal Army, the Milizia per la DIfesa ContrAerea Territoriale or DICAT (English: Militia for Territorial Anti-Aircraft Defense), the MILizia Marittima di ARTiglieria or MILMART (English: Maritime Artillery Militia) and of the Guardia alla Frontiera or GaF (English: Army Border Guard). In 1940, among the armed trains of the Regia Marina, the TA 102/1/T (Treno Armato – Armored Train) was mobilized, with two ‘P.R.Z.’-type railway wagons, each armed with three Cannone da 102/35 Mod. 1914 mm guns on Vickers-Terni mod.1925 mountings.
The gun had a caliber of 101.6 mm and the barrel was 3.733 meters in height. On the autocannone FIAT 634N, different types of trunnions were used, including the Ansaldo Mod. 1925, the O.T.O. Mod. 1933 and the Vickers-Terni Mod. 1925 even if photographic evidence shows only the last two variants.
The Vickers-Terni Mod. 1925 trunnion had an elevation of +90° and a depression of -5°. The O.T.O. Mod. 1933 had an elevation of +80° and a depression of -10° while the Ansaldo Mod. 1925 had an elevation of +85° and a depression of -5°. All the trunnions had a traverse of 360°.
The firing rate was 20 rounds per minute thanks to the vertical sliding breech block. When it was necessary to fire for a long period of time, the rate of fire was dropped to 1 round every minute or even 1 round every 4 minutes, in order not to overheat the barrel and not to tire the servants.
The vehicle had two ammunition racks on the vehicle’s rear, for a total of 36 rounds carried. The 102 x 649mm R rounds had a fixed charge with a total weight of about 25 kg. It is almost sure there were more types of ammunition but, unfortunately, there is no information available.
|Cannone Schneider-Ansaldo da 102/35 Modello 1914 rounds|
|Cartoccio Granata Dirompente||High-Explosive||13,427 kg|
|Cartoccio Granata Dirompente *||High-Explosive||13,750 kg or 13,650 kg|
|Navy Shrapnel **||Shrapnel||15 kg|
|Notes||* For anti-naval role but commonly use also by the autocannoni
** No longer in production but still used
Autocannone da 102/35 su FIAT 634N
The FIAT workshops of Tripoli, one of the biggest workshops in North Africa, modified two FIAT 634Ns between February and March 1941, adding two 102 mm guns taken from the Tobruk coastal batteries. In August, another vehicle was modified. The gun was taken from the batteries of Benghazi.
The other four vehicles were modified between April and July 1941 with cannons arriving from Benghazi and all were ready for October 1941. The trucks were modified by removing the cab roof, sides and the windshield in order to allow the cannon 360° traverse. The chassis remained unchanged.
In case of rain, the crew could protect themselves with a water-proof tarpaulin that could be opened and closed like on cabriolet cars. This tarpaulin was mounted on rods on the cab’s rear and did not obstruct the cannon’s arc of fire. The wooden cargo bay was completely removed and substituted by a steel platform on which the gun trunnion was placed.
The sides of the new platform could be lowered outward by 90° to give more working space on the platform to the gun servants when firing. On the rear, two metal racks with 18 rounds were mounted to the platform. On the racks was fixed a wooden bench where the servants and the gunner could sit during transport.
Due to the heavy stress generated by the gun’s recoil, the vehicle was equipped with four trails with manual jacks. These trails were attached to the chassis during the march. When the vehicle was placed in firing position, these were opened by 90°, a jack pad was mounted below and then the soldiers could lower the jack with a manual crank.
With the seven Autocannoni da 102/35 su FIAT 634N, the 1ª and 6ª Batteria (English: 1st and 6th Batteries) were created with crew members taken from the IIª Legione MILMART (English: 2nd MILMART Legion) and from the Vª Legione MILMART. On 1st June 1941 the Iª Gruppo Autonomo Africa Settentrionale (English: 1st North African Autonomous Group) was transformed in the Xª Legione MILMART and assigned to both the batteries.
Each battery was equipped with a Centrale di Tiro Mod. 1940 ‘Gamma’ or the improved variant, the G1. These were stereoscopic rangefinders mounted on FIAT 626 chassis (some sources claim that these trucks were armored, but nothing certain is known). Two FIAT 666NMs were also modified by the FIAT workshops in Tripoli and used as ammunition carriers. There were probably 2 for each battery section, for a total of 4 for each battery. Along with them were other logistics and close defense vehicles, but nothing is known about these.
The two batteries were first assigned to the Corpo d’Armata di Manovra or CAM (English: Mobile Army Corps) in the Marmarica region commanded by General Gastone Gambara on 20th October 1941.
The 1ª Batteria, with three autocannoni da 105/35, and the Sezione B (English: B Section) of 6ª Batteria, with two autocannoni da 102/35, were assigned on 26th October 1941 to the 132ª Divisione corazzata ‘Ariete’. Sezione A of 6ª Batteria, with two autocannoni da 102/35, was assigned on the same day to the 101ª Divisione Motorizzata ‘Trieste’.
The batteries were also equipped with a total of six Autocannoni da 76/30 su FIAT 634N armed with a Cannone da 76/30 Mod. 1914 R.M..
The autocannoni of the 132ª Divisione corazzata ‘Ariete’ were first used in an anti-aircraft role. They gave good results, although some had problems with the elevation mechanisms and stability problems.
Their first battle they took part in was the Battle of Bir el Gobi on 19th November 1941, where they were an unwelcome surprise to the British. The autocannoni were positioned in the second line and were used to engage some tanks of the 22nd British Armoured Brigade at long-range, knocking out or destroying fifteen Crusader tanks. On this occasion, the 102/35 guns engaged the enemy armored vehicles at a range of over 1000 meters with precision thanks to the rangefinders.
On that day, of 136 tanks of the 22nd British Armoured Brigade, 25 were lost (some sources claim 42, others 57), while the Italians lost 34 tanks. 12 others were damaged and 12 artillery pieces were also lost. The autocannoni of the Ariete division were lost during the skirmishes and fights that occurred between 21st November 1941 and 2nd December 1941. The first autocannone was lost on 25th November while another was abandoned, unusable at Dir el Abid on an unspecified date. The last one of the 1st Battery and the second of the Second Section of the 2nd Battery destroyed by air attack on 4th December 1941.
The autocannoni of the Sezione A of 6ª Batteria of the 101ª Divisione Motorizzata ‘Trieste’ were used in Tripolitania and took part in the offensive of May 1942 to recapture Tobruk.
The surviving vehicles were captured by the British troops at Tobruk in November 1942.
The Autocannone da 102/35 di FIAT 634N was one of the improvised vehicles produced by the Regio Esercito in North Africa, where the absence of adequate vehicles was problematic. Despite only seven being produced, the design proved to be viable, with excellent firepower capable of putting any British tank in North Africa in 1941 and early 1942 out of action.
Despite the few vehicles converted, the 102 mm autocannons did, on one occasion, change the fate of a battle in favor of the Italians.
|Autocannone da 102/35 su FIAT 634N specifications|
|Dimensions (L-W-H)||7.35 x 2.4 x ~3 m|
|Crew||6 (driver, commander, gunner and 3 servants)|
|Propulsion||Tipo 355 diesel, 6-cylinders, 8,310 cm³, 75 hp at 1,700 rpm|
|Armament||Cannone Schneider-Ansaldo da 102/35 Mod. 1914|
|Number Built||7 modified|
Gli Autoveicoli tattici e logistici del Regio Esercito Italiano fino al 1943, Tomo II – Nicola Pignato and Filippo Cappellano
Gli Autoveicoli del Regio Esercito nella Seconda Guerra Mondiale – Nicola Pignato and Filippo Cappellano
Italian Truck-Mounted Artillery – Ralph Riccio and Nicola Pignato
I Corazzati di Circostanza Italiani – Nico Sgarlato