Kingdom of Italy (1941-1942)
Self-Propelled Gun – 12 Converted
The Autocannone da 75/27 su FIAT-SPA T.L.37 was an Italian truck-mounted artillery Self-Propelled Gun (SPG). It was developed as a desperate solution to improve the mobility of an old artillery piece and to support the Italian troops in the North African Campaign.
It was used by the Italian Regio Esercito (English: Royal Army), with a dozen units assigned to three batteries of the XVI Gruppo Autoportato (English: 16th Truck-Transported Group) of the Raggruppamento Celere AS (English: North African Fast Group). After mid-1942, the surviving vehicles were assigned to the 136º Reggimento Artiglieria Motorizzata (English: 136th Motorized Artillery Regiment) of the 136ª Divisione Corazzata ‘Giovani Fascisti’ (English: 136th Armored Division).
Context
After the initial military success in the North African Campaign, such as the Italian Invasion of Egypt between 9th-16th September 1940 and Operation Sonnenblume (English: Operation Sunflower) between 6th February-25th May 1941, the Regio Esercito High Command noticed that their ranks were missing fast support vehicles equipped with powerful support guns.
They had two options. They could wait for some fully-designed vehicles from the mainland or produce some support vehicles locally by modifying Italian trucks present in the Italian African colonies.
The inadequacy of the Italian tanks, such as the L3 series light tanks and the medium M11/39 and M13/40 tanks, made evident in the fighting against British tanks, and the reduced mobility of the infantry medium and heavy support artillery in the desert, pushed the High Command to appeal to the Italian workshops in Libya to create vehicles for the role.
These had to be light and fast and be able to support the Italian infantry or armored units from short-to-medium ranges with guns that would normally have been towed. Such vehicles would have to be able to move quickly from one point to another on the North African battlefields, in order to engage the enemy forces that broke through the Axis defensive lines.
Obviously, this was seen by the Italian commanders in Africa as a temporary solution while waiting for the production of better armed vehicles with adequate characteristics. Such vehicles unfortunately never came in any significant numbers.
The Autocannoni da 75/27 su FIAT-SPA T.L.37s, like other autocannoni such as the Autocannone da 102/35 su FIAT 634N, were built at the Libyan workshops of the 12° Autoraggruppamento AS (‘AS’ stands for Africa Settentrionale – North Africa) situated in the village of Giovanni Berta, near the city of El Gubba in north-east Libya.
The Italian ‘Autocannone da 75/27 su FIAT-SPA T.L.37’ (Autocannoni plural) means “75 mm L/27 truck-mounted [cannon] on FIAT-SPA T.L.37 [chassis]” in English.
Design
The FIAT-SPA T.L.37
In the first half of 1935, the Regio Esercito issued a request for a new prime mover to tow the 75 mm and 100 mm guns and howitzers in the Italian Royal Army artillery units. It was meant to replace the old Pavesi P4/100 TL140, also known as the Trattore Leggero Modello 1931.
Army requirements included four-wheel drive for better off-road performances, a maximum speed of 40 km/h, and to transport six soldiers, including the driver. Only two Italian companies responded to the request: Fabbrica Italiana Automobili Torino or FIAT (English: Italian Automobile Factory of Turin), and Società Italiana Ernesto Breda per Costruzioni Meccaniche (English: Italian Ernesto Breda Company for Mechanical Constructions).
The model proposed by FIAT in collaboration with the Società Piemontese Automobili or SPA (English: Pedimontese Automobile Company), its subsidiary, was developed by the team of engineer Emilio Martinotti and was equipped with the Tipo 18 engine, already extensively used on the SPA Dovunque 35 medium truck and on the FIAT-SPA 38R light truck.
The mechanical solution adopted responded well to the requirements, with four-wheel drive and steering allowing a turning radius of 5 m (other sources claim 4.5 m).
In 1937, tests were conducted and, despite similar results to the model proposed by Breda, the FIAT prototype was chosen for presentation.
The FIAT-SPA prototype was presented to the Centro Studi della Motorizzazione (English: Motorization Studies Center) on 31st May 1938, and to the public on 11th July, during an army exercise in the Avezzano region. The official name, FIAT-SPA Trattore Leggero Modello 1937 (English: FIAT-SPA Light Prime Mover Model 1937), abbreviated FIAT-SPA T.L.37, was also chosen around this point.
In the course of 1938, 24 tractors were sent to Libya to test the towing of the Cannone da 75/27 Modello 1906 and also of ammunition trailers with a capacity of 100 rounds. These tests were judged very satisfactory, as the prime mover was able to solve the problem of the mobility of divisional artillery pieces in the loose sand of the desert.
The first Regio Esercito order for the T.L.37 was placed on 1st October 1937 for 250 units. The production capacity of FIAT-SPA increased from 39 units per month in the first half of 1939 to 135 units in the first half of 1940. In the first months of 1941, 150 T.L.37s were produced per month before dropping to only 100 units per month in late 1941. These numbers were insufficient to ensure both the replacement of losses and the horses that were towing artillery pieces in Italian artillery regiments.
The limited production numbers were not that bad. According to data, on 1st June 1940, only 467 75 mm and 100 mm artillery pieces from World War I had been modified to be towed by trucks and not just horses.
By 28th October 1940, 2,084 T.L. 37s had been ordered. By 1st March 1942, 1,021 vehicles had been delivered and 1,021 were in production. By 30th April 1943, a few days before the end of the North African Campaign, 2,267 FIAT-SPA T.L.37s were in service and 479 in production.
After the Italian Armistice with the Allied powers on 8th September 1943, almost all the FIAT-SPA T.L.37s were captured by the Germans, which also ordered the factories to continue production. Officine Viberti delivered 75 units in 1944 and 7 in January 1945.
The Repubblica Sociale Italiana (English: Italian Social Republic) also had a limited number of units in service, as did the Corpo Italiano di Liberazione (English: Italian Liberation Corps), the army that fought for the Allied forces in Southern Italy.
After the war, the T.L.37 remained in production in its T.37 version (similar to the A.S.37) until 1948 and remained in service into the 1950s, towing British 17-pdr cannons and 40 mm Bofors anti-aircraft autocannons.
Engine and Suspension
The FIAT-SPA T.L.37 prime mover was powered by a FIAT Tipo 18TL in-line four-cylinder gasoline engine that gave out 52 hp at 2,000 rpm. Its maximum revolutions per minute was limited to 2,000 rpm to increase its lifetime, reducing the need for maintenance and replacement.
The Zenith Modello 1936 TTHVI carburetor was designed for off-road and steep slope operations. The original Zenith air filter was replaced by a standard OCI oil bath model adopted by all T.L.37s sent to Libya. The engine-clutch assembly was suspended from the frame by four silent blocks. The gasoline tank placed in front of the cabin had a capacity of 100 liters and offered a range of 170 km.
The housing for the gearbox-differential unit was located in the center of the chassis. The housing had five gears plus a reverse gear. At the rear of the transmission box housing was the Power Take-Off (PTO) for the 2 tonnes winch. This meshed with the box’s output shaft when the vehicle was stationary. This mechanical complexity provided good performance to the vehicle but, at the same time, caused some parts to be fragile or to need constant maintenance by the crews.
For use in North Africa, three models of the FIAT-SPA T.L.37 were developed in 1941. The T.L.37 ‘Coloniale’ (English: Colonial) differed from the basic version by having Pirelli Tipo ‘Libia’ 11.25 x 24″ (22 x 60 cm) tires, a winch with more power, with a towing capacity of 2.5 tonnes, and oil-bath air filters for the engine.
The T.L.37 ‘Libia’ had, in addition to the same modifications as the ‘Coloniale’ Model, a muffler, an additional 150 liters tank mounted on the roof of the small rear ammunition rack, and two 35 liters removable tanks on either side of the chassis. These tripled the vehicle’s range to about 500 km.
The T.L.37 ‘Sahariano’ (English: Saharan), the third African variant, was identical to the ‘Libia’, but was equipped with Pirelli Tipo ‘Sigillo Verde’ tires.
The T.L.37 had a coil spring and torsion bar suspension on the front axle and the transverse leaf springs on the rear. All wheels were independent of each other for better off-road driving.
Structure
The FIAT-SPA T.L.37 light prime mover could carry, besides the driver, five gun crew on seats upholstered in black leather (replaced by black synthetic material from February 1942). It also had racks for the soldier’s personal weapons. The small ammunition rack at the rear could hold up to 290 kg of 75 mm or 100 mm ammunition. The folding waterproof canvas, which only partially protected the crew, was supported by two metal rods on each side, one folding on the rear shelf and one that could be folded behind the front seats.
The wheels, with 24″ (60 cm) full or perforated pressed sheet metal rims, could be equipped with Pirelli Tipo ‘Celerflex’ with a diameter of 1,098 mm. After 15th May 1939, the production vehicles were equipped with tires with inner tubes produced by the Pirelli company of Milan. These were the Pneumatici Tipo ‘Artiglio’ 9 x 24″ (22 x 60 cm) and Tipo ‘Artiglio a Sezione Maggiorata’ for continental terrain and Russian steppes, Tipo ‘Libia’ 11.25 x 24” (28.5 x 60.96 cm), Tipo ‘Libia Rinforzato’, Pirelli Tipo ‘Sigillo Verde’ 11.25 x 24″ for sandy soils, and Tipo ‘Raiflex’ for continental grounds. These were the same tires as used on the armored cars and camionette of the Regio Esercito.
In order to improve grip, the tires could be fitted with snow chains, while metal fins could be mounted to the wheels with semi-tires to help on ice.
The T.L.37 had a total weight of 3,560 kg with ‘Celerflex’ solid tires and 3,180 kg with the standard tires. Its payload capacity was 800 kg, while its towable capacity was 2.8 tonnes, enough to tow almost every type of artillery in the Italian ranks. The older Pavesi TL31 had a total weight of 2,950 kg, a payload of 500 kg, and a towable capacity of 2 tonnes.
From early 1942, a mount for a spare tire was installed on the rear of the structure. This modification was extended to already delivered vehicles. There were two towing variants depending on the type of artillery piece being serviced. For the Cannone da 75/27 Modello 06, the tow hook was about 200 mm longer.
The 6 volt electrical circuit was powered by a Magneti Marelli Modello D75R dynamo to power the two headlights, the tail light, the dashboard lighting and the Magneti Marelli T23 horn located under the hood, along with the steering system. As on many Italian military vehicles, the vehicle was also equipped with two acetylene headlights.
Main Armament
The Cannone Vickers-Terni da 75/27 Modello 1911 was an artillery piece used by the Regio Esercito during the First World War and Second World War. Its predominant use was as an artillery piece, although it was also occasionally used in the anti-tank role using specially designed projectiles.
Only five years after its adoption, the 75 mm Cannone da 75/27 Modello 1906 gun, developed by Krupp, was shown to have poor mobility during tests in Tripolitania in the 1912 Libyan War. The limited elevation of 7° to 16° was also criticized.
Moreover, the delivery delays accumulated by the manufacturers prompted the General Staff to reconsider the issue of horse-drawn field artillery. Thus, in 1911, after long comparative tests of the most modern Schneider, Krupp, and Deport pieces of German and French origin, the Italian Army decided to adopt the French 75 mm cannon. Although developed from a design by French Lieutenant Colonel Joseph-Albert Deport, the Cannone da 75/27 Modello 1911 was not a renewal of the French Army’s 1897 model, but a much more modern piece that served in the Italian Army as a training gun until 1950.
In 1915, after three years of production, the Regio Esercito had in service 125 batteries of the Cannone da 75/27 Modello 1911, i.e. 500 guns, assigned to the divisional artillery regiments and to the army corps. These 500 cannons were also supplemented by the cannons in depots and those assigned to the schools of instruction. The Cannone da 75/27 Modello 1911 was superior to the Škoda 8 cm Vz. 1905 and Vz. 1905/08 cannons in service with the Austro-Hungarian and German armies. Despite the losses suffered, especially during the retreat of Caporetto, the Royal Italian Army had a total of 820 Cannone da 75/27 Modello 1911s in September 1918.
The gun shield was produced with 4 mm thick armored plates. It could not be removed and also had the gunner seat bolted on it.
After the First World War, many studies were carried out to try to improve the performance of this gun and to try to amend the few weaknesses spotted during the war. The various projects were mainly aimed at increasing the range and improving the effectiveness of the ammunition used. The adoption of a new projectile in 1932 made it possible to increase the range from 10,200 meters to 12,000 meters and to double the explosive power of the projectiles used during the First World War.
The gun had a weight of 1,075 kg battery ready, with a maximum depression of -15° and a maximum elevation of +65°. It had a total traverse of 53° thanks to the modern trails.
The muzzle velocity was 502 m/s with standard High Explosive rounds and a bit more with the Armor Piercing rounds. The rate of fire could be up to 15 rounds per minute with a well trained crew, but it was usually maintained to 5 or 6 rounds per minute to avoid overheating the barrel.
Ammunition
The Cannone Vickers-Terni da 75/27 Modello 1911 could fire 75 x 185 mmR shells.
| Cannone Vickers-Terni da 75/27 Modello 1911 used during the Second World War ammunition | |||
|---|---|---|---|
| Name | Type | Note | Weight (kg) |
| Granata Ordinaria da 75 | High Explosive | 6.3 | |
| Granata Dironpente da 75 | High-Explosive (HE) | Twice more powerful than the World War I rounds | 5.2 |
| Scatola a Mitraglia | Canister | 238 16-mm lead spheres | // |
| Granata Perforante Esplodente | Armor Piercing High Explosive | // | |
| Granata Mod. 32 | Armor Piercing | 6.276 | |
| Granata Ordinaria Mod. 34/36 | High-Explosive | // | |
| Granata 1900/15N | High-Explosive | French rounds | // |
| Granata Mod. 17 | High-Explosive | French rounds | // |
| Effetto Pronto | High Explosive Anti-Tank | Entered in service in late 1941 and early 1942 in small numbers | // |
| Effetto Pronto Speciale | |||
| Effetto Pronto Speciale Modello 1942 | |||
| Proiettile a Grande Capacità | Smoke, incendiary, or toxic | Could be equipped with different charges | // |
Penetration was 50 mm of steel angled at 90° at 500 meters and 45 mm of steel at 1,000 meters with the standard Armor Piercing Granata Mod. 32 round making it capable of effectively countering British tanks in the early stages of the North African Campaign.
According to a test carried out in 1942, during a mission in Germany meant to test the effectiveness of the cannon against the Soviet T-34-76 tanks and transported to shooting ranges in Germany, the cannon could not seriously damage the vehicle. This was due to the low muzzle velocity.
Autocannone da 75/27 su FIAT-SPA T.L.37
The Autocannone da 75/27 su FIAT-SPA T.L.37 was a radical modification of the FIAT-SPA T.L.37 ‘Libia’. For that reason, it is sometimes also called Autocannone da 75/27 su FIAT-SPA T.L.37 ‘Libia’. The engine hood was the only part of the vehicle left intact, while the rest was completely changed to accommodate the 75 mm cannon. The steering wheel column was modified, lowering or angling it to permit the traverse of the main gun. Apart from the engine hood and the front cabin, the rest of the bodywork was cut out.
On the rear section was placed a small iron platform. On this platform, the gun trails were blocked in open firing position, along with two seats for the gun crew.
The driver and commander’s seats were left in place, but the 4 mm thick gun shield covered their field of view. On the right side, a small openable slot was cut to allow the driver to check the battlefield. On some other vehicles, the gun shield was cut more to allow the driver and the commander a better field of view of the front arc.
On the left side was a spare wheel. Due to the new combat role of the vehicle, it was more likely the tires would get hit by small arms fire. On the right side was a large ammunition rack, but the amount of ammunition is unknown. Under the platform, at the rear, a 150 liters tank was placed to keep the range at about 400 km.
The SPG had a crew of 6. The driver and commander were in the front, gunner and a loader on the rear of the vehicle, and other 2 gun crew were transported on another of the battery’s vehicles.
The gun traverse on the vehicle was 52°, 26° to each side. The depression was 0° because the gun cradle was leaning against the engine hood when at 0° elevation.
Operational Use
The Autocannone da 75/27 su FIAT-SPA T.L.37 was one of the last autocannoni produced by the Italian troops in North Africa. They were produced by the Autofficine del 12° Autoraggruppamento AS at the behest of the Comando Truppe Sahara Libico (English: Troop Command of the Libyan Sahara), the Libyan occupation force equivalent of the Guardia alla frontiera (English: Border guard) on the Italian mainland.
In March 1942, the first vehicles were ready and were tested, demonstrating decent mobility for a vehicle weighing nearly 5 tonnes and with an engine rated at only 52 hp. Thanks to the large tires, it had good flotation on the loose sand. For example, the Autocannone da 100/17 su Lancia 3Ro struggled in the same terrain.
The 12 Autocannoni da 75/27 su FIAT-SPA T.L.37 were assigned in groups of four to the 7ª Batteria, 8ª Batteria, and 9ª Batteria (English: 7th, 8th, and 9th Batteries) of the XVI Gruppo (English: 16th Group) of the Raggruppamento Celere Africa Settentrionale (English: North Africa Fast Grouping).
The Raggruppamento Celere Africa Settentrionale was composed of two gruppi celeri (English: fast groups), each composed of an armored car squadron with 24 AB40 and AB41 armored cars, one Gruppo Batterie da 65/17 Autoportate (English: Truck-mounted 65/17 Battery Group), one Gruppo Batterie da 75/27 Mod. 11 Autoportate, one Gruppo Batterie da 100/17 Autoportate, and one Batteria Antiaerea da 20/65 (English: 20 mm Anti-Aircraft Battery). These units were supported by 2 infantry battalions and a logistic unit.
The available literature is at times contradictory about the Raggruppamento Celere Africa Settentrionale’s history and organization. According to some, the total of 48 Autoblindo AB41 medium armored cars of the armored car squadrons had to come from the III Gruppo Esplorante corazzato ‘Cavalleggeri di Monferrato’ or GECo (English: 3rd Armored Reconnaissance Group). However, this unit was only sent to Africa in July with 18 armored cars and arrived in August 1942, under the command of Major Riccardo Martinengo Marquet. On the other hand, the Raggruppamento Celere AS was disbanded in May 1942.
Some sources then claim that the equipment used to fill the gap was an unknown number of armored cars from the III Gruppo Squadroni Corazzato ‘Nizza’ (English: 3rd Armored Squadron Group) that was formed in Turin in July 1941 and sent to Africa “during 1942”. It is plausible that the unit was equipped with a few armored cars from this unit or from others.
In the book ‘La meccanizzazione dell’Esercito fino al 1943’ written by Lucio Ceva and Andrea Curami, it is stated that 20 AB40 and AB41 armored cars arrived in Africa in February 1942 and another 63 in April of the same year. The same book reports that, in May 1942, there were a total of 93 armored cars in North Africa assigned to various units, among which was the III Gruppo Squadroni Corazzato ‘Nizza’ (40 armored cars in theory, 38 in service, serviceable and not), VIII Reggimento Bersaglieri Corazzato (also with 40 armored cars in theory, 31 in service, serviceable and not), the 3ª Compagnia della Polizia dell’Africa Italiana (10 armored cars assigned in theory), and the Raggruppamento Celere AS. Considering that, of 93 armored cars, 69 were assigned to the first two units, the remaining 24 armored cars were assigned to the 3ª Compagnia della Polizia dell’Africa Italiana and to the Raggruppamento Celere AS. This is less of the half of the 48 armored cars theoretically assigned to the Raggruppamento Celere AS alone.
When the Raggruppamento Celere Africa Settentrionale was disbanded in May 1942, the XVI Gruppo, equipped with the 12 Autocannoni da 75/27 su FIAT-SPA T.L.37, was assigned to the 136º Reggimento Artiglieria (English: 136th Artillery Regiment) of the 136ª Divisione Corazzata ‘Giovani Fascisti’ together with other autocannoni such as the Autocannoni da 65/18 su Morris CS8.
Here again, however, the sources mentioning this are in disagreement. Nico Sgarlato, in his book ‘I corazzati di circostanza italiani’, states that a total of 16 Autocannoni da 75/27 su FIAT-SPA T.L.37 SPGs may have been produced. If the source is correct, it can be assumed that the last four, most likely produced in mid-1942, were used to replace the losses of the XVI Gruppo, since no other batteries armed with such autocannoni were created. Other sources claim a total production of 20 or 30 units, but this seems to be an overestimation.
The ‘Giovani Fascisti’ artillery regiment was composed only of autocannoni batteries: the XIV Gruppo and XV Gruppo were equipped with Autocannoni da 65/17 su Morris CS8, the XVI Gruppo equipped with Autocannoni da 75/27 su FIAT-SPA T.L.37, the XVII Gruppo with Autocannoni da 100/17 su Lancia 3Ro, and, finally, the 88ª Batteria Artiglieria Contraerea (English: 88th Anti-Aircraft Artillery Battery) was equipped with Cannoni da 20/65 Mod. 1935 loaded on trucks.
This regiment, on paper, had a total of 48 autocannoni. Due to months of hard fighting against British troops, many had certainly been lost.
The last autocannoni were still used between 19th and 30th April 1943, during the First Battle of Enfidaville (now the Tunisian city of Enfidha) and in the Second Battle of Enfidaville. During these, the last forces of the 136ª Divisione Corazzata ‘Giovani Fascisti’ fought for an entire day, even after the declaration of the surrender of the Axis forces.
Conclusion
The Autocannoni da 75/27 su FIAT-SPA T.L.37 were the last desperate conversions done by the Regio Esercito’s workshops in North Africa. These clunky vehicles proved to be quite effective, albeit with limitations due to the total weight of the vehicle. Unfortunately, the very limited number of converted vehicles did not allow the design to have a large influence on the war.
They anyway supported the Italian troops during attacks and defenses during the North African Campaign awaiting some better designed and produced autocannoni to be entered in service.
Autocannone da 75/27 su FIAT-SPA T.L.37 specifications |
|
|---|---|
| Dimensions (L-W-H) | 4.13 x ~2 x 2.2 m |
| Total weight, battle-ready | 4.5 tonnes |
| Crew | 4 (driver, commander, gunner, and loader) |
| Propulsion | SPA Tipo 18TL petrol, 4-cylinders, 4,053 cm³, 52 hp at 2,000 rpm, 100 liter tank |
| Speed | 38 km/h |
| Range | 170 km |
| Armament | OneCannone Vickers-Terni da 75/27 Modello 1911 or Modello 1916 |
| Armor | // |
| Total production | 12 converted |
Sources
Italian Truck-Mounted Artillery in Action – Ralph Riccio and Nicola Pignato
http://www.regioesercito.it/reparti/cavalleria/regcav1.htm
Italian armoured and reconnaissance cars 1911-45 – Filippo Cappellano and Pier Paolo Battistelli
La meccanizzazione dell’Esercito fino al 1943 Tomo I Volume II – Lucio Ceva and Andrea Curami
I corazzati di circostanza italiani – Nico Sgarlato