Semovente da 47/32 su Scafo AB41

Kingdom of Italy (1942)
Armored Car – 1 Prototype Built

The Semovente da 47/32 su Scafo AB41 was a Second World War Italian heavily armed armored car prototype based on the AB41 medium armored reconnaissance car chassis.

The design for the Semovente da 47/32 su Scafo AB41 was presented to the Italian Regio Esercito (English: Royal Army) in late 1942, which subsequently requested a prototype. It was ready at the same time the North African Campaign was ending. The vehicle did not perform well during tests and it was abandoned in favor of the better armed and armored AB43 ‘Cannone’.

History of the ‘AB’ Armored Car Series Project

The ‘AB’ armored car series is the best known and most produced Italian armored car series of the Second World War. Its development started in the late 1930s, after the experiences of the Spanish Civil War showed to the Royal Italian Army High Command that the currently-used armored cars, like the Lancia 1ZM, were unsuited to modern wars. At roughly the same time, the police force that dealt with public order in the Italian colonies, the Polizia dell’Africa Italiana (PAI) (English: Italian African Police), issued a request for a new armored car to equip its reconnaissance units, especially for anti-guerrilla roles.

FIAT and Ansaldo started a joint project to develop two armored cars with the maximum communality of parts based on the SPA TM40 (TM for Trattore Medio – Medium Tractor). These were later unified and presented alongside the FIAT 626 medium and FIAT 666N heavy duty truck prototypes to Benito Mussolini, dictator of the Kingdom of Italy at the inauguration of the new FIAT Mirafiori plant in Turin on 15th May 1939.

After some modifications, production started in January of 1941. By the end of the war, a total of about 800 armored cars were produced: 24 AB40s, 667 AB41s,102 AB43s, and a dozen prototypes of various vehicles such as, command armored cars, anti-tank armored cars and lightweight armored cars.

History of the Semovente da 47/32 su Scafo AB41 Prototype

As the North African campaign progressed, British reconnaissance vehicles were outfitted with thicker armor and more powerful guns. In 1940, British armored cars were appearing on the battlefield armed with heavy machine guns chambered for cartridges ranging from 13.5 mm to 15 mm. By 1942, the British started fielding armored cars armed with 40 mm guns and with heavier armor, from 7 mm to 12 mm of the Morris CS9 or the Rolls-Royce armoured car to 16 mm to over 20 mm of the Marmon-Herrington and Daimler armoured cars. The same year, the Ispettorato Truppe Motorizzate e Corazzate (English: Motorized and Armored Troop Inspectorate) requested Ansaldo to develop a new armored car with a more powerful armament to deal with these British reconnaissance vehicles.

Ansaldo started the development in June of 1942 and, in December of that year, finished assembling the prototype with license plate ‘Regio Esercito 665B’. Testing of the Semovente da 47/32 su Scafo AB41 (English: Self-propelled gun armed with 47/32 on AB41 chassis) started in early 1943.

Design

Hull

The armor on the hull and superstructure consisted of all bolted plates, which did not offer the same protection as welded plates, but simplified the replacement of armor plates for repairs. The front and rear of the hull was 8 mm thick, while the sides were 8.5 mm thick.

The original turret and roof of the AB41 were removed and replaced with vertical walls to create an open-topped vehicle. A 10 mm thick armored shield was placed at the front of the open-topped section where the main gun was to be mounted to protect the gunner from enemy fire. The fenders were also armored to prevent enemy fire from damaging the tires.

The hull of the armored car had an internal structure on which the plates were bolted. At the rear of the superstructure were the two armored access doors for the crew compartment, divided into two parts, which could be opened separately. The radio antenna originally on the left of the superstructures was removed from on the Semovente da 47/32 su Scafo AB41, since no radio was mounted. Had the Semovente da 47/32 su Scafo AB41 gone into production, a radio may have been included.

A horn was mounted on the right side of the front of the hull and a pickaxe was stored on the right side of the hull. The exhaust pipe sat on the rear fender and two spare wheels were placed in fairings on the sides of the superstructure.

Above the engine compartment, there were two air intakes and two hatches for engine maintenance. The back was left unchanged from the original AB41 hull, with the cooling grilles, inspection hatches and rear lights.

Engine and Suspension

The Fabbrica Italiana Automobili di Torino, more commonly known as FIAT (English: Italian Automobiles Factory of Turin), and its subsidiary, Società Piemontese Automobili (SPA) (English: Piedmontese Automobile Company), designed a new engine by upgrading the original engine of the AB41, the FIAT-SPA ABM 2 6-cylinder petrol water-cooled engine, with a 4,995 cm³ displacement. This engine developed a maximum power of 88 hp at 2,700 rpm and was itself derived from the FIAT-SPA ABM 1 mounted on the AB40, which had less displacement and a maximum power of 78 hp.

The Semovente da 47/32 su Scafo AB41‘s new engine was the same as on the Autoblinda AB42 and the future AB43, the FIAT SPA ABM 3. The displacement remained unchanged, 4,995 cm³ as the previous models, but the maximum power was increased to 108 hp (sources alternatively list this figure as 100 hp, 110 hp, and 115 hp) at 2,800 rpm. This significantly increased the speed on roads to about 90 km/h, compared to 80 km/h of the AB41 and 78 km/h of the AB40.

On this armored car version, as on the AB42, the dual-drive system and rear controls were meant to be removed. The chassis was not meant to be that of the AB40 or AB41, but that of the AB42, and the same used on the SPA-Viberti AS42 ‘Sahariana’. For this reason, some sources claim that this armored car was named Semovente da 47/32 su Scafo AB42 or Autoblinda AB42 con 47/32. However, this was not the case for the prototype

The modifications were made to lighten the chassis, which maintained the 4×4 configuration, but only the frontal wheels steered. The suspension for each wheel was independent, with a coil spring for each wheel.

The photos of the interior of the vehicle show some mechanisms for reverse driving, such as the dashboard for the rear driver and the directional control lever which, when lowered, allowed the rear driver to take control of the vehicle.

This means that, in order to save time and resources, the prototype was probably built on the chassis of an AB41 that was partly modified.

The production vehicles would have been produced on the AB42 chassis. There were three fuel tanks totaling 195 liters. The 118-liter primary fuel tank was in the double bottom of the floor which made it vulnerable to anti-tank mine explosions. The 57-liter secondary tank was mounted in front of the driver, above the steering wheel, while the 20-liter reserve tank was placed in the rear, where on the AB40 and AB41 was placed the rear machine gun. On the left of the reserve tank was a 10 liter water tank used for engine cooling.

As on the AB40 and AB41, there was a serious problem with the lack of a bulkhead between the crew compartment and the engine compartment. The presence of the 20 liters reserve tank in front of the engine was also an issue as, in case of fire in the engine compartment, the lack of bulkhead would cause the propagation of the flames inside the crew compartment.

The Semovente da 47/32 su Scafo AB41 probably had an unchanged range of 400 km. The prototype was fitted with the tires developed by Pirelli specifically for desert terrain, the Pirelli Tipo ‘Libia’ 9.75 x 24″ (25 x 60 cm). Unsurprising, the rims were not modified and the vehicle could have mounted all the tires produced by Pirelli for the 24″ rims, also used on the other AB series armored cars, the Camionette SPA-Viberti AS42, AS43, and for the SPA TM40 prime mover.

Armament

The main armament on the Semovente da 47/32 su Scafo AB41 was the Cannone da 47/32 Modello 1935, nicknamed ‘Elefantino’ (English: Little Elephant) by the soldiers. This gun was designed by the Austrian Böhler company and over 3,200 units were produced under license by various Italian companies for the Regio Esercito from 1937 to 1945. The main producers were Società Italiana Ernesto Breda per Costruzioni Meccaniche of Brescia, Arsenale Regio Esercito di Torino (ARET) (English: Royal Army Arsenal of Turin), Arsenale Regio Esercito di Piacenza (AREP), and Ansaldo-Fossati in Sestri Ponente. Designed as an infantry support cannon, it proved to be reliable and precise during the Spanish Civil War and the Ethiopian War. With its armor piercing rounds, it was well able to take out the few opposing armored vehicles it could expect to find in North Africa. Its maximum range was 7,000 m, but it was effective up to 4,000 m for infantry support and about 1,000 m for anti-tank fire.

The gun was mounted on a rectangular structure running horizontally between the superstructure’s sides. It had a traverse of about 40° on the left and right, with a vertical elevation from around -4° or -5° to not more than +20°.

Ammunition

The cannon had a rate of fire of 28 rounds per minute for the field artillery piece and of about 20 rounds per minute on the wheeled tank destroyer due to the cramped space. The ammunition total consisted of 100 rounds in two rectangular metal racks, each welded under the rectangular structure where the gun was placed.

The cannon fired 47 x 227 mm R rounds of five different types:

Cannone da 47/32 ammunitions
Name	Type	Fuze	Projectile weight (kg)	Muzzle Velocity (m/s)
Cartoccio Granata Dirompente da 47 modello 1935	High-Explosive	Percussion Mod. 35 or Mod. 39	2.45	250
Cartoccio Granata Perforante da 47 modello 1935	Armor Piercing – Tracer	Percussion Mod. 09	1.42	630
Proietto Perforante Modello 1939	Armor-Piercing Composite Rigid – Tracer	Percussion Mod. 09	1.44	650
Proietto Controcarri Effetto Pronto	High-Explosive Anti-Tank	Internal Mod. 41	1.2	//
Proietto Controcarri Effetto Pronto Speciale	High-Explosive Anti-Tank	IPEM front fuze	1.5	//

Precise values on the penetration of the Mod. 35 armor-piercing ammunition are not available. However, an Italian document of the Spanish Civil War era states that it could penetrate 37 mm of armor at a distance of 700 m. The Mod. 39 armor piercing ammunition could penetrate plates with thicknesses of 55 mm at 100 m, 40 mm at 500 m, and 30 mm at 1,000 m, angled at 0°. The HEAT ammunition was rarely used due to its late production in the war and infrequent distribution to the crews. There is also no precise data on the penetration of the HEAT ammunition of the 47 mm gun, but an Italian report from some tests in October 1942 shows that the Effetto Pronto round was not able to penetrate the 52 mm thick side armor of the turret of a T-34/76 Mod. 1942 captured by the Italians on the Eastern Front. The Effetto Pronto Speciale round, produced in very few numbers between early 1943 and the end of the war, had greater anti-tank capabilities and was able to penetrate the front armor of an M4 Sherman.

Crew

The vehicle had a crew of three with the driver in the front of the hull, the gunner/commander seated on a seat under the gun breech, and the loader standing by the gunner. In addition to directing the crew, the commander also operated the main gun and observed the battlefield. The driver would have had a lot of trouble getting in and out of the vehicle as he had to squeeze through the narrow gap between the ammunition stowage racks, the gun’s trunnions, and the commander’s seat to enter or exit his compartment.

Testing

The Semovente da 47/32 su Scafo AB41 was finished on 3rd December 1942 and was taken to the Centro Studi della Motorizzazione (CSM) (Eng: Centre for Motorisation Studies) for testing vehicles and determining whether they should be adopted or rejected by the army.

The results were not good. The height of the gun shield, superstructure walls and cannon raised the center of gravity of the vehicle, making it unstable and increasing the risk of rollovers. The height of the vehicle caused other problems. In the flat deserts of North Africa, a vehicle of this height would have been quickly detected by British anti-tank units. However, the tests demonstrated the effectiveness of the main gun. The 47 mm cannon would have offered excellent firepower to the Italian scouting units.

The biggest problem, as would also happen with the AB42, was that the prototype was ready for testing only after the Italian defeat against Commonwealth troops at the Battle of El Alamein that lasted from 23rd October 1942 to 5th November 1942. This battle put the Italian and German troops on the backfoot in North Africa. Above all, it showed the High Command of the Royal Italian Army that the North African Campaign was lost and that it was a poor use of resources to invest money into vehicles specially developed for desert use.

Subsequent Developments

When the project was not accepted by the Centro Studi della Motorizzazione, Ansaldo and FIAT started a new project that would become the Autoblinda Modello 1941 con Cannone da 47/40 Modello 1938, more simply known as AB43 ‘Cannone’. The prototype was presented to the High Command of the Royal Army on 21st May 1943 and satisfied the requests of the Ispettorato Truppe Motorizzate e Corazzate. The Regio Esercito ordered 380 AB43s and AB43 ‘Cannone’s in summer 1943, but the Armistice signed on 8th September 1943 stopped the production of the armored car.

Conclusion

The Semovente da 47/32 su Scafo AB41 was a failed project of Ansaldo, which wanted to produce a vehicle that could meet the requests of the Royal Italian Army and, at the same time, that did not require an expensive modification of the assembly lines.

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Semovente da 47/32 su Scafo AB41 Specification
Dimensions (L-W-H)	5.20 x 1.92 x ~2.5 m
Total Weight, Battle Ready	~ 7 tonnes
Crew	3 (driver, loader, and commander/gunner)
Propulsion	FIAT-SPA ABM 3, 6-cylinders 110 hp engine with 195 liters tanks
Speed	Road Speed: 80 km/h Off-Road Speed: 50 km/h
Range	400 km
Armament	One Cannone da 47/32 Modello 1935 gun with 100 rounds
Armor	8 mm to 10 mm
Total Production	1 prototype

Sources

Gli Autoveicoli da Combattimento dell’Esercito Italiano, Volume Secondo, Tomo I – Nicola Pignato and Filippo Cappellano