M.10 «TANK DESTROYER»

The first campaigns of WWII had clearly showed the superiority of the automotive anti-tank guns over the towed artillery and more, over the horse-drawn one.

In the first place, the American army adopted the 37 mm gun mounted upon WC-51 Dodge and the 75 mm gun upon M3-type half-track armoured chassis. But neither the first nor the second one could be considered as real fighters for automotive tanks. It was only with the performance of the M.10 3”Gun Motor Carriage that the American army was actually in hold of such material.

The M.10 was the first tank-fighter with a rotary turret. In order to reduce down to a minimum delay the implementation of the M.10, the mechanic, the engine and the rolling parts of the Sherman M.4A2 were adopted. Only the chassis and the turret were of a brand new design, with a predominance of oblique surfaces. This represented a clear progress in comparison with the tanks of that time with vertical armouring plates, which had real “shell traps”. The upper part of the chassis more particularly was made of very tilted plates and, like the turret, were having bolts enabling the fixing of additional armouring plates that could incidentally be used as a combat tank.

Launched in the Grand Blanc arsenal in September, 1942 and reinforced by the assembly lines of the Fisher Tank Division, production reached 4,993 units at the end of 1943.

The maximum armouring thickness was only 37 mm, but the side and rear plates were strongly tilted for a better protection, unlike the genuine chassis.

The M.10 got the General Motors Diesel engine of the M.4 A2 and the following version M.10A1 (exteriorly identical) the 8 cylinder GAA Ford engine of the M4 A3.

The crew was of five men.

The engine had a very good mobility, thanks to its transmission and to its 5 gear box plus the reverse gear.

The miscellaneous variants had a main difference between them by the type of their turret’s counter-balance. The first units engaged in North Africa didn’t have any at all. The next series received two very characteristic rectangular plates. The second version, more widely spread, presented a counter-balance of a rather complex shape, which, when looked at from the side, appeared as the prolongation of the inferior plate of the rear of the turret.

After WWII, the TD10 DESTROYER was progressively withdrawn from the active duty as from 1950.

M.24 «CHAFFEE»

Once the M.5 A1 light combat tank evidenced as being insufficient, above all with respect with its armament, the Americans started to work with a view to designing a new armoured vehicle of the 18-ton class.

A prototype was soon carried out, from the excellent T.7 tank, manufactured in various forms by the Rock Island arsenal. The Brits showed interest as well, them wishing it to be armed with a 57 mm gun, while the Americans preferred a 75 mm gun. But the importance of the modifications sought, the increase of the armouring in particular, had the T.7 tank transformed into a medium/light tank, which turned out to be inefficient in both categories.

It was then decided to start reviewing the problem from the very ground level, and, on April, 1943, Cadillac, who already were manufacturing the M.5 A1 Stuart VI, undertook a project aiming at suppressing every defectiveness noticed on this latter : too narrow a turret, insufficiency of cooling, and armouring too narrowly calculated in relation with its mass.

The theoretical survey came to termination on October, 1943, with the definition of a prototype called M.24 whose services appeared so attractive that a first authorisation of order was given for 1,000 units, abreast with the agreement on the development of a new version : the T.24E1, which remained with the use of the M18 tank hunter’s mechanic, but armed with a longer gun. The ending of the hostilities put an end to the experiments conducted in that direction.

The assembly lines of the Cadillac manufactures in Detroit, Mi. were arranged for the production of the new standardized tank under the denomination of Light Tank M.24. The first unit of mass production could be delivered in April, 1944. In Milwaukee as well, Massey-Harris got ready to produce 1,000 other M.24s, and already several by-products were under survey. The program provisioned the manufacturing of 5,000 chassis. The manufacturing of the 105 mm auto-motor upon a m.24 chassis was to be entrusted to the American Car and Foundry, but after October 1945, the order was transferred to Cadillac, whose part of production was already terminated.

The M.24, which was one of the best combat tanks ever manufactured, had a classic shape : rear engine and transmission, armament in the centre and sprocket wheel reduction gear up front. A firewall was separating the engine compartment from the crew one. The pilot was at the left of the turret, with his assistant who acted also as a radio operator, on his right.

The suspension was made of torque strut and hydraulic shock-absorbers, like the M.18 chasseur. The M.24 was a very stable shooting platform. The rolling set had five rubber running wheels and four support rollers for each track. The steel reversing pulley, located at the rear, was mobile in order to allow the regulation of the track’s tension. This latter could be of two types : made of steel or equipped with rubber supports

The case had a low and well profiled shape. It was made of steel plates that were electrically welded and whose tilting had been carefully surveyed. The M.24 had two 3g Cadillac independent engines, located at the rear part of the case. They were of the V8 type, with a classic carburettor and water cooling system. The transmission had two hydraulic coupling gears, one per engine, two epicyclic gear boxes with automatic hydraulic control by a centrifugal controller that acts upon the transmission.

In June, 1945, the total M.24 tanks produced amounted 4,070 units.

The first corps to be equipped with it among the Allies was in 1945 the British Tank Corps, which re-named it Chaffee MK.1 (after the name of Gen. Adna R. Chaffee, the father of the armoured weapon in the U.S.).

After the war, the M.24 had a decisive part in Corea. At the same moment, the French M.24 Tanks were fiercely fighting in Indochina, more particularly in DIEN BIEN PHU where a platoon was sent airborne.

The M.24 was taken over progressively by the M.41 light tank and the AMX 13 as from 1950.

THE M.4 «SHERMAN»

At the end of the surveys concerning the medium M.3 tank program, on March, 1941, the technical services of the American Army immediately focused on the surveys concerning its successor, the M.4. The goal was to design a rotary turret on 360° for a 75 mm M.3. gun, with the indispensable modifications in the chassis but no alteration to occur neither on the mechanic nor on the engine’s propelling and rolling elements

The new tank’s prototype, named T.6, was of the cast solid moulded type. Later, to simplify the manufacturing, the chassis of several series were assembled by welding.

The engine was sent to the Aberdeen polygon of tests on September, 1941. Its production in large series received the highest priority and the M.4 substituted itself directly to the M.3. upon the assembly chains, without any solution of continuity.

This new combat tank’s selection met the British need for a powerful armoured engine that was in a position to re-establish the balance on the African territory, and as well with the American re-armament. From the fore-project to the first deliveries, only 13 months passed. The M.4. is to be considered as one of the most beautiful industrial successes of all times. Its manufacturing continued until April, 1945. When the last one left the Detroit assembly chains, 48,071 tanks had been delivered, which belonged to thirty or so versions more or less different. The first ones arrived in the middle of year 1942. The Brits called this tank SHERMAN, after the Northerner General from the Secession War.

The Sherman is by all means the most famous allied combat tank of WWII.

The manufacturing of the M.4 tank was entrusted to several simultaneous builders and the various series were above all different from their engines.

The basic M.4 version was authorized on October, 1941.It has aiming slits in the tilted frontal armour-plate, a three-side protection for the differential, a welded chassis and a 75 mm gun under the M.34 configuration. On some of the first models, some sustaining runners remained to be found, located on the cars’median axis, like on the M.3. The engine was a star-shaped 9 cylinder R.975 Continental engine.

The M.4A1 variation was selected two months later, with a chassis manufactured by moulding and rounded surfaces in order to have the projectiles bounce. The alterations that were brought during assembly were the same than the M.4., plus the protection of the differential that was on one piece now. Besides, the first examples of reinforcement of lateral armouring with addition of rectangular plates welded upon the chassis, were noted.

At the same time, on December, 1941, the M.4A2 showed up. Very akin to the M.4, it was moved by two gas-oil G 6-71 General Motors.

The M4A3 was looking like the M.4 as well, but it had a 500 HP Ford engine with 8 V-shaped cylinders cooled by liquid, which had been specially designed for this tank.

The M.4A4 version appeared on February, 1942. It was destined to the British Army and always alike the M.4, but with a 30 cylinders Chrysler Multi-bank 5 engine, which needed a slight prolongation of the chassis (33 cms)

The version that was built in Canada was called M4.A5/ The M.4 A6 version kept the M.4.A4 prolonged chassis to locate a RD-1820 Ordnance engine with air-cooling. It was built only in 75 units from October 1943 to February, 1944.

The M4.A3E variation, deemed “Assault Tank”, knew a better destiny. 254 units of it were delivered from March to June, 1944 It was a Sherman with a reinforced chassis and frontal section, until reaching a 100 mm armouring, and 152 mm for the turret.

The Sherman basic armament was the 75 mm gun.

Later there was a series of M.4 which were armed with a 105 mm howitzer.

From the impressive range of the different versions of the Sherman tank, only the M.4A1, M.4A3 and M.51 Super Sherman pursued a long career in the allied armies. Nonetheless, even those version were progressively withdrawn from the active duty between the ‘60s and ‘80s due to their being obsolete.

THE SEXTON

As it turned out necessary to have an ever-growing mass of combat tanks, the authorities of the British Industry of war sought the industrial possibilities of the former colonies to the benefit of the common effort of war. Canada undertook a patented production of combat tanks, further to some modifications. They started the survey of an adapted version of the M3 American tank which lead to the designing of a cast steel case like the one of the Sherman tank still under survey.

With its manufacturing starting on 1941, this new model represented a synthesis of all the most recent progress that had intervened into the evolution of the armoured vehicles in Great Britain as well as in Canada. The Ram was armed with a 40 mm gun in turret, plus a machine-gun that was mounted on a smaller turret besides the pilot.

The most important by-product of the Ram was the Sexton, a 88/27 auto-motor carried out upon the model of the American M7 Priest, to meet a specification from the British staff on September 1942. Its survey, which started on March 16th, 1942, provisioned for the use of the Ram II’s chassis, modification as minor as possible to the 88 field gun (the “25 pounds”), the maintaining of the genuine aiming equipment and as strong as possible an allocation of board ammunition.

The prototype, which was completed on August 28th, was shipped to Great Britain on November 5th. Upon termination of the usual testing, the Sexton, deemed “the best vehicle of this class”, received its probation, which was immediately followed by an order for 84 units. An actual 1836 were manufactured plus 124 for Canada and 180 for China.

The 124 first units, called “Sexton I”, had neither battery nor auxiliary generator. All the following ones were named “Sexton II” and a little at a time were granted with numerous improvements. Some unarmed variants were arranged as batteries centrals. The majority of the Sexton was engaged by the British and Canadian forces into the last battles of the war.

They were later massively withdrawn from the active duty during the year sixties, because of their technological obsolescence.

M8 «GREYHOUND»

The creation of the armoured weapon in the United States goes back to July, 1940. It absorbed the means of the infantry and the cavalry, and became the heir of the interest that was traditionally showed toward the armoured engine on wheels. In the scope of the modernization of the American land forces, several thousands engines of the kind were planned in line.

Following the agreements signed on March, 1941 with the Brits, agreements with a view to furnishing an American material of war adapted to an Euro-African operating field, the direction of Artillery spread a specification for a medium 4WD armoured engine armed with a 37 mm gun. The propositions submitted by two manufacturers were deemed interesting, i.e. the one from Ford (the T17 6 x 6 model) and the one from Chevrolet (T17E1, 4 x 4). The tests took place until October, 1942, and the decision was made to concentrate the production upon the sole T17E1, limiting to 250 units the manufacturing of the T17 to enable the manufacturer to make the junction with the M.8 assembly line. This latter’s origin was a request from the tanks’fighters command concerning a vehicle that could give the 37 mm gun a maximum mobility. After the manufacturing, many prototypes, this specification gave birth to a model of light armoured engine, the T22, which was adopted on May, 19, 1942 under the denomination of M.8.

Finally, in order to meet the necessity to have a vehicle that was able to receive various combinations of armament, the manufacturing of a version of the M.8 without a turret was decided, which was named the M.20.

This way, in 1943 the American industry has been in a position to provide four models of armoured engines :

The T17 (baptised Deerhound) allocated to the Military Police ;

The T17E1 (Staghound) – almost entirely destined to the British forces ;

The M.8 which production continued until 1945 and reached 11,667 units for the American Army (this was one of the most spread armoured engines),

And its derivative, the M.20.

A certain amount of M8 and M20 (which official name was Armoured Utility Car) was identical on a mechanical viewpoint. It was welded and propelled by one sole Hercules JXD engine fixed on the rear part. The transmission was a 6 x 6 classical type, with a gear box showing 8 forward and 2 backward ratios. The pilot and the co-pilot were sitting up front in a compartment that was slightly elevated. During security movements, they could tilt towards the exterior and forward the four armour-plates that formed the compartment’s roof. During action, the visibility was ensured thought protected slits. On the rear part, the chassis had a towing hook. The wheels’lateral protection was ensured by removable anti-sands.

Under the M.8 version, the car was mounted by a trunk turret, in the open air, which shielded a 37 mm light gun.

The M.8 and M.20 version were withdrawn from the active duty as from the ‘60s.

THE WHITE M3A1 SCOUT CAR

The White M3A1 Scout Car had a fairly short operational career amidst the US Army. Designed around 1930, it already lagged one generation behind the modernism of the Jeep and of the Half-Track, while nonetheless being used as a basis of survey.

Built by the White Automotive Company as from 1938, its limited capacities had it deemed as from this very period as an obsolete combat vehicle, all the more so after the North-African landing.

Initially, the White Scout Car was to be used for the operations of all-terrain and off-roads reconnaissance of the armoured units.

Nevertheless, its meagre capacities off-roads and the problems linked to its suspension derived from a civil truck had it more agile on roads.

Moreover, its 110 HP Hercules engine was slightly lacking power to move its 5.6 tons weight. The Scout Car was also suffering from an extra overall dimension and from a bolted vertical armour-plating that was not sufficient and that had it less discreet than the Jeep and less protective for its occupants than the Half Track.

A metal roller mounted on the shock absorber and fixed at the vehicle’s front part was in assistance when jumping over ditches. A sturdy steel-plate bumper upon which two towing-hooks were fixed was completing this device. Four armoured throttles protected the radiator, they could be either opened or closed by the passenger up front by a control lever at his feet. A folding protection device that was made of a steel armouring plate, equipped with sliding vision hatches could reinforce the front armoured windscreen. The upper part of the side doors was mounted upon hinges and could be folded at will. It was also equipped with a sliding vision hatches system. The rear part of the vehicle had no access door so the crew turned out to be vulnerable to the enemy shots in case of an emergency evacuation.