The AMX 40 was a proposed French

cruiser tank The cruiser tank (sometimes called cavalry tank or fast tank) was a British tank concept of the interwar period for tanks designed as modernised armoured and mechanised cavalry, as distinguished from infantry tanks. Cruiser tanks were develop ...

. It was intended to replace the

SOMUA S35 The SOMUA S35 was a French cavalry tank of the Second World War. Built from 1936 until 1940 to equip the armoured divisions of the Cavalry, it was for its time a relatively agile medium-weight tank, superior in armour and armament to its French ...

and S40 tanks. The tank never went beyond design stage after the

Fall of France The Battle of France (french: bataille de France) (10 May – 25 June 1940), also known as the Western Campaign ('), the French Campaign (german: Frankreichfeldzug, ) and the Fall of France, was the German invasion of France during the Second World ...

Development history

In April 1939, a French military mission led by General Martin visited the British military. They were impressed by the British

Cruiser Mk III The Tank, Cruiser, Mk III, also known by its General Staff specification number A13 Mark I, was a British cruiser tank of the Second World War. It was the first British cruiser tank to use the Christie suspension system, which gave higher speeds ...

and decided to make an improved cavalry tank based on it which would later be known as AMX 40.Stéphane Ferrard,''GBM n°95'', 2011, pg 78-86 After the start of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

, development of the AMX 40 commenced in March 1940 under the leadership of Joseph Molinié from

Ateliers de construction d'Issy-les-Moulineaux {{unreferenced, date=May 2017 The Ateliers de construction d'Issy-les-Moulineaux (English translation: construction workshops of Issy-les-Moulineaux) were born from the nationalization of the Renault factories in Issy-les-Moulineaux in 1936. They w ...

. The AMX 40 was a

, planned to be a successor to the

and

SOMUA S40 The Somua S40 was a prototype French tank developed before Second World War. It was based on the Somua S35. Compared with the latter, the S40 had a new diesel; its hull was longer than the S35; and an extra pair of wheels was added on the suspens ...

. However, in July 1940, the design was discontinued after the

Design

The AMX 40 was ahead of its time in some aspects; the hull and turret were well sloped and had no straight angles. The tank was manned by a crew of 3.

Hull and turret

The AMX 40 was designed to be approximately 33 cm wider than the S35 while maintaining approximately the same length, which improved its handling. Construction was entirely cast. The frontal armor had a nominal thickness of 60mm, although surviving drawings suggest that the heavily sloped upper glacis was somewhat thinner. The side armor ranged from 30mm to 50mm and the rear armor was 40mm. The two-man egg-shaped turret had two openings for the optical

rangefinder A rangefinder (also rangefinding telemeter, depending on the context) is a device used to measure distances to remote objects. Originally optical devices used in surveying, they soon found applications in other fields, such as photography an ...

. The turret ring diameter was of only 90 cm. There was a circular access hatch of 60 cm in diameter at the rear of the turret. There were no vision slits for the turret of the AMX 40.

Armament

The planned main armament was a 47 mm SA35 gun. 176 rounds were stowed in the fighting compartment in rotary and tilting magazines in order to be reached quickly. Secondary armament included two 7.5mm machine guns; one coaxial machine gun and one

anti-aircraft defence Anti-aircraft warfare, counter-air or air defence forces is the battlespace response to aerial warfare, defined by NATO as "all measures designed to nullify or reduce the effectiveness of hostile air action".AAP-6 It includes surface based, ...

machine gun mounted on a retractable ball mount behind the turret. Up to 30 magazines were stored in a large belt mechanism to the right of the driver. It was believed that this system would allow the loader to continuously grab magazines without needing to crawl around inside the hull.

Engine

The AMX 40 was supposed to use a two-stroke Aster

diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...

similar to the one used on the

AMX 38 The AMX 38 was a prototype French tank designed in 1937 at the AMX works. Designed as AMX's response to the 20-tonne tank programme intended to replace the aging Char D2, it was a faster and heavier alternative to Renault R35, in practice a cros ...

. The choice of diesel fuel significantly increased safety by preventing ignition at room temperature. The engine horsepower was noticeably less than the SOMUA S35 () and SOMUA S40 (), despite the fact that the tank's weight was close to the SOMUA S35. A , six-cylinder version of the Aster engine was under development

Running gear

The chassis had eight road wheels of 82 cm diameter, on a horizontally-sprung

Christie suspension The Christie suspension is a suspension system developed by American engineer J. Walter Christie for his tank designs. It allowed considerably longer movement than conventional leaf spring systems then in common use, which allowed his tanks to h ...

. There were no return rollers. The road wheels were protected by 15 mm steel side skirts. Like many tanks fitted with Christie suspensions, the AMX 40 was a "convertible tank"; in the event of a broken track, the crew could remove the tracks and use the two

rear-wheel drive Rear-wheel drive (RWD) is a form of engine and transmission layout used in motor vehicles, in which the engine drives the rear wheels only. Until the late 20th century, rear-wheel drive was the most common configuration for cars. Most rear-wheel ...

s, allowing the tank to travel at high speeds on roads. In wheeled mode, the tank was steered by pivoting the two front road wheels.

Communications, optics, and crew

The AMX 40 was to be equipped with a

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...

. Vision was achieved by a panoramic

periscope A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position. In its simplest form, it consists of an outer case with ...

located on the top of the turret.

References

External links

AMX 40 at Tank Encyclopedia
{{WWIIFrenchAFVs World War II tanks of France Medium tanks of France