I visited the French archives once again, a bit less content found this time. It was about the organisation and equipment of French armored forces between 1919 and 1924, as in what they intended to do in the long run.
The French were envisionning the following types of tanks
- a light tank armed with machineguns (or a machinegun and a 20mm gun/autocannon or a 37mm gun) around 8-11 tons with a 90hp engine and greater mobility (10kph minimum on tracks), armor against expected infantry weapons (20mm in the front). Basically meant to fight forward, of minimum size and weight to be fielded in large numbers and be easily transportable and use light pontoons.
- two types of support tanks armed with a short 75mm gun. One with good protection and firing directly at targets and in particular tanks, the other was a sort of open top SPG firing indirectly from a safe position.
- a recon tank with minimal armament but greater speed (20kph minimum) and/or protection to be able to move ahead of other formations and probe enemy defenses. Equipped with a radio.
- support tracked vehicles: an APC, a fuel/ammo carrier, a radio tank, a carrier tank or bridgelayer to cross obstacles.
- eventually a heavy breakthrough tank on the lines of the FCM 2C.
One can imagine that the use of tracked carriers for 105, 155 and 194mm guns as seen in late WW1 would continue.
Overall the French system was rather logical and complete for the early 20s, but the lack of funding meant that obviously none of the replacement and special vehicles mentionned saw the light of day in the expected timeframe (by 1925-26). It is only in the early 30s that the B1 and D1 series matured enough to somewhat fill the expected roles of 75mm direct fire tank and light tank imagined since 1920 respectively.
I have learnt about a few specific developments however. One from 1922 or so was a proposed upgrade of the Renault FT as a stopgap until a new tank is fielded in 1926, to remain relevant against the potential proliferation of the German MG 18 TuF heavy machinegun. The core idea was to increase the armor thickness by 10mm in places (so about 26mm at the front and 18mm on the sides if done), adding 700kg. This increase in weight would be compensated by an interesting development of the time: a new cooling and fuel delivery system. The existing cooling system (radiator + fan) was problematic because fan belts broke regularly. A solution by the Bloch-Sautter-Harlé company was what we call an ejector type cooling system, where the energy required to suck the air in and out of the tank is provided by the exhaust gases going through a nozzle. This system would be successfully used in some Soviet vehicles much later, but it was hoped for the FT that it would save an additional 7hp and greatly reduce maintenance requirements.
The other developments were from much later in 1929 or so. There was an idea to modernize the FCM 2C heavy tank by replacing the existing German 2*175hp engines by 2*250hp and increase armor thickness to 45mm everywhere instead of just the front. Additionally, it appears that the French were working on a new model of FT BS casemate (the FT BS was a casemated variant of FT with a short 75mm howitzer), as well as Junkers and Peugeot diesel engines for some unknown tank.
I also read reports from the French advisory committee on weapons from 1936 to 1939, but nothing out of the ordinary concerning tanks, just developments that we already knew about; bar some small info about 37mm SA 38 gun development and tank gun AP performance. More spicy for other weapon categories however.
Great detail and, as always, thanks for sharing! 👍