In July of 1930, French military command decided to motorize five infantry divisions. The goal was very ambitious: these motorized units were supposed to cover 200 km in a day. Not a single existing French tank was capable of this feat. It was decided that a new vehicles must be created.
The new tank began development in 1935-1936, and was meant to reinforce infantry divisions. It was supposed to have 40-60 mm of armour, a 47 mm gun, and weigh no more than 20 tons. This was the mass that bridges and army pontoons could hold. A heavier tank would also be unsuitable for transport with trailers and railroad cars of the time.
Seven companies submitted a bid for tender. Among the competitors was Baudet-Donon-Roussel (BDR), specializing in building truck trailers. Their first prototype put the commander directly in the path of ejecting shells. With every shot, he risked injury.
No company managed to fulfil the weight requirement of the tender. Given the armour and armament required, it was impossible.
In 1938, the new tank received the designation G1. The army increased the maximum weight to 35 tons. Additionally, a 75 mm howitzer officially became the vehicle's main weapon.
The BDR company was so caught up in the secrecy of the project that even the wooden mockup was stored in a secret remote location. Because of this, the engineers could not demonstrate the mockup in time, as they did not have time to dismantle the wall behind which it was hidden.
The BDR G1B had a series of novel solutions: gun stabilizer, optical rangefinder, partial automation of the loading process. Compared to other French tanks, it could have been a qualitative leap forward, like the T-34 was for the Soviets.
The BDR G1B did not enter production for many reasons. Its mass was over 47 tons, it was too tall, Baudet-Donon-Roussel lacked the necessary production resources. None of the seven companies involved managed to complete their project.
Original article available here.