I guess many people are aware that trials of different transmission systems for rhomboid tanks were carried out in March 1917.
The winner was Wilson's planetary gear transmission which was installed in the Mark V and successors.
Has anyone found the write up of the trails? Both Daimler and Westinghouse submitted petrol electric systems presumably similar to the St Chamond transmission but I've never seen any report of these.
There are IWM images of the Mark II trial tank with Williams-Janney hydraulic transmission taken at Dollis Hill in 1918 - there's limited detail visible inside the tank but the lack of the massive differential is notable. The Williams-Janney transmission was used in the Mark VII tank.
I was looking at the Mark VII tank and note that David Fletcher says it was a stretched Mark IV with Mark V rear cupola but the "New Excaliber" says it was a stretched Mark V - anyone have a definitive answer to this? Stern's book has the Mark VII with two units per track connected by hoses but this doesn't seem right the W-J transmission could be configured as a single unit.
Regards,
Charlie
-- Edited by CharlieC on Saturday 22nd of August 2026 06:11:34 AM
