Here's a pic from an old book that I've had for many years that details various bits of electrical engineering from over 100 years ago, and one example which fascinated me was a transmission for a vehicle that did away with the gearbox. There were various petrol-electric systems around but this one was interesting in the way it worked and was in fact the basis of the present day hybrid transmission. It was patented in 1908 by Frank Thomas, who was Chief Engineer at Leyland before he left to pursue a career as a racing driver. Better known as Parry Thomas, he was sadly killed during a land speed record attempt on Pendine Sands in Wales.
The truck in the pic is loaded with bags of cement, so the all up weight is anyone's guess, probably a fair bit. The engine in it ran at a constant speed and the power was split between driving the truck mechanically and driving the trailers electrically by means of motors on the axles.
There was no gearbox, the speed was regulated by controlling the electric motors. As the engine was running at its most efficient speed it was quite economical, in fact in 1912 a fleet of buses in the Bournemouth area fitted with this transmission were averaging 10.5 mpg which wasn't bad for those old petrol engines on stop-start work.
Anyway, back in 2008 I'd been retired a few years and caught up with all the things I'd been meaning to fix and been where we'd been thinking of going for ages when I came across this book again, so I thought I'd have a go at replicating this transmission. ( To be continued )