US Twin V8 Tractor

[Richard Farrant]

Originally Posted by Tony Smith

Does anyone know what these were?

US Army twin Ford V8. The 2 engines were synchronised by driving 2 differentials with a linked axleshaft in the middle. I don't see how power was then transmitted to the rear bogie.

Hi Tony,
I think your photo of the truck with two engines mounted on the back driving a double diff axle is misleading. Look at the rear view of the Army truck and you will see the 3rd axle diff offset to left, so left hand engine drives that axle. My guess is the 2nd axle has diff offset to right. So drive is much simpler than we thought. I am also confused about the centre photo, but maybe it is just someone's idea to build a display engine set up.

regards, Richard

[Tony Smith]

The photo was from a forum that described it as the powertrain from the type of pictured tractor unit. Of course, the single gearstick shows that it is not probably a complete assembly, and you're right, it is now more likely to be someone's concept of how it could have been!

The two co-joined differentials had me confused, as with the inherent behaviour of Open Diffs, when power was applied to the two pinions, the rpms would have been equalised, but instead of forward torque being applied to the outer axleshafts, the middle shaft would have rotated freely in reverse! No go, Joe. This could have been rectified by one of the differentials being either a solid spool or a traction locking device, but that would have eliminated the rpm equalising. Very strange display piece, but who wouldn't love 2 V8s in sync?