US Twin V8 Tractor

[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.

[Richard Farrant]

Hi Tony,
By coincidence I put a photo of one of these in last month's AMVCS newsletter. They were used for moving aircraft components and assemblies between plants as I recall, and could have been involved with jeep production. Memory tells me there was an article in Wheels and Tracks many moons ago.

regards, Richard

The photo is of one moving aircraft assemblies, possibly wings or fuselages at a guess, it is dated as 1943.

Just found more info, I remember now, it was not built by Ford, http://blog.hemmings.com/index.php/2...-flathead-fun/

[Keith Webb]

Yes they were designed to transport major assemblies of B24s to Ford's Willow Run assembly plant.

The twin engine power pack was mounted on rails to allow for easy changeovers.

There's an extensive article in one of the Wheels and Tracks issues.

[Brian Gough]

Hi Keith

Found it. These trucks were actually covered twice in Wheels & Tracks articles:
Issue 7 p. 29 - 31 and Issue 16 p. 21 - 23. Good reading and lots of pictures.

Cheers,

Brian

[gordon]

Originally Posted by Tony Smith

Does anyone know what these were?

I don't see how power was then transmitted to the rear bogie.

I think there was more than one manufacturer in that configuration - THORCO is the one I remember, but other similar units were featured in Fred Crismon's U.S. Military Wheeled Vehicles too. I vaguely recall each engine had its own transmission and drove just one of the rear axles - basically two separate power trains.

Not to be confused with GRICO, who did a similar conversion for a similar purpose, but it had one engine under the cab and another in a pod behind the cab, basically two engines inline as opposed to side by side.

Nice me a minute and I'll find the WAI thread.

Here you go;

http://forums.justoldtrucks.com/4985...14?PageIndex=2

[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?