Thoughts

[David_Hayward (RIP)]

Moderator's note: this thread was split from my C15 restoration:

In answer to Bob Carriere's comments about the chassis back in August 2006, it is my theory that GM Canada took a civilian pick up truck chassis of probably US origin and modified it to suit the CMP cab. The C15 chassis measures 36" between the outsides of the frame rails whereas the C15A and every other Chevrolet CMP measures 34" between the outsides of the rails.

This is something that I have mulled over myself for some years now. However whilst Oshawa may have used components from a pick-up, the 101" wheelbase is arguably a pure Ford "design", from the COE 011W or 091W, and the other chassis wheelbases conform with other COE Fords. This is not surprising as it was Sid Swallow's department in Windsor that designed the '40 Ford 15-cwt GS trucks for the DND and then the # 11 CMP trucks/lorries. The CMP designs were all forward-control in British parlance, to conform with WD Spec. 36E which was the last one issued in early 1939 out of Woolwich. If you check the civilian Chevrolet wheelbases you will see that the 1/2 tonner was 113 1/2" in 1940 and 115" 1941-5. The shortest COE lorry was 109 1/4".

I should add here that it was found that a COE was required by 1938, and that heavy duty components were required. Whilst no doubt the 8-cwt CMPs could get away with civilian style components, the heavier designs needed components from the heavy lorry parts bin.

However if you want more definitive proof to chew over, let's go back to the 50 1938 15-cwt GS trucks ordered from Oshawa by the DND, that were the direct predecessors of the 1940 Ford GS trucks. They were officially Model 1531, or 3/4 to 1 ton Chassis with Flat Face Cowl with a 131 1/2 inch wheelbase. However the known build plate off a survivor reveals that they were a bitza, actually Model 1752, namely 2 1/2 ton COE Chassis with Cowl, 108" wheelbase! This was near the Morris-Commercial / Guy Ant chassis lengths which were also rated at 15-cwt. In other words setting down for the future the use of civvy style chassis.

However these trucks were a dead-end in the evolutionary process. I will post a photo of a 1940 15-cwt Ford GS and you can see that Ford of Canada adopted the forward-control (from the US COE Fords) which was then taken further for the CMPs.