Project PHOENIX

[Bob Carriere]

.... what is the diameter of a modern US bar thread 11 x 20..?

I have some at the barn and they are much taller than the usual 9x16........

with the proper large tire you can surmount the ratio differences.

Bob

[Bob Moseley (RIP)]

Hi all - the word from Mike at the AWM is as follows;

Drawing code: Army Design Directorate (Experimental)
Project code 868.
CVT: Chevrolet.

Now we have to track down Project 868.

Bob

[Bob Moseley (RIP)]

Hi all - discussions last night with my guru, Dingo Man, led us to Mike Cecil's book on Carriers. Whilst discussing the Tracked Truck we discovered that its drive sprocket was a 42 tooth sprocket. Colin and I had calculated that the Phoenix sprocket was 43 tooth, but maybe it could be 42 tooth. Next question, was any tracked vehicle fitted with a 42 tooth sprocket so that GM could utilise that as opposed to manufacturing a new one. Am I correct when I say that the Vickers Light Tank utilised Carrier tracks, and if so, how many teeth were on its drive sprocket? Also was the Vickers fitted with Pommy or Oz track?

Bob

[Richard Farrant]

Originally Posted by Bob Moseley

Also was the Vickers fitted with Pommy or Oz track?

Bob,


The Vickers Light Tank pre-dates Australian LP carriers so would be fitted with British tracks (Pommy as you say). I think this was discussed recently with Colin, but I seem to recollect the Light Tank had a slightly wider track fitted, according to an amendment in the manual dated about 1937, and also think that it is wider than a British carrier track. Can find no mention of number of teeth on the sprocket though.

[gordon]

... doesn't happen often so I thought I'd share it - maybe someone has even mentioned it before.

If you were starting to build this thing, and you had the standard chassis, transmission, diffs, wheels and tracks on the shelf, the obvious difficulty is matching the wheel drive ratio to the tracks, as per all the above discussion.

There's also been a lot of chat about the track sprocket tooth number, but wouldn't it have been a simpler option, at time of original production, to make one or more special pairs of drive sprockets with slightly different diameters and numbers of teeth? Obviously you would start by knowing what the front drive roadspeed should be, but specially-made drive sprockets would let you match or iron out any variations, within the limits of being too small for the tracks to run round or so big they hit the 'body'

Build it first, with standard carrier drive sprockets, and try it with the front axle out of gear, then measure it, then fit track sprockets with extra or less teeth till it's a perfect match with the front axle in drive?

Oh, and I hope it's going to get a real body and not that collection of concrete blocks like the original did in the photo.


Good luck.

[Bob Moseley (RIP)]

Hi Gordon - thanks for your thoughts. I think we will go with the 43 tooth sprocket. As far as the body goes I will stick with the concrete ballast body as that is how the vehicle was conceived and tested. I want to replicate as close to the original as I can.
Bob

[gordon]

If you were building it today stick with standard sprockets and leave the front axle out of gear for now.

I still think you might consider a special body too, maybe in addition to the concrete ? I expect there would be plans out there somewhere for what they intended as the final result.
Time enough for that when you get the rest of it up and running.

Gordon