Question about CMP winch?

Barry Churcher · #1 30-10-09, 01:52

Phil, I don't have the correct answer to your query but I do know that if the winches are heavily loaded the frame will twist before anything breaks. When I was working on my artillery tractor I went through three badly twisted chassis before I found a good one. The best chassis came from a truck that had spent it's life as a tow truck.
Cheers,
Barry

Grant Bowker · #2 30-10-09, 03:47

Vol 4 of the AEDB Design Record lists the capacity for the chassis winch as "The maximum pull developed by this winch is 11,000 pounds with a ratio of 6.2 to 1 in the winch drive unit."
From the same source: "125 feet of 5/8" diameter cable was normally fitted on this drum."
Yet another, different answer.......

Lynn Eades · #3 30-10-09, 06:48

Back then ,I would say your winch is rated in long tons. Short tons were used for shipping purposes.
Now Tony's going to say something profound

Tony Smith · #4 30-10-09, 07:02

Or we can try to calculate it?

The Ford Engine makes 178 ft lbs of torque. Multiply by 6.4:1 1st gear gives 1139.2 ft lbs. Multiply by the winch ratio of 6.66:1 gives 7587 ft lbs. What is the diameter of the winch drum? If we hypothetically say the layer of cable is 8 inches from the centreline if the drum (divide by .66), that gives us 11495 lbs of pull.

The Chev engine will have different torque (170 ft lbs @ 1200) and gear (7.058 to 1) figures, and the actual diameter of the drum needs to be measured, but are we in the ballpark?

Phil Waterman · #5 30-10-09, 18:59

Quote:

Originally Posted by Barry Churcher

Phil, I don't have the correct answer to your query but I do know that if the winches are heavily loaded the frame will twist before anything breaks. When I was working on my artillery tractor I went through three badly twisted chassis before I found a good one. The best chassis came from a truck that had spent it's life as a tow truck.
Cheers,
Barry

Barry - You hit the nail on the head about hard use, this particular 1941 C60L had been hard used and abused. It spent part of its life building Mount Ascutney Ski Area in Vermont, from the cable reel frame on the back it was used to drag cable up the mountain. It had been rolled at one point bending the cab frame and brake peddle, the clutch housing had so many cracks in that when you tapped it with a hammer it went thud.

The winch guides all showed evidence of hard use and have actually been worn by the cable pulling across them. Given all that one of the first things I did was check all the diagonal measurements across the frame and the silly thing was straight and flat.

In parts of the world where there are multiple CMPs to choose from I'm sure that this one would have been considered a parts truck.

Phil Waterman · #6 30-10-09, 19:27

Quote:

Originally Posted by Barry Churcher

Phil, I don't have the correct answer to your query but I do know that if the winches are heavily loaded the frame will twist before anything breaks. When I was working on my artillery tractor I went through three badly twisted chassis before I found a good one. The best chassis came from a truck that had spent it's life as a tow truck.
Cheers,
Barry

Barry - You hit the nail on the head about hard use, this particular 1941 C60L had been hard used and abused. It spent part of its life building Mount Ascutney Ski Area in Vermont, from the cable reel frame on the back it was used to drag cable up the mountain. It had been rolled at one point bending the cab frame and brake peddle, the clutch housing had so many cracks in that when you tapped it with a hammer it went thud.

The winch guides all showed evidence of hard use and have actually been worn by the cable pulling across them. Given all that one of the first things I did was check all the diagonal measurements across the frame and the silly thing was straight and flat.

In parts of the world where there are multiple CMPs to choose from I'm sure that this one would have been considered a parts truck.