g3_josh wrote:
>
> I've got a simple problem for y'all but it its going to have a
> complicated answer. Let me set up a senario: You've got a
> rope,cable,chain, or other pulling device that (ignoring shock
> loading) has a break strength of 40,000 lbs. How large of a vehicle
> can I "get unstuck"? Specifically though I'd like to know how much
> force to pull a fully loaded tractor-trailer (semi) full of beets out
> of mud (up to its axle).
>
> I realize that this depends on the how the vehicle is stuck, what it
> is stuck in, how deep, whether or not the vehicles wheels are able to
> role, etc...
> A better question might be:
>
> How much pulling force, without "jerking" or "getting a run at it",
> can a vehicle produce under ideal circumstances.
> 4X4 Pickup Truck?
> Semi?
> 2WD Tractor?
> 4WD Tractor?
> Dozer?
>
> Tractor manufacturers sometimes give a PTO HP or even a draw-bar HP
> but I can't get a draw-bar pulling force from HP (without a few more
> details). Taking engine torque and multiplying it by the drive ratio
> seems like perhaps the only way to get somewhat close (although
> perhaps a bit exaggerated).

Assuming all have about equal traction, pulling force would be fairly proportional to the pulling vehicle's weight. Make a guess of the ground's coefficient of friction (0 - 1 is typical) and multiply by the vehicle's weight for a pulling force. A dozer
would probably be the best with the crawler tracks increasing the traction over pneumatic tires.

--
Roger