Ok here's a long and confusing question. I hope the experts can help or
curiosity may kill this cat.
Q: How is Maximum Gradability of a vehicle computed?
Many MV books, such as TM 9-2800, list a vehicle's maximum gradability, ie
maximum grade the vehicle can climb. Gradability is given in percent of
slope. I understand how to convert "degree of angle" to "percent of
slope". But is every vehicle actually tested to see how steep an angle
(slope percentage) it can climb? Is the test performed at rated load or
empty?
I suspect there is a formula for figuring this, but what is it? Or is each
vehicle in fact tested? Or does someone make a "best guess" for each
vehicle?
Some examples from TM9-2800:
* CCKWs listed as 65% regardless of wheelbase or body style EXCEPT the 750
gal tanker listed as 84% .
* Chevy 1 ton 4x2 truck listed at 66% but Dodge WC51 4x4 listed as only
60%.
*Car, Light Sedan, 5 passenger, 4x2 made it to 38% while the enormous
Autocar U-8144-T 5-6 ton ponton tractor could only muster 30%. CAT D6
made only 36%, that's less than the staff car!!
*And of course the M-29 Weasel made standard at 100%. MB pulled 60%.
Jane's Military Vehicles and Logistics 91-92 lists:
* Hummer 60%, M35A2 60%, M54 50%, M52 77%, M715 58%, M38 65%,
M38A1 69%, M151 60%and M37 68%.
If there is a formula, it must be based on weight vs horsepower. That's
the only way I can figure the General's staff car is going to pull a
steeper grade than the SeaBee's D6 Cat. But is traction a factor? Is 4x4
vs 4x2 factored in? Wheels vs tracks?
Comments or gradability formula gladly accepted and shared:
Thanks and Aloha from sunny Honolulu,
Bob
===
To unsubscribe from the mil-veh mailing list, send the single word
UNSUBSCRIBE in the body of a message to <mil-veh-request@skylee.com>.