Citation

Saal CC, Cherniack N, Burch JS. Highw. Res. Board Proc. 1938; 1938.

Copyright

(Copyright © 1938, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

The hill-climbing ability of some 30 new trucks was determined. Methods were as follows: (1) grade tests, (2) theoretical performance, (3) acceleration and decelerated tests, and (4) drawbar dynamometer. Conclusions were that (1) testing under actual load conditions over several grades provided results of the greatest accuracy; however, this method was so laborious and expensive as to preclude its general usefulness, (2) computation of grade ability from the manufacturer's torque curves, provided reliable factors for overall efficiency and rolling resistance at various speeds yielding reasonably accurate results, (3) computation of grade ability from acceleration and deceleration tests yielded accurate results, especially in the more generally used range of engine speeds, and required no data from the manufacturer; complete tests required but a few hours in the field, but office computations were laborious. The method was far cheaper than the actual grade tests, and (4) the towing dynamometer produced accurate results quickly and in a usable form. Their high initial costs limited their large use to operations requiring the testing of a large number of vehicles quickly.