From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Rolling resistance of wheels, including a formula used by General Motors.
| Identifier | ExFiles\Box 159\7\ scan0218 | |
| Date | 31th October 1938 | |
| 1375 EV{Ivan Evernden - coachwork}: from Hs{Lord Ernest Hives - Chair}/LS. Copy to EV{Ivan Evernden - coachwork} and Rm.{William Robotham - Chief Engineer} Hs.{Lord Ernest Hives - Chair}/LS.6/T31.10.38 FJH{Fred J. Hardy - Chief Dev. Engineer} Rolling Resistance of Wheels. I was not able to get very much information on this subject in America. General Motors use the formula :- AH? R = .0112 W plus .000097 W V.{VIENNA} Where R = resistance in lbs, W = curb weight in lbs, V = car speed in mph. For smaller cars the constant 97 appears to be too high and for instance, they use 80 for the Chevrolet. I attach to EV{Ivan Evernden - coachwork}'s copy this relationship superimposed on the curve, giving Andreau's results. General Motors have no knowledge of any rapid rise in the power of 'V' in the formula at high speeds, apart from that due to the acoustic wave phenomenon, on which I have previously reported. Hs{Lord Ernest Hives - Chair}/LS. | ||