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).
Renault acceleration curves and horsepower calculations.
| Identifier | ExFiles\Box 32\2\ Scan062 | |
| Date | 21th March 1925 | |
| R.R. 493A (50m) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. Expl. No. REF Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG21.3.25. RENAULT ACCELERATION CURVES. When any car is being driven along the road en full throttle at anything below its maximum speed, the H.P. at the road wheels is being used up in two ways :- (a) By keeping the car moving along the road against the wind resistance and tyre resistance (see Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LG6.2.24.) (b) All the horse power left over after this goes to accelerating the car. 'The Motor' gives the acceleration figures and the weight of the car. From this we calculate the excess H.P. used for acceleration at each speed. We know the tractive resistance in lbs/ton of our touring cars, we know by the maximum speed that these are about correct - we have assumed that the closed Renault has the same resistance per ton. This is only conjecture, but we do not believe it can be far wrong. From this assumption we have calculated the road wheel H.P. required to drive the car along the road. Converting both these curves to flywheel horse power by allowing for the tyre and transmission losses which are a known percentage, and adding them together, we get a curve for the flywheel H.P. of the engine. It will be observed that the curve is markedly concave up to 2000 r.p.m. This is the result of the acceleration being given as constant, and will be the case no matter what we take the car tractive resistance to be, the result of a straight line 'A' and a curve of the shape contd :- | ||