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).
Tractive resistance and horsepower requirements for a touring car.
| Identifier | ExFiles\Box 160\2\ scan0037 | |
| Date | 1st February 1924 | |
| R.R. 403A (40 H) (SL 42 12-7-23). J.H. D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. Expl. No. 4578 REF: Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LCS.2.24. Tractive resistance at any speed = 23 + 3.11 (m.p.h./10)^2 at 60 m.p.h. = 23 + 112 = 135 lbs/ton. " 70 " = 23 + 152 = 175 " " 80 " = 23 + 200 = 223 " H.P. at the road wheels required to propel a RR. touring car at any give speed. | ROAD SPEED M.P.H. | TRACTIVE RESISTANCE LBS/TON. | HP. REQUIRED AT ROAD WHEELS CAR WEIGHT = 2.15 TONS. | |-------------------|------------------------------|-----------------------------------------------------| | 10 | 26 | 1.49 | } | 20 | 36 | 4.1 | } Obtained | 30 | 52 | 8.9 | } practically. | 40 | 65 | 14.9 | } | 50 | 110 | 31.6 | } | 60 | 135 | 46.6 | } | 70 | 175 | 69.8 | } Derived. | 80 | 223 | 102.5 | } Clutch H.P. 40/50 = 80 Road wheel H.P. = 65 Loss to road wheels = 18.8% Clutch H.P. EAC. = 109 Road wheel HP. allowing for similar % loss as 40/50 = 88.5. ------------------------ Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||