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).
Graph of road wheel horsepower required to propel an Open Touring 40/50 car weighing 2.15 tons at various speeds.
| Identifier | ExFiles\Box 73\3\ scan0371 | |
| Date | 6th February 1923 | |
| ROAD WHEEL H.P. REQUIRED TO PROPEL AN OPEN TOURING 40/50 AT VARIOUS SPEEDS CAR WT 2.15 TONS. E.A.C. ROAD WHEEL HORSE POWER 88.5. 40/50 ROAD WHEEL HORSE POWER 65. Max Resulting Road Speed 76 M.P.H. Max Resulting Road Speed 68.5 M.P.H. Y-Axis: ROAD WHEEL H.P. X-Axis: ROAD SPEED M.P.H. W.A.R 6/2/23. | ||