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).
Comparing the petrol consumption and performance of a 59.9 HP Napier and a 48.4 HP Rolls-Royce Silver Ghost.
| Identifier | ExFiles\Box 20\6\ Scan013 | |
| Date | 17th October 1910 | |
| B 17th October 1910. Mr. Johnson. Re Petrol Consumption. 59.9 H.P. Napier. Consumption over 799 miles from London to Edinburgh and back at an average speed of 20.2 m.p.h...........19.85 m.{Mr Moon / Mr Moore} per gl.{G. Linnett} or 42.57 ton miles per gall. Total running weight.........................4928 lbs. Wind resistance area of body..................10.4 sq. ft. Speed at 1000 r.p.m. on top gear (assum-ing 34 inch wheels)..........37 m.p.h. 48.4 H.P. Rolls-Royce (Silver Ghost). Consumption over 420 miles from Hatfield to Glasgow, (average speed unknown)......................20.8 m.{Mr Moon / Mr Moore} per gl.{G. Linnett} or 40.8 ton miles per gall. Total running weight.........................4882 lbs. Wind resistance area of body..................unknown. Consumption over 46 1/2 miles...................23 1/4 m.{Mr Moon / Mr Moore} per gl.{G. Linnett} or 45.8 ton miles per gall. Speed at 1000 r.p.m. on direct third gear. 37.88 m.p.h. X983 | ||