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).
Test results for an A.T. Speedometer (14-EX) showing M.P.H. readings at various temperatures.
| Identifier | ExFiles\Box 50\4\ Scan153 | |
| Date | 19th November 1927 | |
| 4306 19.11.27. A.T. SPEEDOMETER (14-EX). TEMP. M.P.H. at 600 r.p.m. 18°C 45.1 18°C 44.9 20°C 44.3 22°C 43.3 24°C 42.1 26°C 42.0 28°C 41.3 30°C 40.8 32°C 40.3 34°C 39.6 Initial observations taken at end of 30 mins. (for warming up of disc). At full speed of 1200 r.p.m. reading is 79.0 m.p.h. at 34°C. Speedometer should read 47 m.p.h. at 600 r.p.m. EFC. {E. Fowler Clarke - Electrical Engineer} | ||