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).
A.T. Speedometer test record showing performance at different temperatures.
| Identifier | ExFiles\Box 59\2\ Scan078 | |
| Date | 8th October 1930 | |
| X4308 A.T. SPEEDOMETER TEST RECORD. Date :- 8.10.30. Speedometer :- D.231 74C. 11/50. Remarks :- Fitted on 18-GIV on 10,000 mile change of reading test. Drive counter Counter revolutions per mile 742.5 (found by actual trial). Correct miles per hour reading when driven at 600 r.p.m. :- 48.5 Temperature (°C) M.P.H. indicated at 600 r.p.m. exactly. 16.0 47.2 20.0 46.8 22.0 46.6 24.0 46.4 26.0 46.2 28.0 46.0 30.0 45.8 32.0 45.6 Percent fall of reading between 20°C. and 30°C. .2.1..... 9.10.30. | ||