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).
Bench test results for an A.T. Speedometer from chassis 19-EX, showing MPH readings at various temperatures.
Identifier | ExFiles\Box 59\2\ Scan047 | |
Date | 1st July 1930 | |
X4308. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} from EFC. c. Hs{Lord Ernest Hives - Chair}/AJL. EFC2/ADL1.7.30. 47.1 X.4308. A.T. SPEEDOMETER No. D.668. 765. 11/41. ex Chassis 19-EX. This instrument, which has been handed to us from 19-EX, has been tested on our bench apparatus with the following results :- The counter revolutions per indicated mile, namely 765, were found to be correct. Driven at 600 R.P.M. exactly the instrument was found to give the following readings in miles per hour at the temperatures quoted :- Temperature (°C) M.P.H. indicated. 20.0 47.7 22.0 47.5 24.0 47.3 26.0 47.1 28.0 47.0 30.0 46.8 32.0 46.7 35.0 46.5 The correct figure of miles per hour when driven at 600 R.P.M. is 36000 / 765 = 47.0 The instrument is therefore seen to be correct at a temperature 28°C. and to read slightly low at higher temperatures and conversely. | ||