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 the 20-EX model, detailing Torsional Period, RPM, MPH, and speedometer checks.
| Identifier | ExFiles\Box 14\2\ Scan094 | |
| Date | 9th January 1931 | |
| FOR FILES. X/7010 20-EX. 9.1.31. 2.125 Crank Pins. Journals 2.625 X.7010. 82.M.P.H. X.634. The master Torsional Period on 20-EX begins at 3760 R.P.M. that is 100.M.P.H. on Top gear. The speedometer has been checked in 3 different methods all of which correspond. The top R.P.M. reached with the engine is 4075, which equals 107.5 M.P.H. on Top gear. Although there was only a difference of 1.M.P.H. between the two results on the first gear according to the speedometer, as tested. I.A.Leslie. | ||