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 report on the torsional period, engine RPM, and speedometer accuracy for the 20-EX model.
| Identifier | ExFiles\Box 137\4\ scan0163 | |
| Date | 9th January 1931 | |
| X634 FOR FILES. 20-EX. 9.1.31. 2.125 Crank Pins. Journals 2.625 82.M.P.H. X.7010. 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. | ||