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 removed from vehicle 12-EX.
| Identifier | ExFiles\Box 50\4\ Scan217 | |
| Date | 28th September 1928 | |
| X4308 28.9.28. A.T. SPEEDOMETER B.138 No.730 15/52. REMOVED FROM 12-EX. This instrument has again been tested and now reads 47.9 m.p.h. at 600 r.p.m. at 21.5°C, which is 4.8% less than the reading taken from the blueprint curve dated 24.3.28½ E.F.C. EFC. {E. Fowler Clarke - Electrical Engineer} | ||