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).
Performance graph comparing dynamometer and bench horsepower against RPM.
| Identifier | Morton\M7\ img072 | |
| Date | 14th February 1923 guessed | |
| ...OMETER HP GII BENCH HP GII DYNAMOMETER 50 1500 R.P.M. 1750 2000 | ||