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).
Engine roughness and performance compared to the standard Wraith model.
| Identifier | ExFiles\Box 109\5\ scan0121 | |
| Date | 10th March 1939 | |
| -2- LAll/T10.3.39 Generally we should say that the engine is slightly more rough than the standard Wraith, but not very marked. It does not appear to be any more liable to detonation, neither do we consider that a customer would object to the slow running obtained. L.A.H. | ||