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 comparison data for a Wraith before and after modifications to the camshaft and pistons.
| Identifier | ExFiles\Box 109\5\ scan0126 | |
| Date | 11th March 1939 | |
| 664 To By.{R.W. Bailey - Chief Engineer} c. to Mx.{John H Maddocks - Chief Proving Officer} c. to LA.{L. A. Archer} Rm{William Robotham - Chief Engineer}/FD.{Frank Dodd - Bodies}2/JH.11.3.39. W.A.I. "G"s. Wraith. Performance figures before and after having a Bentley camshaft, and raised crown pistons fitted with 6.5 comp. ratio. 3.34 axle. 6.50 x 17 tyres. Before. 10 - 30 - 9.35 secs. 10 - 40 - 14.7 secs. 10 - 50 - 20.05 secs. 10 - 60 - 29.55 secs. 10 - 70 - 42.27 secs. After. 9.28 secs. 14.5 secs. 19.75 secs. 27.0 secs. 36.25 secs. ******** Before modification. Maximum speed on six Hills, average of both ways. m.p.h. 79.5 After modification. Maximum speed on six Hills, average of both ways. 82. Neither the acceleration figures nor the max. speed should be taken as correct as the speedometer was not corrected, and only used for a comparative test. Rm{William Robotham - Chief Engineer}/F.Dodd. | ||