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 of Buick and standard pistons at various compression ratios on a 25/30 unit.
| Identifier | ExFiles\Box 134\1\ scan0066 | |
| Date | 21th December 1937 | |
| -7- Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards}2/AP.21.12.37 II. 25/30. In order to see whether the performance on the Bentley unit was due to the shape of the head, the pistons were run in a bored out 20/25. unit with an open type head, this time making a direct comparison at a compression ratio of 7.42. Silenced power figures and non-detonating lines are shown in Fig.Vl.{V. Lewis / Mr Valentine} and Vll., where it will be seen that results [Graph Text] - BUICK TYPE PISTONS - FIG VI. SILENCED POWER CURVES ON 25/30 UNIT. STANDARD PISTONS CR{Mr Cra???ster / Mr Chichester} = 7.4 BUICK PISTONS CR.{Mr Cra???ster / Mr Chichester} = 7.4 STANDARD PISTONS CR{Mr Cra???ster / Mr Chichester} = 6.0 B.M.E.P. B.H.P. R.P.M. - E.D. 10.12.37 See Page 8 for Fig.VII. | ||