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 compression ratios for 4-cylinder engines in relation to post-war fuels.
| Identifier | ExFiles\Box 134\5\ scan0068 | |
| Date | 7th July 1941 | |
| 1133 To Jmr. from Bm. Bm.6/ST.7.7.41. Our experience on the 75 mm. bore 4-cylinder suggests that 6½:1 ratio is enough at any rate until we know more about post war fuels. One other point. I think that 4-cylinder engines should basically have lower compression ratios than 6 or 8, owing to the greater difficulty of supressing torque reaction. Bm. | ||