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).
Compression ratios for post-war 40/50 HP chassis cars.
| Identifier | ExFiles\Box 181\M11\ img145 | |
| Date | 25th February 1919 | |
| To EH. from R.{Sir Henry Royce} Copy to CJ. C/R OF POST WAR 40/50 (LOW & HIGH COMPRESSION ORIGINAL 25th February, 1919. R6/G25219. 2H RE 40/50 H.P. CHASSIS. COMPRESSION RATIOS. We have telegraphed you to-day that we think the compression of the post-War cars, considering we are using aluminium pistons, should not be less than 4.33 to 1 for the higher compression, equalling 22¼ cubic inches, and not less than 4 to 1 equalling 25 cubic inches, for the lower compression. I agree that standard carburettor opened out would be better than the very large carburettor. I do not know exactly what you have done with reference to the size of the induction pipe, and to the method of heating the induction pipe. I have the impression that it was found that a smaller pipe was rather better in the old days. just before the war R.{Sir Henry Royce} JTR D 27 FEB 1919 RECEIVED | ||