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).
Letter providing a provisional specification and recommendations for a raised crown piston for a Leyland engine.
| Identifier | ExFiles\Box 148\1\ scan0085 | |
| Date | 28th March 1939 | |
| 1256 Rm{William Robotham - Chief Engineer}9/R.{Sir Henry Royce} 28th March, 1939. J.{Mr Johnson W.M.} Howlett, Esq., Wellworthy Piston Rings Limited, LYMINGTON, Hants: Dear Howlett, Herewith is the provisional specification for raised crown piston, together with our recommendations for the Leyland job. If Leylands are already running 6.6 with their engines they ought to be able to go up a complete ratio with a raised crown piston, i.e., 7.6. On the other hand, this seems to be a very high compression for an engine which has to run on commercial fuel. Possibly we have made a mistake in assuming that the original ratio on the Cub was 6.6, but this was all we could calculate from the drawing. I enclose a print which shows all the major proportions of the piston and the combustion chamber with which we have been so successful. Yours sincerely, | ||