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).
Unsuitability of a 6:1 compression ratio for a production Phantom II vehicle.
| Identifier | Morton\M19\ img195 | |
| Date | 1st June 1931 | |
| To R.{Sir Henry Royce} from HS.{Lord Ernest Hives - Chair} c. Sg.{Arthur F. Sidgreaves - MD} c. Wor.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} c. Da.{Bernard Day - Chassis Design} HV. ORIGINAL 87770 87771 PHANTOM II. 6 : 1 COMPRESSION RATIO. In a recent memo you asked for P.2. to be fitted up with 6 : 1 compression ratio. We have no cylinder head which will give us this ratio. We have modified the present one so that we can obtain 5 : 1 instead of the standard 4.6 : but to make it suitable for 6 : 1 we think the design should be gone into. We are certain that we shall never be able to use a 6 : 1 compression ratio on a car which we could sell to a customer. It would only be useful purely on a car to run on the track with special fuel. In our opinion a compression ratio of about 5½ : 1 is about as high as we can go on the P.2. If you wish us to carry on with 6 : 1 ratio we should like a scheme showing how it should be arranged. HS.{Lord Ernest Hives - Chair} | ||