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).
Note on the compression ratio and engine detonation of an Essex car.
| Identifier | Morton\M1.7\ img011 | |
| Date | 20th October 1921 | |
| To R.{Sir Henry Royce} from E.{Mr Elliott - Chief Engineer} (strikethrough on 'To R.{Sir Henry Royce}') Copy to HS.{Lord Ernest Hives - Chair} ORIGINAL E1/G19/10/21. RE "ESSEX" CAR. X8317 The compression ratio of the Essex engine is 4.95 to 1. The engine readily detonates although clean. [STAMP TEXT] E.{Mr Elliott - Chief Engineer} F C OCT 20 RECEIVED | ||