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 detonation characteristics, ignition systems, and proposed modifications.
| Identifier | WestWitteringFiles\P\October1926-November1926\ Scan016 | |
| Date | 27th September 1926 guessed | |
| contd :- -6- The detonating characteristics of this engine seem little different to those of the std. Phantom and it is unlikely that any appreciable higher compression ratio could be employed than the present 4.1 to 1. Synchronised ignition while requiring less advance than either side used singly, does not reduce the intensity of audible detonation. No difference has been appreciated between the use of one or two ignitions on the efficiency at full or reduced loads. We still experience continued firing on switching off the ignition. Because detonation is still manifest we wish to prove whether the small clearance between the piston and the head does promote turbulence and influence detonation. It should be possible to prove this by rounding off the metal of the head forming these steps and adjusting the compression ratio to the same value by means of the std. type conical top pistons. We are also arranging to test the scheme shewn on LeC. 2230 where the 'steps' for giving turbulence are wider than on the present engine. One advantage possessed by the synchronised ignition is that by virtue of the less advance required it should be easier to operate and make less demand upon the oil relay. Hs{Lord Ernest Hives - Chair}/A.C.Lovesey. | ||