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).
Phantom engine performance issues, comparing fuel consumption, self-ignition, and detonation to the Silver Ghost.
| Identifier | ExFiles\Box 1\3\ B001_X 93-page46 | |
| Date | 1st March 1926 guessed | |
| contd :- -2- (1) Under full throttle conditions the Phantom engine is 16% better for petrol consumption than the Silver Ghost under similar conditions. On the road we are not satisfied that we get the advantage we should. We think it is possible that an increase in turbulence may give us better m.p.g. (2) We have had several complaints with the Phantom going on firing after being switched off. Customers have stated that it is worse than the Silver Ghost in this respect. Our tests have shewn that it is due to self-ignition of the charge. It occurs just as the engine is about to stop when the turbulence value would be its lowest. (3) Explosions in the silencer. It is possible that with more turbulence, the charge will be more completely burned in the cylinders so that this fault should be reduced. (4) We are not getting the maximum value from our oil relay ignition governor until we fire two ignition plugs and fit in such positions as to give maximum results. In view of the foregoing, we are very keen that E's suggestion of improving the combustion chamber and increasing the turbulence should be tested. The recent tests for detonation on Phantom engines have brought up the following points :- (1) It is stated by different authorities that if an engine is run detonating it will pre-ignite and over-heat. This is not the case with the Phantom. We have run an engine detonating badly for hours at a time, the power remaining constant. At the same time we have measured the heat flow to the contd :- | ||