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).
Investigation into engine detonation on Phantom engines, comparing them to the Silver Ghost and identifying lack of turbulence as the root cause.
| Identifier | WestWitteringFiles\O\2January1926-March1926\ Scan153 | |
| Date | 11th March 1926 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/ACL. c. to CJ. BJ. c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} oY Hs{Lord Ernest Hives - Chair}/ACL1/LG11.3.26. 493 X8230 DETONATION ON PHANTOM ENGINES. We have recently been investigating the problem of detonations on the Phantom engines. Detonation is our limiting factor on this engine which prevents us from increasing the efficiency. The compression ratio on the present Phantom cars is approximately 4 to 1. This is practically the same as we used on the Silver Ghost. As regards detonation we should say that there is very little improvement on the Phantom with its more compact combustion chamber compared with the Silver Ghost when we fire with the intermediate plug. In our opinion, the reason the Phantom engine is not as good as one would anticipate for absence of detonations, is because of the lack of turbulence at the time of ignition. This is proved by the amount of maximum ignition advance required on this engine. It is also confirmed by the fact that when we fire two plugs on different sides of the cylinders, the optimum ignition point on each plug is very different. We have therefore come to the conclusion that to improve the Phantom engine we should make every endeavour to increase the turbulence in the combustion chamber. Apart from detonation, there are several other features which we think might be improved if we only increase the turbulence. contd :- | ||