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 performance issues related to the induction system and carburetter proximity to the exhaust on the Phantom model.
Identifier | WestWitteringFiles\T\2January1929-June1929\ Scan050 | |
Date | 21th January 1929 guessed | |
Hs{Lord Ernest Hives - Chair}/ACL1/T21.1.29. -4- Contd. On the Phantom with the induction system, carburetter and autovac arranged with such proximity to the exhaust system, the whole system becomes very hot under normal working conditions due to radiation and conduction. The fuel reaches a high temp. as instanced by the boiling or 'gassing' troubles we have experienced in the float chamber. The carburetter jets are set during road tests to suit these average temperature conditions which means that there is a wide difference in mixture strength between the normal running and cold engine conditions. This fact accounts largely for the reason why we require very quick warming up of the hot spot on the present Phantom; the unstable cold running being due to excessive weakness more than poor distribution. These facts are borne out by test bed experience where the temperature range of the carburetter and intake air is considerably narrower than when enclosed under the bonnet. It is found under these circumstances that the cold starting and running immediately following the start is better than on the car and approaches much nearer to the normal operation. Our F.{Mr Friese} aero carburetters in the 'Vee' afford another example of this, where it is found that their running and acceleration is very nearly as good during the warming up period as when the engine reaches normal temperature. The new S.S. engine certainly scored an advantage in this respect, having the induction system and carburetter removed to the opposite side to the exhaust and in this position | ||