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).
Experiments with Phantom carburetters concerning high induction pipe depressions and power output.
| Identifier | ExFiles\Box 5\4\ 04-page184 | |
| Date | 19th September 1927 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/ACL. c. to BJ. Wor.{Arthur Wormald - General Works Manager} 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 OY. An experimental Phantom cHs/ACLl/LG19.9.27. PHANTOM CARBURETTERS. REASONS FOR HIGH INDUCTION PIPE DEPRESSIONS. At various times we have made experiments on both the Phantom and 20 HP. to shew how the power output, particularly at high speeds, could be increased by working at a low induction pipe depression and have further proved that the power was proportional to the absolute induction pipe pressure. More recent experiments have shewn the desirability of working at a low induction pipe depression in order to gain fully such advantages as are offered by longer duration inlet cams and larger valves and so increase the engine speeds and performance of both the Phantom and the 20 HP. Experiments have been made on the std. Phantom carburetter in order to determine if an appreciable reduction in induction pipe depression would accompany enlargement of the chokes and air ports and at the same time retain a good low speed performance and pick up. The results however were disappointing and we definitely established that the power output of the engine could not be appreciably increased by altering the proportions of the std. carb. - what small gain we could obtain resulted in weak acceleration and poor slow running. Similar experiments were made on the std. 20 HP. carb. and the results were precisely the same as obtained with the Phantom. The following is a brief description contd :- | ||