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).
Carburetter throttle and throat size experiments and their effect on engine power output.
| Identifier | WestWitteringFiles\O\2January1926-March1926\ Scan120 | |
| Date | 15th January 1925 guessed | |
| contd :- -2- retained. The power curves given below are the average of several tests. The standard silencing arrangements were used. B.HP. | R.P.M. | Std. pipe and carburetter. | 1.5 dia. pipe and large throttle. | |---|---|---| | 2750 | 49.3 | 49.3 | | 2500 | 48.5 | 48.5 | | 2000 | 42.5 | 42.5 | | 1500 | 33 | 32.8 | | 1000 | 23 | 22.8 | | 500 | 11.15 | 11.15 | Barometer 751 m/m.{Mr Moon / Mr Moore} Air intake temperature 22°C. This is conclusive proof that we cannot obtain increased power output by using a large carburetter throttle and induction passage on the present engine. THROAT SIZE AND POWER. In order to estimate the amount it would be possible to increase the power by increasing the carburetter throat size we compared the respective power outputs obtained with the std. (.625 dia.) high speed throat and one of .750 dia. Allowing for the jet sizes this results in 57% increase in area. The result was an increase in maximum power of 2½% or only 1¼ HP. at 2750 r.p.m. obtained with the larger throat. contd :- | ||