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 power output tests comparing standard and large carburettor throttle sizes and throat sizes.
| Identifier | ExFiles\Box 5\4\ 04-page152 | |
| Date | 17th February 1926 guessed | |
| contd :- -2- valve, dashpot, and spring were retained. The power curves given below are the average of several tests. The standard silencing arrangements were used. | R.P.M. | B.HP. Std. pipe and carburetter. | B.HP. 1.5 dia. pipe and large throttle. | |---|---|---| | 2750 | 49.3 | 49.3 | | 2500 | 48.5 | 48.5 | | 2000 | 42.5 | 42.5 | | 1800 | 33 | 32.8 | | 1000 | 23 | 22.8 | | 500 | 11.15| 11.15| Barometer 751 m/m 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 max dia. Allowing for the jet sizes this results in 75% increase in area. The results was an increase in maximum power of 2½% or only 1¼ HP. at 2750 r.p.m. obtained with the larger throat. Again, the same air valve and spring were contd :- | ||