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 noise, comparing different types of throttle valves.
| Identifier | ExFiles\Box 5\4\ 04-page087 | |
| Date | 5th February 1923 guessed | |
| contd:- -2- entrance to the pipe half-way along the chassis, the noise from the carburetter is entirely eliminated. It is not until one arranges the air inlet in this way that one realises the amount of noise which is coming from the carburetter the whole time. We have also carried out tests by driving the engine and comparing a butterfly valve, piston throttle valve, and a Claudel Hobson type throttle valve. We find there is nothing to choose in the noise made by these various kinds of throttles. We were under the impression that the piston type throttle valves used on the 40/50 was more silent, but the motoring tests we have tried, do not confirm this. We believe, the reason we get less noise from the 40/50 is because we have three separate air inlets and the low speed throat inlet being on the other side of the engine, helps. If one is critical, one can notice a considerable amount of noise coming from the 40/50 carburetter but as it is a soothing noise, it is never complained of. He. | ||