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).
Investigation into carburetter noise, specifically a whistling sound at certain speeds.
| Identifier | ExFiles\Box 5\4\ 04-page086 | |
| Date | 2nd February 1923 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to N. c. to Ds. c. to BY.{R.W. Bailey - Chief Engineer} CARBURRETTER NOISE. X4228 X2768 With reference to the complaints on carburetter noise, we are carrying out two lines of investigation :- (1) Arriving at a standard of silence for the present carburetters and to decide which are the vital points to watch to eliminate the noise. (2) The most convenient manner to modify the design so that the carburetter noise is still further reduced or eliminated. With regard to Item 1., we find on some carburetters, the suction noise at some speeds develops into a whistle, the noise then becomes very objectionable. There appears to be two speeds at which this whistle is liable to come on (1) at dead slow idling speeds (2) with the throttle lever opened about .125" to .175". We find in the first case the noise comes from the collars turned above the low speed jet and number 2. appears to be affected by the annular passage between the spigot on the carburetter and the recess turned in the induction pipe through the cylinder. We believe we shall be able to make carburetters which all, more or less, make the same degree of noise and will not whistle. With regard to Item 2., we have tried a 20 H.P. carburetter which was made so that the whole of the air taken into the carburetter went through a common inlet and was silenced. We find this is a certain degree of improvement. If, however, we arrange a pipe to feed the common air inlet and carry the contd- | ||