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 curing a low speed whistle and suction noise from a carburettor.
| Identifier | ExFiles\Box 5\4\ 04-page089 | |
| Date | 5th February 1923 | |
| contd:- -2- [Handwritten note next to diagram] This space must be filled up to prevent whistling. [Text on diagram] CARB. TUBE The low speed whistle was then investigated and found to be proceeding from the low speed jet venturi. This whistle can be cured by removing the top step of the 'petrol diffuser' portion of the needle. [Handwritten note next to diagram] Remove shaded portion to cure low speed whistling An attempt was then made to cure the suction noise, as distinct from whistling by putting a hemispherical shaped baffle over the air intake (model handed to D.O.) This reduced the suction noise considerably. This baffle causes no loss in power whatever, the carburetter was put on the test bed engine for this purpose. As standard low speed needle valve was then put in the carburetter and accurately set. It was then removed and filed as above, afterwards being replace. The effect of removing a portion of the diffuser is to move the previous 'normal' running position. 1 1/2 notches weaker on a standard carburation quadrant. A.J.Lidsey. 5.2.23. TMW. | ||