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).
Notes on modifying a carburettor needle and diffuser to cure whistling and suction noise.
| Identifier | ExFiles\Box 5\4\ 04-page094 | |
| Date | 5th February 1923 | |
| 3. cured by removing the top step of the 'petrol diffuser' portion of the needle. [Diagram of a carburettor needle] Remove shaded portion to cure low speed whistling. An attempt was then made to cure the suction noise, a source from vibration by fitting a semi-spherical shaped baffle over the air intake*. This reduced the suction noise considerable. This baffle caused no loss in power whatever, the carburettor was put on test-bed engine for this purpose. A standard low speed needle valve was then put on the carburettor and accurately set. It was then removed and filed as above, afterwards being replaced. The effect of removing a portion of the diffuser is to move the previous 'normal' running position 1 1/2 notches further on a standard carburettor quadrant. [Signature] A.J. Lidsey 5/2/23. [Signature] Segall [Side note] * c/model handed to D.O. | ||