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).
Various unsuccessful attempts to hydraulically quieten a noisy valve experiencing a 'squawk'.
| Identifier | ExFiles\Box 151\2\ scan0252 | |
| Date | 19th June 1934 | |
| -2- Hs {Lord Ernest Hives - Chair} /WB. {Mr Brazier / Mr Bell} 10/KW.19.6.34. Another fairly successful attempt at quietening the valve was accomplished hydraulically, by drilling a small hole from each pressure chamber, to its respective section of the split valve, although its success was thought to be partly due to a slight internal leakage due to the shortness of the valve guide. A feature of this leak however was that it was cut off when the valve was seated. Thus rolling on corners would be prevented, according to previous theories. This scheme is shown in Hs. {Lord Ernest Hives - Chair} 1406B. In another attempt, the two sections of the valve were entirely separated, but controlled by one spring - Hs. {Lord Ernest Hives - Chair} 1406C - so that each section would exeAero Enginert a side pressure upon the other section of the valve during operation. However, owing to the distance required between the centres, the valves jammed, but even when it did work correctly the "squawk" was still evident. Then an entirely different type of valve was evolved, whereby the oil was released from chamber to chamber via a slotted sleeve, which was operated by what was normally the valve. The taper of the latter was made parallel, and was allowed to protrude slightly into the L.P. chamber, so that, even at maximum lift no oil could flow through the normal L.P. valve seat, as shown in Hs. {Lord Ernest Hives - Chair} 1406D. This scheme proved to be very disappointing, for it was expected that the pressure on the sleeve would damp the valve, but with both the single and the split valve the "squawk" persisted on the L.P. stroke. If the position, and/or the particular shape of the valve had been the cause of the noise occurring consistently on the L.P. stroke only, then reversing the normal action of the valve, i.e., making the H.P. pressure operate the nominal L.P. section of the valve, and vice-versa, should have changed the "squawk" from the L.P. to the H.P. stroke. This was effected by lowering the whole valve to the level of the transfer passage, see Hs. {Lord Ernest Hives - Chair} 1406E, but this was of no avail, the noise still came on the L.P. stroke. | ||