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).
Report analysing different exhaust system configurations and their effect on reducing engine boom noise.
| Identifier | Morton\M13.2\ img003 | |
| Date | 8th December 1930 | |
| -2- Hs{Lord Ernest Hives - Chair}/GR.{George Ratcliffe}2/AL.8.12.30.Contd. The effect of temperature on the boom is therefore not due to restraint of expansion of the exhaust system as a whole. Analysing the exhaust system we find that - (1) The combination of an expansion box in the down-take pipe and a Vortex "A" silencer cures all except the high speed boom, this latter being decreased in amplitude. (2) A standard down-take pipe and Vortex silencer is not quite so good on the high speed boom, the others still being absent. (3) The expansion box in combination with standard R.R. silencer was not as good as experiment (2). The 2350 R.P.M. (50 M.P.H.) boom was present to a small extent Both (2) and (3) however, were a distinct improvement on standard. These tests require confirmation on the road also with a 'China' engine. Hs{Lord Ernest Hives - Chair}/H.Grylls. | ||