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).
Proposed modifications to a silencer and carburettor to improve airflow and reduce noise.
| Identifier | ExFiles\Box 13\3\ 03-page167 | |
| Date | 6th December 1929 guessed | |
| -3- The aforementioned modifications are thought to be the most that can be done to the existing parts, as the air flow is restricted at the air valve ports and the annular spaces between the concentric tubes of the silencer. The following alterations are, therefore, suggested :- (a) Assuming the external diameter of the silencer is now at its maximum desired value, that the centre tube should be omitted and the annular space between each pair of tubes increased, (b) That the centre holes in the end pieces of the silencer (E79577/S) should be increased to suit the larger centre tube (to confirm with (a)). (c) That all the air holes in the concentric tubes should be increased by approx. 50% of their original area. (d) That a standard size air-valve, diaphragm and high speed choke should be employed, and (e) that the spray chamber should be modified to give a greater annular space round the air ports when using a standard suction chamber. Concerning the silence of this carburetter, it shows a considerable improvement on the standard instrument, in that the objectionable hissing noise, associated with the opening of the air valve, is absent. The roaring does not however appear to be much less than with the standard carburetter. The removal of the centre tube (suggested above) does not appear to increase the noise from the carburetter, as far as can be judged on the test-bed. HS{Lord Ernest Hives - Chair}/ACL. | ||