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).
Power loss tests conducted on resonance air silencers for a Phantom II semi-expanding carburettor.
| Identifier | ExFiles\Box 13\4\ 04-page056 | |
| Date | 25th November 1932 | |
| X7080. 25.11.32. POWER LOSS TO RESONANCE AIR SILENCERS. P.II SEMI-EXPANDING CARBURETTER. Unit P.II. 25. Comp. Ratio 5.25:1 Camshaft E.62443 (1149) Three silencers have been tested for power loss in conjunction with silence tests carried out by Whyman. Particulars of these silencers are given in a report by Whyman of 3.11.32. (a) Largest size. no B.H.P. loss. (b) Intermediate size:- max. loss 0.5 BHP. at 3300 RPM. (c) Smallest size :- " " 3.0 BHP. at 3300 RPM. --------- Referring to a later report of 22.11.32., the latest silencer consists of two timing chambers situated one above the other on a vertical intake pipe. This has been tested with three sizes of intake tube, and power losses are as follows. 2.875" dia. pipe - no power drop. 2.687" " " - max. loss 1.3 BHP. at 3300 R.P.M. 2.562" " " - max. loss 2.7 BHP. at 3300 R.P.M. --------- Summarising these tests we find that the roar can be effectively silenced with no loss of power; and can be eliminated with a loss of 1.94%. C.T. Salt. | ||