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).
Page 2 of a report analysing engine efficiency, chromium plated bores, and losses in silencer and induction systems.
| Identifier | ExFiles\Box 133\1\ scan0201 | |
| Date | 13th May 1937 | |
| -2- R.P.M. 1000 1500 2000 2500 3000 3500 4000 4250 4500 3½ litre. 88.2% 86.5% 84% 81.2% 78.1% 74.5% 70.5% 68.1% 65.4% 4¼ litre. 88% 86.0% 83.6% 80.8% 77.2% 73% 67.8% 64.0% 59.5% A fall off in efficiency for the large unit will be observed at speeds over 3000 R.P.M., this drop being in the region of 6% at 4,500. CHROMIUM PLATED BORES. Fig.III. shows a comparison between chromium plated bores and standard bores, giving a slight gain for the plated job. SECTION II - ANALYSIS OF LOSSES (Figs.VII. to XI.) It is proposed to deal with the losses of each component part separately, and in all cases figures will be given in Lost Horse Power (L.H.P) (1) Silencer System. A normal test bed silencer system was used in each case, and losses appear to be about equal. As this item is relatively unimportant, it will not be enlarged upon. (2) Induction system losses. It must be borne in mind when dealing with these losses that the item considered here is the actual air friction loss in the carburetters and induction pipe and whilst this loss has a considerable bearing on the air flow and volumetric efficiency of the engine, is in itself, a relatively small factor. However, due to its effect on power output, it is considered in some detail, and comparative figures are as under:- R.P.M. 500 1000 1500 2000 2500 3000 3500 4000 4250 4500 3½ litre. - .325 .530 .850 1.235 1.700 2.280 2.940 3.30 3.69 4¼ litre. - .082 .147 .230 .328 .590 .802 1.118 1.395 1.62 continued | ||