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).
Type test report on increasing the RPM of M.S. 'F' engines, detailing fuel consumption and power figures.
| Identifier | ExFiles\Box 36\2\ scan 214 | |
| Date | 11th May 1929 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/VH. c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c; to BY.{R.W. Bailey - Chief Engineer} 42934 Hs{Lord Ernest Hives - Chair}/VH1/LG11.5.29. M.S. 'F' ENGINES. 2400 r.p.m. Type Test with 5.5/1 pistons. Having decided to raise the normal r.p.m. of our M.S. 'F' engines from 2250 r.p.m. to 2400 r.p.m. so that the rating of these engines may still be 525 B.HP. at 4000 ft., we have completed a series of fuel consumption and power curves - appended herewith. Braking the engine down from 525 B.HP. at 2400 r.p.m. - i.e. taking a 'gate' power curve - we find that no detonation occurs until as low as 1700 r.p.m., when very slight detonations can be heard. We find that the weakest maintained fuel consumptions are better at 2400 r.p.m. than 2250. This applies in both the 525 B.HP. figures and 472 B.HP. figures. Consumptions are : R.P.M. B.HP. Pts/B.HP/hr. Weakest 2250 472 .537 maintained 2400 472 .532 figures 2250 525 .537 (dropping 2 2400 525 .517 lbs. on brake) The full strong consumption is rather high, but this can be easily remedied by weaker initial jet setting. These figures were taken with the carb. tuned for 2250 r.p.m. The 2400 r.p.m. setting will be determined later. contd :- | ||