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).
Rating tests and interchangeability for full and moderate supercharged 'H' engines.
| Identifier | WestWitteringFiles\V\December1930-February1931\ Scan024 | |
| Date | 15th December 1930 | |
| To R.{Sir Henry Royce} c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} Rg.{Mr Rowledge} c. to E.{Mr Elliott - Chief Engineer} By.{R.W. Bailey - Chief Engineer} c. to Mr. Jaques. A.I.D. X4453. Hs{Lord Ernest Hives - Chair}/RHD.1/MB.15.12.30. FULL AND MODERATE SUPERCHARGED "H" ENGINES RATING TESTS AND INTERCHANGEABILITY. We have been requested by the Air Ministry to produce a full supercharged "H" engine giving 750 BHP.at 2000 R.P.M. at an altitude of 9,000 ft. or so. It was also pointed out at the time that the type of engine preferred would be such that a change from full to moderate supercharge could be effected by a change in supercharger gear ratio only. Tests have been done to develop two engines on these lines. We have incorporated in both engines our latest developments in camshafts to reduce detonation. That is, both engines have been tested with "F" engine camshafts. By doing this we find we have a full supercharged "H" engine with proportionately equal performance to the full S/C. and a moderate S/C. engine with a better performance than our existing engine. Our tests have included full and moderate supercharged engines having 10.25" diameter rotor and 9.5" diameter rotor, the full supercharged engines having 9.5/1 gears with 9.5" rotor and 8.3/1 and 8.9/1 gears with 10.25" diameter rotor. Previous tests on the 9.5" rotor and 9.5/1 gears showed a good performance and consequently tests were carried out with a moderate engine using 9.5" rotor so that the question of interchangeability could be discussed when considering the performance of the two types. A summary of our results is given in the following table:- contd. | ||