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).
Letter to Dr. J.C. Morrison of Glasgow University seeking advice on reducing power loss in engine silencing systems.
| Identifier | ExFiles\Box 133\1\ scan0231 | |
| Date | 17th June 1937 | |
| 1129 Rm{William Robotham - Chief Engineer}/Edll/R.{Sir Henry Royce} 17th June, 1937. Dr. J.C. Morrison, The University, G L A S G O W. Dear Dr. Morrison, It has recently fallen to me to do the job of power loss in silencing systems, and to see if any way can be found of reducing this loss without adversely affecting the silence of the system. We have facilities here for three systems of testing, viz. single cylinder units, main engines on the bed and actual road testing, and it is desired to run tests on the single cylinder unit which will line up with full scale tests on the bed and on the road, the idea of course being that it is cheaper to test a single cylinder unit than a main engine with six or twelve cylinders. Now in 1933, I see you wrote a paper on this job, which so far I must admit I don't quite understand, so instead of asking questions about this which would probably not be very bright, I would like to know whether you can give me any idea of the following:- (1) Effect of valve and port shape and size. (2) Are two exhaust valves better than one for silence ? (3) What effect has valve timing on silence ? Would you expect a valve timing giving optimum power open exhaust to continue to give best results when a silencer was fitted to the engine ? (4) We find during tests, that as the exhaust pipe temperature rises, so the back pressure rises. Can you explain this phenomenon ? | ||