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).
Performance of tulip-shaped valves versus conical-faced valves and outlining future testing plans.
| Identifier | WestWitteringFiles\K\June1923\ Scan13 | |
| Date | 19th June 1923 | |
| ORIGINAL TO RG.{Mr Rowledge} & HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} R4/M19.6.23. c. to C.J. OV c. to HH. EP{G. Eric Platford - Chief Quality Engineer} X 3616 We have been using in our valve practice a combination of a tulip shaped valve with a nearly flat face (15°). We have come to the conclusion that this is not an improvement, that the valve face ought to be conical to at least 30° possibly 45° to facilitate it's seating correctly. Also in the case of the exhaust valve the direction of the stream of hot gases would be directed away from the stem and head of the valve. It is thought that the tulip shape has a tendency to heat owing to the hot gases infringing upon the surface of the tulip head which remains in the passage when the valve commences to open. These observations are partly our own, and partly derived from the information given to us by Col. Fell. I shall be glad if Mr. Rowledge will make and Mr. Hives test a number of patterns of various angles of valves and various shapes of head, from 45° conical face to 22½° conical face, and from the tulip to the umbrella type, bearing in mind that we cannot believe the tulip shape is suitable for the flat valve face, and we think also that it is not necessary to have the umbrella head with a conical valve face. The relative virtues of each we want to test, for which reason it may be advisable to use regular but rather poor material. Also a bad shaped valve might be a good one to test materials for the best material. Since writing the above, Mr. Hives has brought samples of valves from the Works shewing the above is extremely urgent, and parallel with the experimental work and proving test we ought to standardise a return to our older practice of:- (1) Increased angle of face. (2) Increased area of face. (3) Less tulip shape. R.{Sir Henry Royce} | ||