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).
Experiments with port and valve shape designs using wooden models.
| Identifier | ExFiles\Box 17\6\ Scan141 | |
| Date | 24th August 1933 | |
| -7- Hs{Lord Ernest Hives - Chair}/Std.11/NA.{Mr Nadin} 24.8.33. Port & Valve shape design etc. Two special wooden models of experimental heads were tried (Hs.{Lord Ernest Hives - Chair}1045 & Lec.3571) - curves are shown on Curve 10, compared with standard head. These curves indicate a definite increase in air flow but how far this small improvement would be reproduced actually on engine is difficult to predict owing to difference of surfaces ports etc., in wooden models from actual head. Note:- The first head - Hs.{Lord Ernest Hives - Chair}1045 had a valve and seating shaped so that the opening was a venturi passage through out the whole of its lift. The second head Lec.3571 had an increased area of port and the port was displaced relative to the valve so that the more effective half tended to be used more than the other half. Differences between individual ports of the same head. The curves on curve 7 show the variation of flow on different ports of the same head, and indicate the limits of experimental error when compared different heads. The differences may be due to slight casting differences of the ports or may be due to experimental error - without having machined ports it is impossible to separate these differences. Experimental Value of these Results:- It must be mentioned in connection with these tests that air is a somewhat unreliable medium to work with, that the blower used was by no means the most suitable, and that a certain amount of inexplicable inconsistency was obtained - in general however, the results were definitely reliable if carried out carefully. | ||