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).
Conclusions from tests investigating air flow and pressure differentials for inlet ports, induction ports, and combustion chambers.
| Identifier | ExFiles\Box 17\6\ Scan158 | |
| Date | 25th September 1933 | |
| -2- He/Std.6/KT.25.9.33. (c) To investigate point (4) - air flow/press. diff. curves were taken for two inlet ports of a non-turbulent Phantom I head - see sheet 2 - average of the two ports taken. A standard inlet valve E.82458 was fitted to a large valve P.II. head - R.83906 - by means of a special seating (in this way the trepanning effect of the standard head was increased) and air flow/press. diff. curve was taken - see sheet 3. CONCLUSIONS FROM TESTS. Length of Induction Port. From sheet 4, it is seen that out of a pressure head of 26" of water (across entrance to port and outlet from combustion chamber) at least 5" of pressure head is lost between entrance to port and valve seating (at the top speed flows). Hence a material gain could be expected by shortening the port as far as possible - the Bentley port is approximately 6.5" long against the R.R. length of 3.5" - 4.0". Shape and Curvature of Induction Port. From sheet 1, it is seen that the centrifugal action of the air due to curvature of port has no appreciable effect - the angle of the port to centre line of combustion chamber (in plan) is not important. Design of Combustion Chamber. From curves on sheet 2, by comparing the Phantom I head (non turbulent) (valve size 1.72" dia) with the Phantom II head (turbulent) (valve size 1.70" dia) it is seen that there is a small gain obtained with the non-turbulent head, however, as seen in a previous part of this report, this gain would not be reproduced proportionately if a non-turbulent large valve head were used. It would probably not outweigh the loss in power due to the lower compression ratio necessitated by the non-turbulent type of head. From sheet 3, it is seen that the increase in trepanning gives practically no improvement. Number of Valves per Cylinder. It has not been possible to compare a "two inlet | ||