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).
Addition to a report on tests for the efficiency of valving of Phantom II & Bentley engines, comparing wooden models to machined castings.
| Identifier | ExFiles\Box 31\2\ Scan140 | |
| Date | 6th December 1933 | |
| FILES. V1497. 6.12.33. X219 X21-1 FURTHER ADDITION TO REPORT ON TESTS ON EFFICIENCY OF VALVING OF P.II & BENTLEY ENGINES. (Hs{Lord Ernest Hives - Chair}/Std.11/MA.24.8.33). Since making the above report attempts have been made to analyse the reason for the differences in flow between the wooden model and actual machined casting of a given design. An account of the tests and the results obtained are attached. The possible causes of the above mentioned differences are :- (1) Errors in manufacture of model or casting. (2) Differences in radii and streamlining of model and casting - in general the radii in the wooden model are better rounded and finished. (3) Difference in smoothness of surface of port TESTS CARRIED OUT. The heads available for experiment were a wooden model of a standard head(1.4" dia valves) and an alum. section of a head to EB.1237, the latter having a very shallow combustion chamber (7.5/1 c.r.) This latter head differs from standard in having large dia. inlet valves(1.5") and the inlet port displaced relative to the inlet valve as in Hs.{Lord Ernest Hives - Chair} , this latter feature having been shown to reduce the volumetric effy. of the head slightly. TESTS. (1) Air flow/press.diff. curve for EB.1237 head. (2) " " " " " EB.1237 head, the head having had the port streamlined (by the use of plastic wood) and polished and enamelled to give it a good surface. (3) Air flow/pres.diff. curve for standard wooden model. (4) Air flow/pres.diff. curve for EB.1237 - head as (2) but with turbulent portion around inlet valve machined away. | ||