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).
Comparative power tests of standard vs. long duration cams on the F.XI.S. engine no. 35.
| Identifier | ExFiles\Box 43\3\ Scan193 | |
| Date | 21th September 1928 | |
| COPY. Lr{Mr Ellor}13/LG21.9.28. COMPARATIVE POWERS OBTAINED WITH STANDARD AND LONG DURATION CAMS FROM TESTS CARRIED OUT ON THE RR.F.XI.S. ENGINE NO.35 (VICKERS). Further tests have been carried out on the altitude supercharged engine supplied to Vickers with a view to:- (1) Increasing the power available. (2) Satisfying the representatives of Messrs. Vickers that the actual B.HP. available with the standard camshafts was greater than their computed power derived from the aircraft performance analysis. The results of the tests are plotted in graph form on the accompanying sheets of curves. On Sheet 1. the test bed figures are plotted corrected to a constant box temperature of 15°C. Air boxes were being fitted and the main throttles fully open, the inlet pressures being reduced from ground level to an equivalent pressure height of 15,000 ft. Two speeds were investigated i.e. 2250 r.p.m. (normal) and 2500 r.p.m. The sequence of tests was as follows :- (1) Acceptance tests prior to delivery of engine (21.5.28) These comprise a short range of box tests covering equivalent pressure height from 9000 to 12,000 ft. - see chain-dotted line on Sheet 1. Also a constant throttle curve under ground level conditions at + 25" Hg. boost - see chain-dotted line Sheet 2. Under these conditions a series of flight tests were conducted and the engine performance predicted from the aerodynamic analysis. These figures were considerably less than our predicted figures. contd :- | ||