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).
Engine safety tests, including performance data, backfiring issues, and cylinder testing.
| Identifier | ExFiles\Box 179\2\ img189 | |
| Date | 27th January 1932 | |
| -2- Rs{Sir Henry Royce's Secretary}/Yng.1/W.27.1.32. Cont'd Nominal R.P.M. (Normal) Rated Altitude Nominal BHP. at Rated Alt. (O.L.) Power. Air 6101. AP.840. French Rating. 2500 11,500 460 515 530 English " 2250 11,500 428 --- 480 Safety Test. (Section 7 of Schedule Air 6105) With regard to paragraph (a). The inlet valves of A.1 cylinder were set open .080" and the engine run with this cylinder shorted. The brake was then set to give nominal power (460 BHP) at nominal R.P.M. (2500). The engine was now throttled back on this brake setting to tick over RPM. and A.1 cylinder cut in. No difference in running was observed. The engine was then slowly opened up. At approx. 1400 R.P.M. backfiring occurred and the engine stopped. Several further attempts were made but on each occasion backfiring occurred at 1400 R.P.M. Test (a) was therefore washed out. A Kestrel engine will not run under these conditions. Test (b) was then attempted. The tappets were reset to normal. Several runs were made crossing a different pair of wires each time. The engine would run on both magnetos but on every occasion when the magneto having the correct wiring was earthed, the engine backfired and stopped. Test (b) was therefore washed out. It should be pointed out at this juncture that as soon as a backfire occurs on our type of boosted engine (i.e. with m/c. between the carburetter and cyls.) that the engine stops immediately due to the whole of the mixture having been burnt in the induction system. If, however, the throttle is rapidly closed the engine can be 'caught' and kept running. Test C.1 was carried out by running up to nominal power at Nominal R.P.M. with a pressure equal to atmospheric at 11,500 ft. in the air intakes. The engine was then weakened off on the A/C. until it cut out. Five mins. was spent on this but heavy back-fires did not result under these conditions. For Test C.2 the H.T. wires of the exhaust spark plugs of cylinders B.1 and 2 were crossed. The engine was | ||