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).
Peregrine development engine tests, focusing on crankshaft balancing and main bearing performance.
| Identifier | ExFiles\Box 115\2\ scan0376 | |
| Date | 10th January 1939 guessed | |
| - 2 - K.3377 was run for 50 hours on Peregrine rating for a fuel economy test, at the end of this the bearings were bad but this was thought to be due to the soft shaft. This shaft was balanced and the conclusion was drawn that the hard shaft unbalanced was better than the soft shaft balanced. The results of these tests indicated that balancing was necessary to save the centre main bearing panel and bearing and that wear was considerably reduced by using a VCM nitrided shaft. This was accordingly recommended for the original Peregrine design. EXPERIENCE ON PEREGRINE DEVELOPMENT ENGINES. (a) Peregrine I. 1. This engine went through type test at normal rating with a hard balanced crankshaft, at the end of this No.1 and 7 main bearings had metal broken away on the sides nearest No.4 owing to heavy bedding (see photo KP.15). The effect was also showing on Nos. 2 and 6 on the sides away from No.4. The end main bearings were modified with a 0.0066" taper per inch for the last half inch towards No.4 main bearing, the relief afforded did not effect a cure as after a further 40 hours thrust test the same trouble was evident. Peregrine II. 2. Reverse rotation engine, this went through type test and the bearings were satisfactory after 165 hours running except that No.7 had been replaced after 34 hours running and had only done 131 hours in the type test and none of the preliminary running. Peregrine I. 5. No.7 main bearing was rejected after 73 hours running which included about 40 hours airscrew tests. The bearing had metal broken away at the front of the lower half in the same way as previous bearings which had failed. The above tests all showed that the balancing had had an adverse effect on the end main bearings and so on Peregrine I No.3 a VCM unbalanced shaft was tried after the engine had done | ||