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 bearing failures, their causes, and the material composition of the bearings.
| Identifier | ExFiles\Box 173\1\ img105 | |
| Date | 20th January 1934 | |
| -4- Certain failures have been experienced on thrust bearings which are arranged at front end of crankcase, being twice the width of Re., longest bearing, and it appears that failures were brought about due to crankcase distortion which owing to length of bearing, would considerably reduce clearance and bring about failure. This trouble was overcome by stiffening of forward end of crankcase, and slightly increasing bearing clearances. I did not see any bearings which had failed, but gathered failures were of an exactly similar nature to those we have experienced. I examined some main bearings out of development engines which had run equivalent tests to R.R. endurance, and could not admit that they were any better than we are accustomed to; after test, main bearings which had run for long periods were in similar condition in every way to Res. (center excepted). The Connecting Rods which are articulated type give no bearing trouble, conditions were exactly like bearings we expect to see after long periods of running, having a beautiful black bloom on surface, being quite different to main bearings which are bright and scratched due to metallic contact. The material structure of lead bronze is close and homogeneous and resembles Kes. Connecting rod bearings which contain 1% Tin, while Wright's are led to believe that bearings supplied is straight 70/30 composition. I doubt it owing to fine material structure and feel certain that tin, zirconium or some other content has been used to prevent segregation and oxidation. Design points of Conqueror will be dealt with in my next report. Re. the complete schedule of type test for both air cooled and liquid cooled engines, which no doubt he will forward in due course. R.H.Coverley. | ||