Delaying the specification for Hall's metal big end bearings for the Wraith III, pending endurance testing of a new A.C.9 alloy.
| Identifier | ExFiles\Box 115\3\ scan0218 | |
| Date | 22th April 1938 | |
| SECRET To By. {R.W. Bailey - Chief Engineer} from Rm {William Robotham - Chief Engineer} /Swdl. {Len H. Swindell} c. RHC. {R. H. Coverley - Production Engineer} c. Ha/JHW. c. RHC {R. H. Coverley - Production Engineer} /SS. {S. Smith} 1020. Rm {William Robotham - Chief Engineer} /Swdl. {Len H. Swindell} 1/AP.22.4.38. BIG END BEARINGS (WRAITH III.) We have held up the specification for the Hall's metal big end material pending an endurance run on A.C.9. material both in centri-cast form and die-cast to size. This material was evolved for ease of casting with less scrap than experienced with the other alloys previously used, namely A.C.6. and A.C.7.; we do not wish to release for A.C.6. material when there is every possibility of the A.C.9. proving to be a satisfactory bearing material in a short time, we hope to have results in a fortnight. In the meantime, however, if any units are held up for big-end bearings we recommend that they be fitted with original A.C.6. material produced from the billet until such time that the A.C.9. material is proved and released. Rm {William Robotham - Chief Engineer} /Swdl. {Len H. Swindell} | ||
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).