Wraith gearbox failure at 35,000 miles and the proposed design modification.
| Identifier | ExFiles\Box 8\11\ 11-page133 | |
| Date | 18th November 1938 | |
| To Hy. {Tom Haldenby - Plant Engineer} .from Rm {William Robotham - Chief Engineer} /Ory. c. Sg. {Arthur F. Sidgreaves - MD} c. Hs. {Lord Ernest Hives - Chair} c. Da. {Bernard Day - Chassis Design} c. RHC. {R. H. Coverley - Production Engineer} c. Hdy. {William Hardy} WRAITH GEARBOX. In order to run the most possible miles on a Wraith gearbox we used the box that did the first 7,000 miles run in France for the second French test, and it has now reached 35,000 miles. At this mileage the first motion shaft has broken. A design has been prepared eliminating the under-cut where the fracture occurred of a shaft in S/ZNCR instead of S/ZNX which will go in the existing space. We believe that this modification will provide sufficient strength to prevent the possibility of failure. A dynamometer run has been started to prove this point. Meanwhile we have asked the works not to fit any more of the present shafts but to change to the new design. Rm {William Robotham - Chief Engineer} /Ory. | ||
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).