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).
List of modifications for the Wraith III gearbox to overcome faults discovered during testing.
| Identifier | ExFiles\Box 8\11\ 11-page152 | |
| Date | 14th December 1938 | |
| PY/HS.{Lord Ernest Hives - Chair} c. Rm.{William Robotham - Chief Engineer} 628 DA.{Bernard Day - Chassis Design}12/G.14.12.38. WRAITH 111 - GEARBOX. GRY{Shadwell Grylls} Herewith is PD.328 which shews the remaining modifications to the Wraith Gear Box to overcome faults so far discovered in testing :- (1). Increased collar on 3rd Motion Shaft. Required for 'C' Series. A slight machining modification on the 3rd and 4th sliding piece is needed to accommodate the increased collar. (2). Reduced helix angle on 3rd speed gears. Not needed for 'C' series. (3). Increased Tabs on 2nd Motion Shaft, including slight machining modifications to 2nd speed driving piece. Could be got on 'C' series, but not essential. (4). Reduced helix angle on 2nd speed gears. Not required for 'C' series. (5). Increased thickness of gear wheel rims under the teeth, involving also a modification to the 3rd speed outer cone. Not needed for 'C' series. In the case of those modifications 'Not needed for 'C' series", it is intended that they should be got on as soon as possible, but 'C' series instructions need not be modified. [Signature] FJH{Fred J. Hardy - Chief Dev. Engineer} DA.{Bernard Day - Chassis Design} | ||