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).
Suggestion regarding the material for timing gears on the New Wraith engine unit.
| Identifier | ExFiles\Box 136\1\ scan0201 | |
| Date | 3rd February 1937 | |
| 1155 1044 E.{Mr Elliott - Chief Engineer} from Rm.{William Robotham - Chief Engineer} c. to Hs.{Lord Ernest Hives - Chair} Rm{William Robotham - Chief Engineer}8/R.3.2.37. TIMING GEARS - NEW WRAITH ENGINE UNIT. It appears to us that the two metal gears in the train of timing gears on the new Wraith engine unit form an ideal subject for trying out the gear steel used by Fords, etc., which is tempered throughout to give a hardness of 450 Brinnel, thereby avoiding distortion. The tooth loading on these gears must be exceedingly low, particularly as they are relieved from crankshaft movement by the spring drive. We suggest that gears should be instructed in this material from the start, and that grinding should only be resorted to if it is found necessary. Rm.{William Robotham - Chief Engineer} | ||