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).
Proposals to strengthen the 3rd speed coupling teeth on the Silver Phantom gearbox following a failure.
| Identifier | ExFiles\Box 109\1\ scan0161 | |
| Date | 30th August 1939 | |
| 666 BY/NS{Norman Scott} c. Rm.{William Robotham - Chief Engineer} DA.{Bernard Day - Chassis Design}10/N.30.8.39. Silver Phantom etc. - Gearbox. ------------------------------ Herewith is PD.495, shewing the proposals to strengthen the teeth of the 3rd. speed coupling which has failed in France. The number of teeth is reduced, so increasing the thickness, and a further increase is obtained by reducing the relief clearance on the driving teeth, because it is believed that the present clearance is more than is necessary. This will have to be proved. The two drive teeth on the tension side of the cam slot have been removed altogether as they appeared to be a weakness, but those on the compression side have been retained as shewing no disadvantage. The increased strength on the drive teeth is 55% and on the over-run 50%. In both cases the stress is quite low. DA.{Bernard Day - Chassis Design} | ||