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).
On a Phantom III rear axle coupling failure, proposed modifications, and comparison with Bentley designs.
| Identifier | ExFiles\Box 92\5\ scan0030 | |
| Date | 2nd October 1935 | |
| Rm{William Robotham - Chief Engineer} GRY{Shadwell Grylls} X302 Sg.{Arthur F. Sidgreaves - MD} and Wor.{Arthur Wormald - General Works Manager} from E.{Mr Elliott - Chief Engineer} E.2/HP.2.10.35. c. Hs.{Lord Ernest Hives - Chair} Ey. Da.{Bernard Day - Chassis Design} Phantom 3 Rear Axle. With reference to the failure of the coupling drive to the pinion, as reported in Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}10/KW.1.10.35, it should be realised that we are, and must be, designing for reduction in weight generally in our chassis and its comphents, and that such failures are likely to occur in development. In the case of this coupling it is strange that the taper is one in four instead of our standard, one in six. When a failure of this sort occurs we are not satisfied unless an alteration is made increasing the strength of the job at least 100%. We have instructed an immediate modification altering the taper from one in four as it has been made to one in eight, and increasing the size of the keys, which alteration is applicable to the existing pieces and adds to the strength of the drive by the required 100%. By comparison with the Bentley the shaft and taper diameters should be up to SpectreCodename for Phantom III requirements, and we do not therefore want to increase the shaft bearing and housing diameters unless it is absolutely necessary. We should like to have some experiments made of a similar nature on the Bentley back axle as when we go to the bigger bore engine we want to be assured that it will not precipitate any failures in the transmission. In any case we are checking over the design of this coupling taper which might give trouble. E.{Mr Elliott - Chief Engineer} | ||