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).
Technical memo regarding failures of the Phantom III gearbox 2nd motion shaft and a proposed strengthened design.
| Identifier | ExFiles\Box 94\2\ scan0119 | |
| Date | 14th December 1936 | |
| 328 GRY{Shadwell Grylls}/Z PT. C. B. Da.{Bernard Day - Chassis Design} Rm.{William Robotham - Chief Engineer} FHS/HPS.{Horace Percy Smith - Experimental Factory Mgr} E/HDY.{William Hardy}1/HP.14.12.36. Phantom III Gearbox. We send herewith N.Sch.4969 showing a strengthened rear end for the 2nd motion shaft which has recently been shown to be necessary by dynamometer testing. In two cases the threaded ends of the shafts have broken off, and in other cases the nuts have worked loose. The cause of the trouble appears to be the concentration of load on one side of the nut due to the rocking of the gear under the end thrust of the teeth. This travels round the nut as the shaft rotates and thus fatigues the shaft. It also seems that the left-hand thread is not of any value in this particular case, and should, therefore, be made right-hand. The roller bearing is located sideways with slight clearance between hardened washers. E/HDY.{William Hardy} N.Sch.4969 herewith. | ||