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).
Fatigue tests of proposed stiffer axle shafts for the Phantom III, recommending their production.
| Identifier | ExFiles\Box 92\5\ scan0114 | |
| Date | 19th April 1937 | |
| To Hs.{Lord Ernest Hives - Chair} c. to Sg.{Arthur F. Sidgreaves - MD} c. to Da.{Bernard Day - Chassis Design} c. to Sy. 302 Rm{William Robotham - Chief Engineer}/Smth.3/JH.19.4.37. Phantom III Stiff Axle Shafts - N.Sch.4982. We have now completed a series of fatigue tests on the proposed stiffer axle shafts, and find them to be considerably stronger than the present standard ones. All the shafts broke either in the spline portion, or close to it. Detailed results are appended, and also a photograph showing typical fractures. In every case the fracture consists of longitudinal cracks running radially inwards from the roots of the splines. It appears that for fatigue loading it gives a stronger construction to make the shaft diameter that of the top of the splines rather than the root. There are longitudinal cracks running from the root of every spline in the flexible shafts, but not in the stiff ones. We now have four sets of stiffer shafts running in experimental cars, and will shortly have two more. 35-EX in France has run over 3,000 miles since the shafts were fitted. In every case the shafts have improved the transmission and clutch engagement, and we suggest that we should now put them into production. The extra cost will be about 4/- per car. Rm{William Robotham - Chief Engineer}/Smth. | ||