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).
Half shaft spline failures and design variations from E.R.A.
| Identifier | ExFiles\Box 114\1\ scan0116 | |
| Date | 16th December 1937 | |
| To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} c. Da.{Bernard Day - Chassis Design} c. Hdy.{William Hardy} 1015 Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}1/AP.16.12.37. HALF SHAFT SPLINES. We think the following information from E.R.A's is of interest. E.R.A. were in such trouble due to spline failure that they rang us up to ask what material to use. Their shaft was then shaped as No.1. in the sketch and would just last a 500 kilometre race. They therefore tried type 2, which broke at A.{Mr Adams} in about the same length of time. This is the type of spline to be used on M.{Mr Moon / Mr Moore} series but in addition we have put up the shaft diameter. Since then they have used the third scheme in which the top diameter of the splines tapers back for 3" to the normal shaft diameter and have not yet had a failure. The E.R.A. failures are torsional failures occurring at the inside end of the shaft where it enters the differential. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} | ||