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).
The failure of the Bunsport Car's axle and proposed modifications.
| Identifier | ExFiles\Box 179b\4\ img061 | |
| Date | 13th April 1933 | |
| ORIGINAL. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} C. Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} D.{John DeLooze - Company Secretary} E.{Mr Elliott - Chief Engineer} De. O.{Mr Oldham} Hy.{Tom Haldenby - Plant Engineer} Hdy.{William Hardy} Hs.{Lord Ernest Hives - Chair}3/KT.13.4.33. X4553 BUNSPORT CAR. We have received a report from Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} which shows that the failure of the axle was caused by the breaking of the teeth on the differential bevels on the axle driving shaft. We wired GWH.{George W. Hancock - Head Chateauroux} to try and patch up the axle and come back without the differential because the car has completed all the useful tests it can do in France. The car is now in England and we expect it back at the works today. We have spoken to Da.{Bernard Day - Chassis Design} about the failure and he considers it possible to modify the teeth so we shall have the same margin of strength as on the present 20/25. This is based on us using the modified gearbox for the Bentley, which will have higher ratio gears on the 1st, 2nd. and 3rd. speeds. This gearbox is fitted to the next Bentley car. Another feature which we think will do a lot to save the differential is the fact that we have reduced the weight of the flywheel compared with the Bentley which ran in France. The moment of inertia has been decreased by approx. 30%. We shall of course be able to prove out the strength of any modifications we make to the axle on the road wheel dynamometer. We think that the three modification suggested - i.e. stronger tooth, higher gear ratio, and reduction in flywheel inertia - will overcome this trouble. We are very anxious indeed not to add any more weight than is absolutely essential to this car. Hs.{Lord Ernest Hives - Chair} | ||