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).
Outlining the minimum 50,000-mile testing requirements for new vehicle components and chassis designs.
| Identifier | ExFiles\Box 148\2\ scan0091 | |
| Date | 17th December 1938 | |
| - 2 - BY.16/G.17.12.38. In the case of the semi-floating axle, it will be remembered I had insisted on at least 50,000 on individual parts, and that also a number of different chassis must be fitted up and run for similar mileages. I am now convinced that we must make 50,000 miles on individual parts of new designs our minimum requirements, and that this experience must be confirmed by bench tests which will be calibrated with parts which have actually run 50,000 miles on the road. 50,000 miles is selected as representing the period of our three year guarantee, and must therefore be accepted as a minimum requirement and not as giving a wide margin of safety. The margin must be guaranteed by subsidiary bench tests co-related to the road mileage, and carried out so as to ensure a greater durability than the road mileage. The tests must be arranged to cover completely all the road conditions, for instance :- (a). The engine. This must be tested for slow running traffic conditions, as well as full load and also high speed light load testing. (b). The Gear-box. This must be tested on each gear for a mileage (to be determined) which such a gear is likely to encounter in a five years' life. (c). Rear Axle. This must be tested on all gearbox gears. In connection with the 50,000 mile test, it is essential that 3000 miles of this be run in London traffic, to my mind in three sections of 1000 miles each, the first section to be run quite early in the mileage to test out over-oiling susceptibility on a new car. The second section half way through the general mileage, and the final thousand at the end of the 50,000 miles. It is also clear that we must at any cost avoid designing completely new chassis, our reputation was built upon the old 40/50 which was modified little by little and not by drastic redesign. Rm{William Robotham - Chief Engineer}'s rationalised programme has been developed with this object in view, as it cuts right across any attempt to completely redesign any single type of chassis we may be building, as to do so would put all our types in the melting pot, which is of course unthinkable and totally impracticable. | ||