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).
Bump tests on road springs, cam mounting, and a proposed continuous bending test apparatus.
| Identifier | WestWitteringFiles\M\October1924-December1924\ Scan12 | |
| Date | 10th October 1924 | |
| TO HS.{Lord Ernest Hives - Chair} FROM DA.{Bernard Day - Chassis Design} BUMP TEST ON ROAD SPRINGS. X1331 X9410 X2628 Referring to HS{Lord Ernest Hives - Chair}8/LG61024., we infer that the springs tested were not the very latest thin leaf 12 1/2% springs? Presumably you will not as yet have had many of these latter for bumping. It is true that the range of stress in the springs with cam at 0° is rather more than with cams at 180°, but the difference seems hardly sufficient to explain the great alteration in life. It would be interesting if a graph would be prepared shewing the oscillations of the springs in the two methods of mounting the cams. The object of this would be not only to see the amplitude, but also the comparative frequency of the oscillations. One would expect for instance that with the cams at 0° the springs would oscillate a few more times than would be the case with those at 180°, that is to say, the stress is applied more frequently and this might tend to account for the rapid reduction of life. Have you ever considered getting apparatus for testing springs by continuous bending? Since it seems to have been proved that bending is the principal cause of the failure of springs, it would appear that a very quick and efficient method of testing springs would be simply to subject them to rapid oscillations. This aparatus would enable you to vary the amplitude and the number of oscillations per unit time in a way that we think would give us very valuable information. DA.{Bernard Day - Chassis Design} | ||