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).
Fracture of an 'SS' shock damper shaft, proposing a strengthened design, and questioning component loading.
| Identifier | ExFiles\Box 16\4\ Scan052 | |
| Date | 1st January 1929 | |
| BY.{R.W. Bailey - Chief Engineer} HS.{Lord Ernest Hives - Chair} from DA.{Bernard Day - Chassis Design} X7520 Da{Bernard Day - Chassis Design}2/M.O.1.29. 'SS{S. Smith}' SHOCK DAMPERS. X. 7520 X. 8520 With reference to BY8/G8.1.29, reporting the fracture of a shaft after 6 hrs., we are sending N.sch.2795 herewith shewing how the shaft can be strengthened, not only in the neck where it broke, but under the serrations and all along. We find by calculation however that there is a fair concentration of work at the neck, and in all probability the strengthening at this point will very much increase the life. If the existing shaft is .9" dia, this one is approx. 15% stronger. Would Hs.{Lord Ernest Hives - Chair} tell us whether any shafts on these dampers have lived any considerable length of time. We know there have been fractures of the casing etc., but possibly the same shaft has carried through. As in the case of the casing the strength of this shaft is equal to or more than the similar shaft on the XXXXX Phantom front axle control damper (comparing our own N.sch.) so that it seems certain the ball loads are very much increased. No doubt as soon as possible you will be sending us information about these loads. Presumably you are working with the restrictions in place on the bumping rig, but you do not know the actual figures. We wonder whether you are sure that these evidently very high loads are wanted. It is obvious for instance that you will always be able to break the damper by making the restriction sufficiently great. Is the stiff frame enabling the shock absorber to work, so causing it to break. DA.{Bernard Day - Chassis Design} | ||