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 failures of the rear springs and support bracket during a 48-hour bump test of the Goshawk 11 chassis.
| Identifier | ExFiles\Box 49\3\ Scan066 | |
| Date | 15th November 1921 | |
| To R. {Sir Henry Royce} from hs. {Lord Ernest Hives - Chair} c. to CJ. c. to E. {Mr Elliott - Chief Engineer} c. to Da. {Bernard Day - Chassis Design} c. to BY. {R.W. Bailey - Chief Engineer} c. to EP. {G. Eric Platford - Chief Quality Engineer} c. to Wor. {Arthur Wormald - General Works Manager} X4261 Hs {Lord Ernest Hives - Chair} 2/LG15.11.21. GOSHAWK 11. BUMP TEST. X.4219 X4268 X.1202 X4261 We have now bumped the rear of the Goshawk chassis for 48 hours. During that time we have had the following failures. Top leaf rear spring broken after 15 1/2 hours. " " " " " 19 1/2 hours. " " " " " 23 1/2 hours. Front support bracket for rear spring O.S. after 48 hours. We are sending samples of the broken pieces to R. {Sir Henry Royce} As regards the broken spring bracket, this is another case where the fracture has occurred close up to the brazing. Experience so far with brazing on Goshawk 11. has not been very successful on parts which are highly stressed. As regards the failures of the top leaf of the rear springs. We think that if this happened on the road it might be very serious because as the rear springs act at radius rods, if one of these broke, the rear axle would steer the car off the road. We recommend we look into the question of whether it is possible to fit a stop on the shackle similar to what we use on the front spring in order to avoid excessive movement of the axle in case of a spring failure. The failures of the springs have all occurred where the clip is placed. We are running the springs now with this clip removed to see whether it will make any difference. hs. {Lord Ernest Hives - Chair} | ||