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).
Concerns about the weight and performance of car road springs.
| Identifier | ExFiles\Box 43\2\ Scan230 | |
| Date | 14th November 1927 | |
| To BY.{R.W. Bailey - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} c. to Wor.{Arthur Wormald - General Works Manager} Y3900 Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG14.11.27. ROAD SPRINGS. Y3900 X8410 X8540 We are very concerned about the weights of our car road springs. The first test which brought the matter to our notice was that of the American front road springs. These weigh the same as our present front springs, have 16% greater initial deflection and 50% longer life. Therefore proportionately, it appears that the Americans could make a spring to give the same performance as our standard and yet be at least 25% lighter. We understand that the question of design has been taken up with the makers, and that they have particulars of OY's notes on suspension. The next discrepancy which has been brought to our notice is on the rear springs of 14-EX. On this car every effort has been made to save weight and yet we find that the rear springs are almost 10% heavier than the cantilever of equivalent rating i.e. cantilever 356 lbs/1" weight per pair 174.5 lbs. semi-elliptic 180 lbs/1" weight per pair 192 lbs. Now it is clear from the nature of a spring that the same weight of metal should support the same load through the same deflection for the same stress irrespective of whether the spring is a cantilever or a semi-elliptic. We do not know of a single case of rear spring fracture since the contd :- | ||