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 use of longer rear springs on the Wraith replacement chassis for improved performance and cost-effectiveness.
| Identifier | ExFiles\Box 9\5\ 05-page213 | |
| Date | 19th May 1938 | |
| 646 c. Rm.{William Robotham - Chief Engineer} DA.{Bernard Day - Chassis Design}15/G.19.5.38. REAR SPRINGS. I see the Wraith replacement chassis is going forward with 50" rear springs. I suggest that it is wrong to perpetuate this length of spring, and it would be better to make 56" springs or even longer in Wraith, and apply them to all cars when possible. The tilting effect on the rear axle due to engine torque and braking is inversely proportional to the square of the length, for the same rating of spring. I suggest that the long spring is lighter and cheaper than the short one. Lighter because there is always redundant metal in a plate - the dead part between the centre clips and at the ends - and the fewer plates the less redundant metal; and cheaper because it seems certain it will be cheaper to make few thick plates than many thin ones, though the weight of steel is the same. Generally, one would think it was better to make the rear springs as long as practicable. DA.{Bernard Day - Chassis Design} [Handwritten in blue ink over the first paragraph: Rm{William Robotham - Chief Engineer}] | ||