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 method and calculations for springing sports cars with 25% stiffer springs.
| Identifier | ExFiles\Box 65a\1\ scan0118 | |
| Date | 30th September 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 Hm.{Capt. W. Hallam - Head Repairs} c. to Mx.{John H Maddocks - Chief Proving Officer} Y8779 Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}3/LG30.9.27. METHOD OF SPRINGING SPORTS CARS. X8410 These cars to be sprung with 25% stiffer springs. (1) Definition of a 25% stiffer spring. A spring requiring 25% more load to produce a given deflection than a standard spring i.e. rating of standard spring 300 lbs., 25% stiffer rating 375 lbs. (2) Buffer clearance. With a normal spring a given load is required to be added to deflect the spring from the normal load position to the buffer i.e. 4.125". With a 25% stiffer spring the same load will only deflect the spring through 4.125 X 100 / 125 = 3.3" Therefore with a 25% stiffer spring the same immunity from hitting the buffers will be obtained with 3.3" buffer clear-ance or with our present arrangement 1.92 neg. camber normal load. (3) Normal deflection. The normal deflection of the spring will not be 8" as standard but 8" X 100 / 125 = 6.4". Therefore in order to give 1.92 neg. camber under a deflection of 6.4" the free camber will have to be - (4) Free or Initial camber. This will be 3.2 - 1.92" or 1.28" positive. (5) Reduced buffer. As cars likely to be sprung like this will require more than ordinary immunity from hitting the buffers the depth of the buffer with these springs should be reduced by .5". contd :- | ||