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).
Performance and design of Myth rear springs.
| Identifier | ExFiles\Box 110\3\ scan0066 | |
| Date | 24th April 1941 | |
| To Hm.{Capt. W. Hallam - Head Repairs} from Rm{William Robotham - Chief Engineer}/GB. Copy to Rm{William Robotham - Chief Engineer}/Clm.{D. D. Clapham} Ev{Ivan Evernden - coachwork}/JD.{J. Draper - Frames} MYTH REAR SPRINGS The four Myth rear springs made by Toledo Woodhead have now been measured. The rate is 20 to 26 lb/inch high. Leaf thickness is -.000 to +.011" and leaf length +.125 to +.57". The shot blasting has been done with broken shot. Leaf radii are not right, resulting in higher stresses in the steel and high pressures on the interleaving. The leaves are not free from heavy hammer marks. Spring friction varies by 24 lb. This would make the damper position impossible. A pair of springs as good as possible will be made from the above samples and put by, for the first Myth chassis. Meanwhile, we must try to get better springs. In view of the possible advantages of the grooved section spring, a visit to Toledo Woodhead's might be worth while. A new spring in flat section steel will be designed, and it is suggested that samples of this be obtained from a number of makers. Careys have supplied springs which were good and which would have been very good, had they not stamped "Tested" on the tension side of the master leaves. The following tables show the leaf thicknesses, lengths and free radii of the above springs. The graphs show the rates of the springs, the effect of the rubber clamp, and the measured suspension rates. | ||