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).
Design and specifications of the 'Myth' front suspension system.
| Identifier | ExFiles\Box 110\3\ scan0042 | |
| Date | 7th December 1940 | |
| Rm{William Robotham - Chief Engineer}/GB - Any comments on this design Rm{William Robotham - Chief Engineer} To Rm.{William Robotham - Chief Engineer} from Ev{Ivan Evernden - coachwork}/DB.{Donald Bastow - Suspensions} C. to Ev.{Ivan Evernden - coachwork} Rm{William Robotham - Chief Engineer}/HH. FRONT SUSPENSION - MYTH PL.423 attached shows the front shockdamper and upper triangle levers of the Myth front suspension. The damper generally is a scaled down version of the latest B.V front damper, using a cast aluminium body, the scaling down being such that the working pressure is maintained approximately the same. During the process of scaling down, a certain simplifications have been made, notably the elimination of the pinch bolt on the internal lever and the method of holding and fitting the replenishment valve spring. The main valves and springs are exactly those of the latest B.V damper shown on PL.106. The upper triangle levers are generally stressed up to approx. 45,000 lb/in2 under a maximum damper load of some 3 times the normal, i.e. 180 lb., and under the rebound and braking loads. This has been done at Rm.{William Robotham - Chief Engineer}'s request with the idea of cutting out all necessary weight, and realising that subsequent stiffening may be necessary after trials. The method of fitting the replenishment valve spring is that each prong is inserted into the groove in turn through the slot in the piston, the final position leaving the fourth prong in the filling slot, so that the spring cannot work out. The connecting links now have their section centrally disposed about the line of the transmitted forces and this is taken as justification for reducing the cross section. On the R.H. lower part of the scheme are plotted the displacement curves. In order to show up the differences at a maximum, the displacements, plotted on a base of angular movement of the damper shaft, have a vertical scale representing piston movement per 5o angular displacement of the damper shaft, the two curves representing the two pistons. The vertical difference between the two curves is thus a measure of the rate at which one piston is moving faster or slower than the other, and it will be seen that the maximum excess of movement of one piston over the other in any given 5o period is only of the order of .0024", in other words about 3% of the maximum piston movement in any one 5o period. This difference is considered small enough to be unimportant. The shockdamper assembly is not handed. Ev{Ivan Evernden - coachwork}/DB.{Donald Bastow - Suspensions} DB{Donald Bastow - Suspensions} | ||