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 causes of front axle wobble and the application of damping devices to prevent it.
| Identifier | ExFiles\Box 29\1\ Scan011 | |
| Date | 12th June 1925 | |
| R.R. 499A (50 H) (D.D. 31. 12-6-25) J.H.D. EXPERIMENTAL REPORT. -3- Expl. No. REF. Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG39.25. elements previously mentioned. It should be pointed out that a front axle will not start to vibrate in a criss cross manner xxxxx unless some periodic impressed force acts upon it. Unfortunately all periodic impressed forces acting on the axle are not under our control. They include :- (a) Static out of balance of a wheel. (b) Dynamic " " " " " " " (c) Periodic road shocks due to wavy road surface. Item (a) can be eliminated. (b) is difficult to deal with but we do not know its true significance at the moment. Item (c) is entirely outside the control of the designer. Therefore the position we have arrived at on this side of the question is that the design difficulties of preventing the front axle being susceptible to wobbles are very great, and that it is impossible to eliminate entirely the forces which excite the wobble in its initial stages. Tests (b). These have resolved themselves almost exclusively into the application of damping devices to discourage a wobble from starting and further to prevent it building up when it has started. The two main methods of damping are :- (a) Frictional resistance. (b) Hydraulic resistance. The former has the advantage of reliability and simplicity. The latter in that greater damping can be applied to a rapid motion than to a slow motion. Thus normal motions will not be affected to such an extent as violent oscillations occurring during contd:- axle | ||