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).
Results of tests on vehicle wobble, frame twisting, and the effects of engine mass, inertia, and shock dampers.
| Identifier | ExFiles\Box 22\1\ Scan284 | |
| Date | 14th June 1927 guessed | |
| contd :- -2- The amplitude of the wobble was not very great. Reducing the equivalent engine mass increased the amplitude of the wobble appreciably. We also ascertained that if we increased the moment of inertia of the engine mass relative to the crankshaft centre without adding to its mass, we could somewhat reduce the amplitude of the wobble. It should be noted that these results are with the shock dampers at 150 lbs. We have not tried similar tests on the road, although mass added to the front of the car with normal damper loading does not seem to make an appreciable difference to wobbles. We next removed the ballast box from the rear of the frame with somewhat astonishing results. Wobbles of exceptional violence built up, the whole frame twisting about the rear springs. The wobbles were more violent than anything we could get with normal front damper loading, presumably because in this case the frame was moving as a whole and the dampers were for all practical purposes inoperative. We have previously carried out tests comparing the rigidity and periodicity of the Hispano frame with that of EAC.7. To do this we supported the frame in front on a knife edge at the centre of the front cross member, and measured the torsional rigidity for various angles of twist. We also obtained the periodicity for the frame vibrating torsionally. (A) With the rear axle clamped solidly to the frame. (B) With the rear springs free - no damping. The results were :- contd :- | ||