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 effects of dampers, friction, and engine mounts on steering wobble and wheel fight.
Identifier | ExFiles\Box 170\3\ img057 | |
Date | 20th June 1935 | |
-4- Using this damper on the road a "best" setting was found at which the wobble tendency seems to disappear. Considerable friction is found desirable and gives distinctly better results than frictionless setting. Too much friction causes increased wobble. This damper is not a suitable type because of increasing engine noise in the car. The friction should be applied at the intermediate support. (probably on one side only) to avoid telephoning the noise. Possibly front and intermediate mounts of increased softness using rubber in shear to get increase damping action would result in complete control of wobble without the complication of adjustable friction dampers. CONCLUSIONS: 1. Rotary frequency of engine mount is of vital importance in the control of wobble and wheel fight. 2. The best setting appears to be to set the engine frequency somewhat below the wobble frequency. 3. The damping of the mount then becomes important and requires adjusting by trial. Question: Can inland control the internal damping of a rubber engine mount without changing its stiffness? Unless the damping is adequate, the "float" of the engine on such a soft mount becomes objectionable. With adequate damping the float is scarcely perceptible. 4. When engine mount conditions are right, a wobble which will "build up" can be prevented even with practically frictionless steering gear and kingpin. However, we doubt whether a frictionless steering can ever be made to feel as steady on the road under all conditions as one in which some damping is applied either at the kingpins (by plain bushings) or in the tie rods. M.{Mr Moon / Mr Moore} Olley, June, 20, 1935. | ||