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).
Causes and potential solutions for high and low-speed steering wobbles and road shocks.
| Identifier | ExFiles\Box 28\4\ Scan287 | |
| Date | 7th August 1925 | |
| To Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to CJ. BY.{R.W. Bailey - Chief Engineer} c. to PN.{Mr Northey} BY.{R.W. Bailey - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} 457 R4/M.7.8.25. HIGH AND LOW SPEED STEERING WOBBLES AND ROAD SHOCKS.. X.457 X.8520 We have come to the following conclusion which we would like you to prove - (1) That high speed steering wobbles are affected by the tyre pressure and the amount of castoring of the steering pivots. These two items seem to affect the vigour and the speed at which the steering wobbles occur. (2) That out of balance is the surest way of starting these wobbles, but that they can be started by suitable shocks from rough roads, or by sudden handling of the car. It is impossible for us to control the tyre pressure and the lean of the pivots have been settled for reasons well understood so that we cannot alter the latter unless we introduce some other method of front axle control which would prevent a variation in the pivot lean, and therefore enable us to work with a finer angle, but at the moment we fear this is not practicable - if ever. So that with the existing and unavoidable conditions which we have to face we are forced to rely entirely upon some form of damping friction. We are expecting that with every tyre pressure, and other conditions being normal, a different amount of friction will be needed to prevent the wobbles building up alarmingly. We understand you are now ascertaining what friction is needed. If our pendulum lever is not found to give sufficient friction, and if it is found that the plain thrust friction on the pivots is unreliable, it would seem that we are faced with the only alternative of providing dampers in one or two other forms. If the mechanical friction required for safety produces a steering which is too heavy to be handled without fatigue, even if lower geared, then it is only possible we think to use the fluid damper, which should not affect slow moving necessary for steering. We believe that this fluid damper will be found to be wonderfully good, and are anxious to get contd :- | ||