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).
Analysis of steering instability, self-centering, and the effects of braking on front axle and spring dynamics.
| Identifier | ExFiles\Box 178\1\ img125 | |
| Date | 13th July 1926 guessed | |
| - 26 - Even with a normal front spring the leaves are twisted into a position something like this. Now it is clear that when the axle is tilted forward the pivot is also tilted forward. We have previously shewn that when the pivots are tilted backwards the steering self-centres. Conversely, it can be demonstrated practically that when the pivots are tilted forward the steering tends to run over on a lock once it is moved out of the straight, in other words, it is in a position of unstable equilibrium. The significance of this is that if front wheel brakes, no matter how well equalised, are applied on a corner and the front axle is not restrained from twisting the springs and giving the pivots a forward lean, the steering will become uncontrollable and run over on full lock. As self-centering is produced by the reaction between the tyre and the road and this is greatly increased when braking, any lean on the pivots has a much more violent effect on the steering when the brakes are applied than when the front wheels are rolling normally. Therefore this 'diving' of the steering on corners can be very dangerous, our tests having shewn that the wheel can be wrenched out of the driver's hands even though he is prepared for the occurrence. There are various methods employed to combat this difficulty. That most commonly used is off-setting the position of the axle on the front spring and increasing the rating of the front springs to the maximum compatible with the minimum riding comfort desirable. Placing the axle near the front of the spring contd. | ||