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).
Solutions for vehicle joggle, tyre noise, and rear-axle steering issues.
| Identifier | ExFiles\Box 173\4\ img074 | |
| Date | 18th November 1935 guessed | |
| -2- relative to the steering gear itself on this point, but Olley seems fairly certain that the considerable wheel movement which we know in our scheme is the principal cause of our joggles. We shall find out more about this shortly. As regards tyre noise, Fraser says they overcame their troubles by fitting rubber bushes in the front shackles and got on well for a time, but that the noise has returned with the long tailed bodies and streamlined wings which they are now compelled to fit. They are, he says, now in trouble with tyre noise, and are overcoming it by attention to the tyres. He says our Buick has a specially silent tyre fitted, and other tyres should be tried before being too pleased with it. They are, however, fairly certain that a rubber bush in the front end of the rear spring will go a long way to cure it. The steering difficulty which arises when we try this, Olley says, can be overcome by lowering the front end of the spring a considerable amount, and this can be done by turning the edge downwards instead of upwards. Thus The effect will be to lower the centre about which the axle is swinging. This centre should be .75 of the half length of the spring horizontally, and 1.5 times the amount of the eye from the slots, in a vertical direction. It will be seen that this drops the centre compared with the spring as at present anchored, a large amount. Merely enlarging the eye of the present spring tends to make the rear-axle steering feature of the car worse because it increases the amount of offset from the spring plate. Lowering the spring eye produces an understeering characteristic which helps to stabilise the car. They do not know anything of wheels affecting the tyre noise and do not believe that they do, but body resonances due to body shape and wings, they are sure do. They are doing a great deal of work on tyres in connection with this and are going to let us see some of it. | ||