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).
Technical memorandum comparing suspension, steering and chassis details from Cadillac, Chevrolet, LaSalle and Chrysler.
| Identifier | ExFiles\Box 173\1\ img069 | |
| Date | 10th January 1934 | |
| Hs{Lord Ernest Hives - Chair} from Rm.{William Robotham - Chief Engineer} - 2 - Jan.10,1934 Plain journal bearings in pivots Ball thrusts " " Improved shackles for arms (4) The lengths of the parallel arms should be approximately conversely as their distance from the ground: Cadillac top arm 10" long " bottom " 20" long (5) As long as the front springs have an initial deflection of over 6", a good high speed ride will result, but to get a good low speed ride as well the front spring deflection must be greater than that of the rear springs. On the Cadillac, the rear spring initial deflection is 8", the front spring 9". (6) The steering they are using with the independent wheel suspension is the complete marles. (7) The measured torsional frame frequency at which they aim is 800 min. I do not understand how they measure this, as by our method it would be impossibly high. However, I will find out in Detroit. (8) Independent springing has added 5% to the cost of the Chevrolet, but on the Cadillac the increase in cost will be negligible. (9) To compensate for the very low rating front springs, anti-rolling devices in the simplest form of a rod in torsion are being used at the back. (10) G.M. are hard at it on the rear wheels. Oy. favours Burray's method with a somewhat longer arm to eliminate braking effects. Chrysler says that he will not have the propeller shaft tunnel any longer, that is why he is pushing independent rear wheels. (11) One of the main troubles with independent wheel springing has been too much self-centring on a corner. This is likely to be particularly noticeable with our equal length arms. Tyre wear is impossible on the Cadillac with this arrangement. (12) Tyre treads have had to be reconsidered in conjunction with independent wheel suspension. They are now more rounded instead of the old flat type. "Doughnut" tyres can be used on the new cars without trouble. (13) On the LaSalle they have pushed the rod and engine forward 9". In view of the fact that this information is from Oy. who cannot help being prejudiced in favour of the scheme he himself has sponsored, and also that I have never driven one of these cars on the road, the data should be taken as subject to qualification. It may, however, prove useful in getting out a preliminary lay-out of the SpectreCodename for Phantom III front end. I enclose a few cuttings shewing details of G.M. and Chrysler schemes. | ||