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).
Objections to irreversible steering systems, analysing high-speed wobble and the effects of tyre size.
| Identifier | WestWitteringFiles\S\March1928-May1928\ Scan085 | |
| Date | 2nd April 1928 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} OY. ORIGINAL Hs{Lord Ernest Hives - Chair}/Rn{Mr Robinson}2/LG2.4.28. Handwritten: V8430 X457v V5430v 20 HP. & 40/50 STEERING. With reference to RL/M25.3.28. Our objections to an irreversible steering are as follows :- (1) Marked increase in tendency to high speed wobble. (2) No self-centering or feeling of selectiveness; this was the main complaint on the Continental Phantom even with its partially reversible steering. (3) Liability of fracture of parts. The Mercedes racing cars broke parts from trying to do high speeds with irreversible steerings. (4) Lower parking efficiency, and, if our present type of worm and nut are to be retained, difficulty of manufacture to prevent stickiness. It is rather difficult to estimate exactly the proportion which gyrostatic couples plays in the phenomenon, more especially as we have much contradictory evidence. For instance, in the last 10,000 miles test on 12-EX we found that with 6" balloon tyres, both traction and triple stud treads, the steering was impossible, with 6.75" tyres the steering was vastly improved. The only obvious difference was that the 6.75" tyre had a greater moment of inertia than the 6.00" tyre. Our own impressions are that increasing the moment of inertia of the wheel assembly reduces road shocks and decreases the tendency for a high speed wobble to start, but that whenever and if ever the wobble does start, it is liable to be worse than with the lighter wheel and tyre. Our experience with the Lancia (which we made wobble) and the Cottin Des Gouttes which also wobbled very contd :- | ||