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).
Suggestion for an experiment to address high-speed wobbles by modifying the front axle suspension.
| Identifier | ExFiles\Box 29\1\ Scan314 | |
| Date | 21th June 1927 | |
| +457 As From Pt. to By H.E. C.W.R. War. At sea. 21/6/27. re high speed wobbles. Since leaving Derby I have been giving a good bit of thought to the above problem and am writing to know what you think of the following suggestion for an experiment,- Attach front axle to chassis by means of twin inverted cantilever springs on both sides of chassis,-the pairs of springs on each side to be assembled one above the other and connected to the axle by their forward extremities, the one some inches above and the other some inches below the axle centre,- the bracket for attachment would be solid with the axle, of course, and the springs would have solid forged eyes at both ends. The centre bearings of these springs would be immediately under the chassis side members while the rear anchorage would be well inside the side members further back so as to throw the two pairs of springs out of parallel,- that is, they would be splayed outward at their forward ends where attached to axle. By this means the torque reaction due to braking would be taken by the springs which I think would give a better geometrical job than the present torque anchorage to shock absorber arms. The wider sring seat centres on front axle would, I think, increase your weight damping on criss-cross period without interfering with your wheel lock. I do not think there would be any loss of lateral stability at forward end of chassis, while I would expect increased resistance of spring to torsion which might be beneficial to wobble by sending period up. The period would also be sent up, I suppose, by the decrease in unsprung weight. The attachment of springs to axle at wider centres than chassis frame would permit of using a much straighter front axle or perhaps a quite straight one which should simplify the braking torque problem. I realise that the front end of the chassis might have to be strengthened to carry frward engine support so far from spring support while the side members might have to be "upcast" to accomodate the bracket carrying the centre bearings of the springs also if these springs DID offer more resistance to torsion then the frame sresses might have to be reconsidered. Total chassis weight might be slightly increased, also. There will, of course, be a thousand technical reasons against the above suggestion but I don't mind that a bit if only you will be good enough to let me know what they are, that is, unless it would use up too much paper. Pf. | ||