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).
High-speed wobble, comparing to American cars and proposing hydraulic steering gear solutions.
| Identifier | ExFiles\Box 29\1\ Scan196 | |
| Date | 23th February 1926 | |
| Oy6-E-22326 -2- February 23, 1926. Remember that no American car uses any form of servo system, so that their increase in braking is very "mild", and, with the increase in operating friction, the amount of twist on the front axle is not great. Packard on their 1925 model came out with softer front springs, under-slung below the axle, pivotted at the rear, and frictionless all-ball-bearing steering pivots. Also disc wheels on all models. But, although I had one of these Packards for eight months I don't really know whether there was a high-speed wobble in it, because I never drove it above 50 m.p.h. Other users of Packards tell me they are capable of shimmying with the best, but I will inquire further and let you know. Our wire wheels are very heavy and our brake drums heavier than anyone else's, so that probably we have about 50% more momentum in the rotating parts, 30% more in the axle itself and 30% more in the sprung weight on the front axle than any other comparable car. But I think the chief reason of our trouble as compared with American cars is that we really do travel at high speed for long periods and they do not. Hydraulic steering gear. You doubtless saw the suggestion of a hydraulic steering gear using an operating cylinder on the axle operating the divided cross-steering tube by means of a central piston and with a close fitted gear-type oil pump at the bottom of the steering column instead of the conventional steering gear, to produce pressure on either side of the piston on the front axle according to the direction of rotation. The danger of losing all control through breakage of a tube is pretty serious, but if radius rods were used it might be possible to use them for leading oil to the front axle and provide against leakage by an easy re-charging system. It might be a very beautiful smooth steering. It might be done in a different way. For example a conventional gear and side steering tube could operate an oil pump on the front axle in such a way as to move to and fro a central piston in a hydraulic cylinder on the front axle. Explanation of outward turn in contact mark left during wobble. In your reports you explain that the wheel meets the ground turned inwards and therefore the "castor" action will force it straight. But | ||