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).
Analysing high-speed wheel wobble, gyroscopic couple, and potential solutions.
| Identifier | ExFiles\Box 71\2\ scan0070 | |
| Date | 12th June 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. -5- Expl. No. REF Hs{Lord Ernest Hives - Chair}/Rn{Mr Robinson}2/LG18:9.25. other than its natural period. Section 2. of the report is explained as follows. When water is poured on one drum the wheel descends and does not turn out, the reaction of the ground being removed. It therefore starts going up turned inwards and the opposite wheel, not having been turned in the air, descends turned out. When it meets the ground, its reaction being normal, it is turned in. But in being turned in, it promotes a gyroscopic couple which tends to keep its end of the axle on the ground and so opposes the criss cross movement. Hence the latter is damped and the wobble dies. When the cross steering tube is removed (section 4.) there is nothing to ensure that the descend-ing wheel meets the ground turned in, or in other words, that the gyroscopic couple engendered helps the criss cross axle movement. Thus the wobble cannot be sustained. If the gyros-copic couple of the wheel is neglected when formulating the theory which fits the facts, it is necessary to assume that when descending wheel hits the ground pointing in, there is a violent. force tending to turn it outwards, but when it comes down point-ing out, little force tending to make it turn in. We can find no data to substantiate such an assumption. Increasing the toe-in of the wheels will clearly increase the angle at which the wheel hits the road and so is likely to make wobbles worse which is borne out in practice. We have one unexplored means of solution opened up by this theory. That is, attention to the point of contact between the tyre and the road so as to minimise the road reaction when high speed wobbling. Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} | ||