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).
Front axle oscillation, or 'axle rocking', observed during the London's Continental trials of chassis G.X.L.-60.
| Identifier | ExFiles\Box 58\1\ Scan136 | |
| Date | 2nd March 1926 | |
| "Hs{Lord Ernest Hives - Chair}" Copy X5950 Chassis G.X.L.-60 - London's Continental trials I have just tried this car after small adjustments we have made, and find it a very agreeable car to drive. The general performance is also very good. There is one point which I should like to raise and that is that this car seems particularly keen to set up an oscillation of the front axle, which M.{Mr Moon / Mr Moore} Sensaud de Lavaud (who has made a special study of this subject) describes as: "A distinct oscillation of the axle between the springs and the tyres, around a longitudinal axis". I think we call it "axle rocking". All cars of the present classic design have this fault in theory, some more so than others. This car seems to "charleston" at the slightest provocation and although I have not tried it at high speeds, I imagine it would be extremely unpleasant if a particular type of road were encountered suddenly, at say 50 m.{Mr Moon / Mr Moore} per hour. I have got such a road in the Bois de Boulogne. The general surface is good, but for about 500 yards the centre of the road has developed numbers of shallow pot holes (indentations). The result is that the bumping wheel sets up an oscillation of the axle, the opposing wheel appears to rock in sympathy with the the other; the rocking is pronounced on this car. The sensation is similar, but considerably less than the commencement of the real H.S. wobble, when one really thinks the day of judgement has arrived. M.{Mr Moon / Mr Moore} Lavaud says that the H.S. wobble is the combination of two distinct phenomena, viz the axle oscillation and the flapping of the wheels around their pivots. I am wondering if the resistances of the hydraulics on the 20 HP axle are not too high, and if in damping out one evil we have developed another. I do not want to experiment with this car, but I should very much like to play about with the front S.A. to find out if the pressures are influencing the trouble. You are perhaps perfectly aware of this tendency and agree that the present position is a compromise until we know more about other methods of controlling the front wheels. "PS" | ||