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).
The effect of diagonal oscillation on axle pivots and steering stability.
| Identifier | ExFiles\Box 29\1\ Scan275 | |
| Date | 16th September 1925 | |
| - 3 - BY7/H.{Arthur M. Hanbury - Head Complaints} 16.9.25. -------------- All the foregoing is well understood but what seems to have been overlooked is the effect of the diagonal oscillation on the pivots of the axle. The pivots have two inclinations imposed on the pivot pin or axis:- a/- A lateral inclination to make wheel self-centreing. b/- A longitudinal inclination to give a castering effect to the wheel to increase stability in steering. It is the second one of these inclinations which is first of all affected by the diagonal oscillation, for if the offside wheel be "down", and nearside "up" in the seesaw, then a vertical line from the point of contact with the ground passes inside the pivot pin and tends to turn the offside wheel to steer to the left, and although the nearside wheel has the opposite action, the reaction between road and wheel is less than in the case of offside wheel, and in the case of violent motion the inertia of the nearside wheel will actually assist the turning of system in the same direction as with offside wheel. The above action is possible in spite of the lateral inclination of the pivot pin which normally centres the wheel, because for small motions like the early oscillation the returning of self-centreing moment of the lateral inclination is very small, and as the "surging" of the system increases, it is easily overpowered through a large range temporarily. Contd. | ||