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).
Explaining the effects of front spring anchoring on steering joggling in a Bentley.
| Identifier | ExFiles\Box 87\4\ scan0080 | |
| Date | 28th June 1935 | |
| [Handwritten] GRY{Shadwell Grylls} & F.J.H. Should like to discuss Confirmatory tests with you. Rms. To from Da.{Bernard Day - Chassis Design} c. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Bentley - Front Springs Anchored at the Front. The following is the suggested explanation of why the steering joggling is less with the above arrangement as tried by Hancock than with the standard arrangement with spring anchored at the rear. (1) With the standard arrangement the geometry of the side steering tube is perfect on the bump and tends to move the ball end of the side steering lever towards the rear on the rebound. The gyroscopic couple tends to move the ball end of the side steering lever towards the rear on the bump and towards the front on the rebound. As a result (it is suggested) the full effect of the load due to gyroscopic torque is felt both on bump and rebound and especially on the latter. (2) With the spring anchored at the front the geometry tends to move the ball end towards the front both on bump and rebound. The gyroscopic couples being the same as in (1) the effect is that the load due to torque is felt in full on the bump, but on the rebound is much reduced or actually eliminated altogether, the ball being allowed by the geometry to move in the direction in which it is urged by the gyroscope. This should result in the new arrangement being superior over pot holes but inferior to the old over bumps. To explain this it is suggested the gyroscopic torque is much greater on rebound than it is on bump because of the limited rating of the tyres which is the only force available for upward acceleration, and has to overcome the force of the springs as well as the inertia of the axle whereas | ||