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).
Pros and cons of different independent wheel springing designs, focusing on tyre scrubbing and steering geometry.
| Identifier | ExFiles\Box 173\2\ img023 | |
| Date | 31th January 1934 | |
| To By from Da.{Bernard Day - Chassis Design} c. Ug-Wes. Hs.{Lord Ernest Hives - Chair} Hy.{Tom Haldenby - Plant Engineer} Independent Wheel Springing. Referring to By.3/G29.1.34, the usefulness of these suggestions seems to depend on the practical importance of the two inter connected deficiencies of our existing system and its adaptation, the unequal link system; viz. Track variation giving tyre scrubbing and/or gyroscopic reaction due to displacing the plane of wheel rotation. With regard to tyre scrubbing, it has to be remembered that our independent wheel suspension system as now arranged scrubs the tyres far less than does the present standard axle, for equal bumps, so that from this point of view there is no reason to suppose that the equal links giving parallel movement will present any difficulty. The principal drawback to the schemes suggested by By.{R.W. Bailey - Chief Engineer} is the increased number of joints and pieces. In the first scheme there are 16 bearings or more required against our 8, and in the second scheme 12. In the first scheme all the joints are fully loaded and those on the main links much more highly loaded than ours. The main links are also subjected to torsion in braking unless the lower auxiliary link is also a triangle involving extra bearings. In the second scheme the bearing loads are increased by the offset position of the wheel. In both schemes it appears to be impossible to get correct steering geometry without additional linkage and complications, so that unless the above two deficiencies in our system are found to be of more importance than we have any reason to think they will be, it seems unlikely we shall require the added complication of these schemes. In these schemes, as in ours, rolling of the whole vehicle deflects the plane of rotation of the wheels, and to the same extent. Scrubbing on our present equal links scheme, can be further reduced by setting the links towards the rebound. A reduction of 30% is possible this way with present proportions. E's proposals to put the springs outside the frame also offers possibilities on SpectreCodename for Phantom III of increasing the lengths of the links whereby a further considerable reduction could be obtained. | ||