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).
Analysis of vehicle suspension, axle movement, and ride comfort at various speeds and road conditions.
| Identifier | WestWitteringFiles\S\September1928-October1928\ Scan203 | |
| Date | 29th October 1928 guessed | |
| contd :- -2- velocity increase up to 2 ft/sec, but from this point upwards a rapid rise in pressure would be desirable. The max. velocity we have to deal with is about 5 ft/sec. Even this, it appears, might affect the low speed riding under certain conditions. This confirms our previous experience that we cannot incorporate too much pressure velocity increase without making the car ride harshly on pot-holes. The difference in amplitude between the fundamental spring movements and the secondary axle movements, however is much more pronounced. Under the majority of conditions the small axle movement does not seem to exceed 1", while on an average main road at 45 m.p.h. the fundamental car movement averages about 2.5". Therefore an increase in pressure with displacement should improve the high speed control of the car without spoiling the low speed riding. This should become more pronounced on wavy roads, level crossings or humped back bridges, the places where an insufficiently damped suspension gives most trouble, because the amplitude of the car movement goes up to 7", 9" or even 11". The curves given naturally indicate axle behaviour which it is difficult to translate into riding comfort. The test certainly shews why it is so difficult to control the car at high speeds with a shock absorber and yet retain good low speed riding. The max. velocities attained by the rear axle are much less than we anticipated. These figures will be of assistance to us in future tests on shock absorbers which we have been running much too fast. contd :- | ||