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).
Report discussing frame stiffness, suspension damping, and vehicle handling characteristics at different speeds.
| Identifier | WestWitteringFiles\S\June1928-August1928\ Scan062 | |
| Date | 1st July 1928 guessed | |
| contd :- -2- The frame stiffness is worth having, because if we revert to single point mounting, which we can do in a few moments on our experimental arrangement, we get more road shocks. Alteration (3) would probably not make so much difference with the standard frame; we intend to make some tests to see. We attach a curve to indicate how much the frame was stiffened torsionally. The increased damping used on the front was more than we can expect to use without spoiling the low speed riding. Summarising the results : we now know how to get high speed selectivity without wobbles. We do not know how to get high speed selectivity and retain low speed riding comfort because the amount of damping required to fulfil both conditions varies some hundreds per cent. 12-EX was most comfortable on the run down to Le CanadelHenry Royce's French residence this year, but impossible, partly due to its stiff rear springs, at low speeds on the coast road, while 14-EX though a very much better compromise, has been criticised for instability at high speeds on undulating surface and lack of selectivity, though the low speed riding was astonishingly good. We do feel that if customers expect to use a speed range from five to eighty m.p.h. some means of varying the damping in the suspension between a pre-determined maximum and minimum would be a great asset. Certainly in this case when we put the front dampers back to standard we lost a great deal of the charm of the steering, though we did not get high speed wobbles, due to the altered wheel centres. contd :- | ||