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).
Model built to investigate the 'centre of percussion' in the Phantom and 20HP chassis suspensions.
| Identifier | ExFiles\Box 67a\1\ scan0149 | |
| Date | 20th April 1926 | |
| To HS{Lord Ernest Hives - Chair} from DA.{Bernard Day - Chassis Design} X8410 Da{Bernard Day - Chassis Design}3/M20.4.26. PHANTOM SUSPENSION - X.8410. We have made a small model of a bar carrying weights suspended from two springs of different stiffness, and though it is of an elementary character at present we can demonstrate on it that there is a point along the length of the chassis which remains still when the bar is oscillated with a small amplitude but fairly high frequency from the front end. We are suggesting that the cause of the difference between the Phantom and the 20HP. chassis is that this centre of percussion lies very much nearer the back axle in the latter than the former. Obviously the nearer a passenger is seated to this point the less blows from the front are felt. We wonder whether you think it worth while by vibrating a chassis at a speed more than either of the road spring speeds, to find where this centre of percussion occurs on our two chassis, the latter being loaded up in much the same way as on the recent tests. DA.{Bernard Day - Chassis Design} | ||