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).
Two development schemes for improving vehicle damping and frame flexibility.
| Identifier | ExFiles\Box 15\1\ Scan087 | |
| Date | 12th March 1929 guessed | |
| -3- (3) The third conclusion was that logically there were two avenues of development : (a) To utilise the engine to the max. extent to damp the oscillations so that the period would never come up. (b) To proceed in the direction of making the frame sufficiently flexible to escape from the lower edge of the periodic wave band. This implied removing the X. member from the frame which for want of a better word was known as 'degutting the frame'. SCHEME (a). An example of (a) already tried was R's scheme of solid front feet with friction dampers - Lec.2634, and N.sch.2792 - at rear of unit, but the results from this early test were masked by lack of a good test road. It occurred to us that the optimum damping from the mass of the engine could be obtained by mounting the hydraulic dampers solidly on the engine arms, and allowing the power unit to float on soft rubbers in the frame. SEE ORIGINAL FOR SKETCH. We could not find an easy and quick way of trying this however, and on reflection it appeared equally effective for test purposes to use the solid front engine foot, making sure there was max. stiffness between the hydraulic dampers and the engine arms. This scheme was tried first without any rear friction damping and was at once a considerable improvement. Subsequently the friction dampers opposite the flywheel were added and it was a matter of opinion as to whether any improvement had been effected, but if any at all it was certainly better. We have R's recommendations to try still more and more damping, and we have yet to run this scheme with all the damping on. SCHEME (b). An SS.{S. Smith} that had always been rather worse than the others for frame 'shimmy' was taken and the frame X member removed, some temporary supports being provided for the brake gear. The engine was mounted on soft diabolo rubbers and with this combination the frame stiffness in torsion was not materially altered. contd :- | ||