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).
Frame cross rigidity tests conducted on quarter-scale models of various designs.
| Identifier | ExFiles\Box 94\4\ scan0044 | |
| Date | 22th May 1935 | |
| To E.{Mr Elliott - Chief Engineer} from Ev.{Ivan Evernden - coachwork} E/Ev.{Ivan Evernden - coachwork}3/MN.22.5.35. FRAME CROSS RIGIDITY. Tests were carried out on four ¼ scale frame models to discover the relative rigidity of various frame cross designs. The test rig is illustrated in Diagram 1, attached herewith. Torque was applied to the cross and the amount of twist measured by the deflection of a straight-edge placed across the free ends of the frame. A deflection of .0035 is equivalent to 1 minute of transverse twist. Fig.1. SpectreCodename for Phantom III. The model of the SpectreCodename for Phantom III frame began to take a permanent set when 202 in. lbs. of transverse torque were applied. The top and bottom plates of the central box became cupped inwards, having collapsed under compressive load. Fig.2. SpectreCodename for Phantom III. A plate of sheet steel of the same gauge as the cross (.018") was sweated to the top and bottom of the cross, and the test was repeated. It will be seen that we increased the rigidity of the cross 30%, and the torque at which permanent set occurred was put up to 296 in.lbs., - an increase of 46½%. Fig.3. This was a model of an orthodox design of cross such as is used on many American and Continental Cars. In dimension it was the same as the SpectreCodename for Phantom III. It will be seen that the rigidity was distinctly inferior to that of SpectreCodename for Phantom III, its rigidity being approximately 38% less. Permanent set occurred at 135 in. lbs. of transverse torque when the top and bottom plates at the centre of the cross buckled. Contd: | ||