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).
Technical discussion on car body flexibility, comparing construction methods and materials like ash wood and aluminium panelling.
| Identifier | ExFiles\Box 5\2\ 02-page175 | |
| Date | 28th July 1928 | |
| (2) EV{Ivan Evernden - coachwork}2/28.7.28.cont. Ash is a good wood for using as a spring material. By this system the deflexion is spread uniformly over large areas instead of being concentrated at the joints. This avoids the fixings being heavily loaded, and all the stretching of the fabric taking place at the joints. We agree with Mr. Munday that very little shaping of the mdls would be necessary in most cases to provide the flexibility required. By twisting a standard door frame, such as is used for panel finishing, one can see that there is already considerable flexibility in the orthodox construction. Moreover, we do not believe that it is necessary for every portion of the body to be made flexible. We would suggest that the body be built rather on the lines of a hull of the common ship, i.e. it would consist of several bulkheads, joined by flexible timbers. The sections at the dash, windscreen, centre pillars and rear panels would be the bulkheads. The deflexions of the chassis frame in a vertical plane are very small. The chief deflexion which has to be catered for is that due to the twisting of the frame thus:- The various bulkheads, being individually attached to the chassis, under these conditions would assume positions relative to eachother thus:- The intervening rails, being securely fixed at the ends, would deflect thus:- In the case of the Weymann body the deflexion is thus:- This localised movement must destroy the fabric where it occurs. If the body be constructed as we suggest, it will be seen that certain of the curved corners which occur at places where no flexibility is required can be panelled in aluminium. We believe that few place would be left which had curves which would have to be produced by your laced steel method. The flatish panels of the sides might be filled with three-ply wood and padded out, as they would be only called upon to twist. As previously pointed out, there would be little or no matchboxing. We apologise to you for our remarks. We have criticised, but we hope that we have made our criticism constructive. Yours faithfully | ||