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).
Car body construction, discussing torsional rigidity, sub-frames, and issues with various chassis types.
| Identifier | ExFiles\Box 84\1\ scan0273 | |
| Date | 25th May 1934 | |
| - 2 - continued:- side members and a stiff cross close to the dash. This is the best solution, but it is not available. (2) To build the body on a torsionally rigid metal sub-frame and so mount this sub-frame that it will not be distorted by the chassis frame. We have used this system on Phantom for several years and abandoned it for the following reasons:- (a) It did not seem possible to recover the added weight of the sub-frame by a reduction in the weight of the super-structure. (b) It cost us money which we could not recover from the coachbuilder. (c) Because it relieved the chassis of the damping effect of the body front end, the jellying was increased and the high speed wobble occurred at a lower road speed. (d) The open body, the double enclosed cabriolet and the coupé almost died out and it was with these bodies having demountable heads, that it was of the greatest value. (3) To increase the torsional rigidity of the Coupé body as much as possible even at the expense of weight and cost, and so to construct it that even though it be torsionally distorted, it will deflect without knocks, rattles and creaks. This appears to be the only course open at present and I suggest that we might investigate the construction of the Coupé body on similar high speed chassis (such as the Alvis Speed "20") by Vanden Plas, Gurney Nutting, and Whittingham and Mitchell. The difficulties experienced with the Bentley are present also on the H.R. chassis when fitted with this type of coachwork, but due to the softer springing and damping of the latter, the heavier coachwork and the generally lower average speed, the rate of collapse of the body is less rapid correspondingly. Appended is a detail report on the body. 1985: IV. | ||