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).
Cause of cracking on a continental touring saloon body, potentially related to chassis rigidity and diamond engine mounting.
| Identifier | ExFiles\Box 12\6\ 06-page028 | |
| Date | 16th March 1932 | |
| X7830 E.{Mr Elliott - Chief Engineer} FROM DA{Bernard Day - Chassis Design}/EV.{Ivan Evernden - coachwork} DA{Bernard Day - Chassis Design}/EV{Ivan Evernden - coachwork}7/M16.3.32. C. to HS.{Lord Ernest Hives - Chair} CX.{Major Len W. Cox - Advertising Manager} P. 2. CHASSIS. and DIAMOND ENGINE MOUNTING. X.5830 X.7830 X.7005 Messrs. Barker & Co. say that the introduction of diamond engine mounting has so reduced the torsional rigidity of the chassis that it accounts for the cracking up of the latest continental touring saloon. I saw this car on Monday and studied its design on a replica. I do not believe that there is any direct evidence to prove their statement. The other car that cracked similarly was 26-EX., which was a Barker body and had not diamond engine mounting. The body has been adequately and correctly plated with steel directly below the panels but I believe it is a physical impossibility to produce such a body in which the panelling is all in one from the scuttle to the back of the body. Three narrow strips of aluminium run into a domed solid corner (see sketch), in which two sharp angles occur. Movement cannot be avoided, and any movement, however, small, will cause a crack to occur at the point of rapid change of section and opposite the sharp corners. I recommend the panels in future be jointed at this point to allow movement, and suggest we should instruct coachbuilders to this effect. In view of the possible increase in torsional flexibility, I suggest that in all cases except those of the De Ville fronted cars (and cabriolets if any) the rigid attachment of the body to the frame at the dash should be deleted in the case of the 25HP, and P. 2. This does not occur on P. 2. cars having a subframe. A Hooper car - not with eddy-free front- has not cracked yet. It will be appreciated that the particular continental touring saloon in question has just undergone a very arduous 10,000 miles of wobbling and jellying. (1) | ||