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).
Letter discussing American drop head motor car practices and torsional stiffness comparisons.
| Identifier | ExFiles\Box 178\2\ img087 | |
| Date | 11th January 1940 | |
| Copy of letter received from R.R.Incorporated. Rolls Royce Limited. Derby, ENGLAND. Jan.11, 1940. Rm{William Robotham - Chief Engineer}: Re: CAR WORK. Just received yours of Dec.22nd. While the General Motors Building is the best location in the world to pick up odd bits of information on the Industry, and while I propose to supplement this information by a fairly constant attendance at the S.A.E. meeting here next week, there are some of your twelve items on car work which cannot be answered offhand and will take a bit of study. However, let's see what we can do with them immediately :- Your Item No.1. The general American practice in making a drop head motor car is pretty lousy and obsolete. The best development along these lines is the Opel Cabriolet, Carl Stief having done the finest work in the Corporation along these lines. If you will pardon my saying so, the rigidity of the scuttle is not the most important item in producing a satisfactory cabriolet, although it may reduce the manifestations of torsional shake in the body-frame structure. The average American cabriolet is only good so long as it is run with top in place and it is always one of the major causes of headache in any manufacturer's shop. For convenience, it is just as well to put the thing down in figures. A satisfactory sedan car will have a torsional stiffness of the body-frame structure between the planes of the front and rear axles of more than 3500 pounds feet per degree. In actual American production, the stiffness is run all the way from about 3000 on Studebaker Champion which is definitely unsatisfactory, to about 8000 on the Lincoln-Zephyr. The new small Vauxhall has a torsional stiffness of around 5000 pounds feet per degree which compares with the Opel Kapitan. (continued)...... | ||