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 analysis of car body rumble, floor materials, and frame construction on various models.
| Identifier | ExFiles\Box 178\2\ img090 | |
| Date | 11th January 1940 guessed | |
| - 4 - at Vauxhall. We demonstrated that :- (a) The source of most present body rumble is the tin floor. (b) The only way to make a tin floor quiet is to crumple it up as on the Opel Kapitan. This non-flat floor is objected to in every country, except Germany. (c) The wood floor produced immediate drastic improvement in body rumble if properly applied; and on the contrary, produces no decrease in torsional stiffness. Most American cars to-day are about eight to ten decibels noisier than they should be by reason of the tin floor. The wood floor is cheaper and lighter. ' The Vauxhall is even worse than the average American car because of the four cylinder engine and relatively bad press work. I suggest that you should read Walter Appel's notes in the S.A.E. Summer Meeting Reports on frameless construction. His remarks, although very cautious, cover a considerable range. Your item No.4. The Chevrolet frame is the heaviest and most flexible frame on the American market. The frame section on the Chevrolet weighs over 200 pounds, whereas the allowance on frame for cars in this price class is between 150 and 170 pounds. It is a cheap frame to produce; and if it were properly harnessed to the body structure, it would be satisfactory on sedans. Attempts to use a similar frame construction on the Opel Admiral were entirely unsuccessful and an X-member had to be added at the last moment. My own picture on this subject is, therefore, that sedan cars will be production either frameless or with two boxed siderails, similar to Chevrolet, which will be extremely well attached to the body pillars. Cabriolet cars, on the other hand, demand an entirely different construction in which an X-member frame, or the equivalent in the way of a torsionally stiff underbody, is used. (continued) ....... | ||