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 from Cadillac Motor Car Company discussing vehicle shimmy and fender shake under various conditions.
| Identifier | ExFiles\Box 170\2\ img016 | |
| Date | 16th March 1931 | |
| CADILLAC MOTOR CAR COMPANY DETROIT, MICHIGAN CADILLAC and LASALLE MOTOR CARS March 16, 1931. Mr. E.{Mr Elliott - Chief Engineer} W. Hives, Rolls Royce, Ltd., Derby, England. Dear Hs{Lord Ernest Hives - Chair} / Rm{William Robotham - Chief Engineer}: Many thanks for yours Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer} 1/M.J. of Feb. 21st. Will write further about Delco valves when I have a little more time. Meanwhile am very glad to have your comments on the axle which agree with our experience. With regard to the effects of fender shake on wet drums, what I wanted to get at was to what extent shimmy (in the Rolls Royce sense) or "pseudo-shimmy" (in the Delavaud sense) was associated with fender shake. For example, suppose one could say that on wet drums with your small cams the fender shake was half what it was on dry drums, then one would anticipate that pseudo-shimmy (i.e. the swerving of the tire in closest contact with the road and consequent gyroscopic reaction on the axle) was present to a certain extent even in this lower-speed phenomenon. There are considerations which would point to this, for example:- (1) The "Belgian block" at the Proving Ground is found only 50% as destructive in wet weather. (2) I think one can detect a distinctly less tendency to fender shake on wet brick roads. (3) The front axle has under all conditions a tendency to criss-cross action while the rear axle has a tendency to parallel action. Now K²/ab for the front axle is higher than for the rear axle so one would anticipate the reverse of the observed tendencies unless gyroscopic effects set up by the wheels were always present in the front axle. (4) Independent front wheel jobs with the wheel-plane held parallel to the plane of the car by rigid means, show a persistent | ||