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).
Analysis of vehicle chassis dynamics, frame stiffness, and the effects of damping.
| Identifier | ExFiles\Box 4\6\ 06-page52 | |
| Date | 15th June 1931 guessed | |
| -4- This we drive with a flexible shaft from a variable speed motor. We can fasten it either to the wheel spindles or to the frame in any desired location. It shows up a number of things such as :- (a) Bounce of car on tyres without moving spring or shock absorbers. (b) Pitch of car on tyres. (c) Horizontal transverse flexibility of frame. Hitherto unsuspected. (d) Wobble of front wheels and effect of damping. (e) Tramp of front axle and effect of damping. (f) Rear axle tramp. (g) Torsional weave of frame. (h) Sag oscillation of frame. As far as we have gone it serves to show principally the great importance of such things as spare wheel mount, frame bracing and fender mount in actually controlling the frequencies of the assembly. When it is operating one can definitely feel the effect of damping, as the motor (as one accelerates) will fight to get free as it passes the natural frequency and eventually after a struggle will suddenly break away and jump as much as 150 R.P.M. The dashboard fixed to the chassis and bolted to the cowl by flexible means having internal friction is unquestionably a tremendous factor in keeping a car generally quiet inside over "corduroy" roads. Some American makers I hear are proposing to return to this construction which has been "out" for 15 years. In looking for frame stiffness we find that stiff side members are vastly more important and desirable than stiff cross members. Auburn with an X-shaped crossmember a la{L. A. Archer} Lancia are in the same trouble that you had on certain models. Thank you for notes about Bentley. Yours very truly, (Sgd.) Maurice Olley. | ||