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).
Vehicle dynamics, specifically slip angle, understeering, and oversteering when cornering.
| Identifier | ExFiles\Box 95\2\ scan0109 | |
| Date | 13th August 1936 guessed | |
| [Handwritten text at top] TORSION BAR = ROLL ROD X346 PH III Front Rasmussen GRY{Shadwell Grylls}/L.F.S. THE 20/25 DEMONSTRATES THE POINT WELL [Typed text] Regarding the location of the so-called torsion bar, the problem is as follows: assume a car making a turn at low speed. Then the radius of curvature of the turn will depend only upon the amount of turning of the steering wheel. Suppose we are in a turn and maintain our steering wheel in the same position. If you increase the car speed, the centrifugal force will increase proportionately to the square of the car speed. The centrifugal force acting upon the car mass has to be resisted by forces acting between the tire and the ground. Tests and analysis show that the only way the tire can transmit a force perpendicular to its plane to the ground is by deviating somewhat from the direction of travel which it followed when not subjected to this lateral load. The angle between the direction of travel of the tire subjected to lateral load and the tire not subjected to lateral load is commonly called "slip angle". This slip angle increases with lateral force. The vertical load on the tires might increase or decrease the slip angle depending upon whether the tire is lightly or heavily loaded. Now, if you consider the car in a turn, you will realize that the change in slip angle for the front wheels and rear wheels will be different mostly due to unequal loading. Furthermore, the outside wheels are more highly loaded than the inside wheels due to the overturning couple acting on the car. The result of this will be that with increasing speed the curvature of the car turn will change. If this radius increases, we say the car is "understeering", if it decreases we say it is "oversteering." Oversteering seems dangerous because the car has a tendency to get into a flat spin. As stated above, the | ||