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 memo about rolling resistance, inertia torque, and their effects on steering geometry and wheel wobble.
| Identifier | ExFiles\Box 170\3\ img050 | |
| Date | 14th July 1933 guessed | |
| -18- Rolling Resistance and Inertia Torque We know from Goodyear tests that the actual resistance of tires increases with slip angle. We have built a small model which demonstrates an important fact, 1. Torque around the kingpin when the wheels are running free is proportional to wheel-plane offset x. All forces in wheel-plane are applied to car at c. 2. Torque when brakes are applied is proportional to ground offset y. All forces are applied at tire contact c. An approach to "centre point" steering by increasing kingpin angle and has no effect whatever on the varying torque about the kingpin produced by :- (a) Variation in wheel velocity due to variation in rotation speed of wheels on a wavy road. These inertia forces may be very large, for instance a wave 2 ft long and 1 inch high at 60 m.p.h. might produce on the Chevrolet a fore and aft inertia force of 700 lbs. applied at c. (b) Variation in rolling resistance. Such a centre point steering only reduce the torque about kingpin when the brakes are applied. However, variation in rotary velocity of wheel due to wobble is proportional to ground offset y. Looking at the sketch of wobble cycle, at B' the wheels are turning with maximum angular velocity to the right. The left front wheel therefore has | ||