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 report on tests conducted to understand and measure steering wobbles on a 40/50 chassis.
| Identifier | ExFiles\Box 32\5\ Scan201 | |
| Date | 12th January 1923 | |
| X1692 To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to SY. Hel/LG12.1.23. STEERING WOBBLES. X457 X1692/X3500 The wobbles referred to in these tests are the violent wobbles of the road wheels which shake the whole car and come on usually at about 10 to 15 m.p.h. on the R-R car. These tests do not refer to wobbles caused by out-of-balance wheels or those caused by the incorrect gerometry of the steering or those caused by the wheels striking an obstacle obliquely. We carried out the following test on a standard 40/50 chassis, which had the standard arrangement of steering, except that we removed the plain thrust washer on the pivot so as to reduce the friction and enable us to obtain wobbles easily. We fixed on to the front axle a counter operated by the trip mechanism off the cross steering rod so that we could count the period of the wobbles per minute. (One wobble consists of the wheel moving away from the normal position and back to the normal position.) We found that the period of the wobbles was 316 to 320 per minute. We proved that the speed of the car did not effect the period of the wobble. The period was the same if the wheels wobble was at 10 m.p.h. or at 15 m.p.h. We proved that the period was not altered by the size or weight of the road wheels: We tried 32 X 4 1/2, 895 X 135, 895 X 150 and 33 X 5 Palmer tyres which are larger than any tyres contd:- | ||