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).
High-speed steering wobbles and the effects of out-of-centre wheels.
| Identifier | WestWitteringFiles\N\July1925-September1925\ Scan184 | |
| Date | 12th June 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. Expl. No. REF: H.S./L.32:6:25. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. BJ. c. to RG.{Mr Rowledge} H.{Arthur M. Hanbury - Head Complaints} c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} HIGH SPEED STEERING WOBBLES. 7457 X.8470 In the recent test on the centre point axle with the wheels 5 1/4" out of centre point, the out of balance had a moment of 5 1/4 ins. about the king pin. We were using a 2 lb. weight. With centre point steering this weight had no moment about the king pin. We carried out tests later in the day to see what effect the displacement of the 2 lb. weight from the king pin has on a centre point steering wobble. We found that with a centre point wheel, if we moved the out of balance weight 5" outwards, the intensity of any wobble was increased 75% from the drivers point of view. The criss cross movement of the axle does not increase to a very large extent, but the shocks on the steering are bad. This means that with our vertical pivot axle the tendency to wobble should have been 75% worse with the wheels out of centre point. Actually the tests shewed an improvement. Therefore some beneficial influence of considerable magnitude must have been at work. The only obvious cause is the tyres being 5 1/4" out of centre point. It seems hardly possible to take advantage of the result, as we can never approach this out of centre point with front wheel brakes. We are trying to check it with normal wheels set out. | ||