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).
Investigating steering friction and wheel wobble on a 'Phantom' model.
| Identifier | WestWitteringFiles\N\July1925-September1925\ Scan114 | |
| Date | 1st June 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -2- Expl. No. REF: Hs{Lord Ernest Hives - Chair}/Nm2/LG21.6.25. C With 12 lbs. friction, the steering was not at all nice, high speed control of the car being bad as a distinct effort was required to alter the direction of the car at all in contrast to the present finger-light control. With 22 lbs. friction the steering was most objectionable. Front shock absorbers. We endeavoured to ascertain if we could affect wobbles by increasing the load on the front shock absorbers. We found that we could detect a slight difference if the shock absorbers were tightened up very considerably, but that the riding of the car was materially affected for the worse by the increased friction necessary. We should say that the improvement obtained in this manner was 15% to 20% as regards the intensity of the wobbles. Balanced wheels. We carried out a test on the "Phantom" to see whether we could induce the car to wobble with balanced wheels. We balanced the wheels statically on the hubs - they were to within 1 oz. at the rim. We have no means of balancing them dynamically. We used Dunlop 7.3" balloon tyres inflated to 20 lbs/sq.in. We found that we could get a very considerable wobble which behaved most consistently, coming up at 50 - 52 m.p.h. and going at 42 m.p.h. on the overrun. We took a chronograph record of these wobbles, one original of which we send you. It will be observed that the period of the wobble is again almost exactly that of the wheel revolution. The amplitude is in excess of 8° as the instrument was set to record only those wobbles contd:- | ||