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, comparing balloon and high-pressure tyres and testing front shock absorber adjustments.
| Identifier | ExFiles\Box 28\4\ Scan326 | |
| Date | 22th August 1925 | |
| R.R. 493a (50m) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. Expl. No. 4657 REF: Hs{Lord Ernest Hives - Chair}/Rml/LG22. 8. 25. To R# from Hs.{Lord Ernest Hives - Chair} c. to CJ. BJ. c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} 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. V457 x8430 Our further tests show that we can get somewhat divergent results on a car if we replace high pressure tyres by balloon tyres. The particular case which has arisen is that we found it more difficult to make our Silver Ghost car wobble than the Phantom car when both are fitted with high pressure tyres; with 7.3" balloon tyres, the wobbles produced are, if anything, worse on the Silver Ghost. We have tried the effect of front shock absorber adjustment with balloon tyres on a new PhantomCodename for PHANTOM I car. The balloon tyres were balanced to the best of our ability. They were run at a pressure of 20 lbs./sq.in. With no damping on the shock absorbers, we got fairly bad wobbles. With 25 lbs. loading on the shock absorbers the intensity of the wobbles was reduced by 10% - with 50 lbs. loading on the shock absorber, the wobble was reduced 50% - with 75 lbs. loading on the front shock absorber, the magnitude of the wobble was reduced by 80%. We are repeating our tests with shock absorbers and high pressure tyres. It will be observed that on our previous tests with high pressure tyres, it was necessary to have the wheels considerably out of balance to obtain a wobble. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||