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).
Steering tests for vehicle 12-EX, investigating a wobble issue at various tyre pressures.
Identifier | ExFiles\Box 29\1\ Scan261 | |
Date | 15th November 1926 | |
To Hs.{Lord Ernest Hives - Chair} from GWH.{George W. Hancock - Head Chateauroux} X457 GWH{George W. Hancock - Head Chateauroux}/LG15.11.26. STEERING TESTS ON 12-EX - WITH THE FOLLOWING CONDITIONS :- X7430 F4565 6.75" tyres. Tyre pressure 35, 40, 45 lbs/sq.in. (front) 35 lbs/sq.in. (rear) Friction in cross steering tube. Friction in lbs. at periphery of steering wheel 3.5. Lean of pivots 5o (backward). Side steering tube 1500 lbs. springs. With tyre pressures at 35 lbs/sq.in. a violent wobble can be easily set up, either by the sudden application of the brakes hitting a pothole, or the usual method of flicking the steering wheel. This wobble is almost impossible to hold and is developed at a speed of 25 m.p.h. keeping on until the speed is reduced to approx. 15 m.p.h. The danger of this wobble is that the steering is generally very good and would give an impression of a perfectly safe steering. There are less joggles felt on the wheel than when using the hydraulic damping. There appears to be less tendency for the steering to take charge on corners when braking. With the front tyre pressures increased to 40 lbs/sq.in. the wobbles are 25% less in violence and the peak is reduced to 20 m.p.h. It is also observed that the taking charge when cornering is reduced : This is very noticeable with the pressures increases to 45 lbs. This may be due to the present wet condition of the roads but it has not been possible to obtain a bad effect of taking charge under these conditions. The wobbles are reduced 50% and the wheel can be held easily. The steering generally is lighter for shunting and slow running, and it is quite good at high speeds. Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} | ||