Tests and modifications to improve the steering on the 40/50 HP model, addressing high-speed wobble and ride comfort.
| Identifier | ExFiles\Box 14\8\ Scan068 | |
| Date | 5th July 1928 | |
| To R. {Sir Henry Royce} from Hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer} c.c. to BJ. Wor. {Arthur Wormald - General Works Manager} c.c. to E. {Mr Elliott - Chief Engineer} DA. {Bernard Day - Chassis Design} c.c. to BY. {R.W. Bailey - Chief Engineer} OY. c.c. to PN. {Mr Northey} CWB. 47380 Hs {Lord Ernest Hives - Chair} /Rm {William Robotham - Chief Engineer} 2/LG5.7.28. 40/50 HP. STEERING. 47430 7457 Two factors have always limited the selectivity of the RR. 40/50 steering at high speeds : (1) The danger of high speed wobbles. (2) Low speed riding comfort. For a long time we have been making tests to reduce the wobbling tendency of the 40/50. We have always known that if we could use 2000 lbs/1" side steering tube springs and 4° backward pivot lean with the new type axle, we should have a wonderful high speed steering. We strove to use this on 15-EX but ran into high speed wobbles and simultaneously road shocks which are always evident if a car is on the verge of wobbles. We believe that we have now produced a steering on which the troubles experienced on 15-EX are overcome, it certainly exceeds our expectations and gives the best high speed selectivity of any steering we have tried. We are using 4° pivot lean and 1500 lbs/1" s.s. tube springs. We have overcome the difficulty of high speed wobbles by : (1) Wheels pushed 1.75" out of centre point i.e. .5" more than standard. (2) Front of the frame stiffened torsionally (a) by X member under radiator. (b) by 4-point engine mounting. (3) By making low pressure side of the front dampers have the same pressure velocity factor as the high pressure side. contd :- | ||
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).