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).
Technical memo detailing steering improvements for the 40/50 HP model, focusing on overcoming high-speed wobbles.
| Identifier | ExFiles\Box 29\1\ Scan337 | |
| Date | 5th July 1928 | |
| To R: from Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} OY. c. to PN.{Mr Northey} CWB. Y457 Hs{Lord Ernest Hives - Chair}/Rn{Mr Robinson}2/LG5.7.28. 40/50 HP. STEERING. X7380 X7430 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 :- | ||