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).
Modifications to the Wraith steering system to improve performance and reduce friction.
| Identifier | ExFiles\Box 9\7\ 07-page063 | |
| Date | 26th June 1937 | |
| To E.{Mr Elliott - Chief Engineer} from Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} c. By.{R.W. Bailey - Chief Engineer} c. Da.{Bernard Day - Chassis Design} c. Ev.{Ivan Evernden - coachwork} 650 Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer}2/AP.26.6.37 WRAITH STEERING We find that on the steering of the Wraith chassis, as on P.III., it is necessary to have no set up load on the side steering tube springs for freedom from joggles. The best compromise is obtained by the arrangement shewn on the attached Rm.{William Robotham - Chief Engineer}339, where the travel is 0.130 each way and the effective rating twice that of each spring. A further characteristic of the Wraith steering is that, as originally built, there is more friction than is necessary to prevent low speed wobbles, owing to the plain pivot thrust bearings combined with 4 cross steering tube joints. With only the outer spring in each cross steering tube joint there is still too much friction. We have therefore made experimentally ball joints as shewn on Rm.{William Robotham - Chief Engineer}337/8 which should have approximately one half the amount of friction. These ball joints are similar to those on the Cadillac. We have taken the opportunity of locking the lower pad by clamping it on to a conical seating by the cap. These joints Rm.{William Robotham - Chief Engineer}337/8/9 are fitted to the first Wraith III chassis 26.G.V1, and we should like your approval of them with a view to inclusion on the LOPs. They have already been detailed by By.{R.W. Bailey - Chief Engineer}'s Dept. Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} | ||