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 system design, focusing on worm and nut type steering, road shock immunity, and friction improvements.
| Identifier | ExFiles\Box 17\3\ Scan201 | |
| Date | 19th July 1927 | |
| contd :- -2- The conclusions that we made in Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG19.7.27 are therefore confirmed by our recent experiments, and we do believe that with the worm and nut type of steering it is very difficult to get complete immunity from road shocks by reducing the helix angles of the worm, because µ for parking is relatively so high that helix angles of less than 10° reduce the shunting efficiency materially, whilst for joggling µ is so low that road shocks remain largely unaffected for the minimum helix angles we can use if we are to be able to park our big cars in comfort and get a self-centering steering. Summarising our views at the moment, therefore, we are very well satisfied with the .720 lead steerings that are standard, now that we have learnt how to produce them. We feel that the best way to combat joggles is to gear the steering down to about 16-1 outside the box as on 14-EX, the car at Le CanadelHenry Royce's French residence. This alone magnifies the power of the drivers hand to resist joggles, but additionally enables us to increase the friction in the steering above our present limit without making parking difficult. When we require more friction in the system, we find we are already working to the limit of the cross steering tube capacity. On the sports car (15EX) we tried to get the extra load required, but the springs in the tube took a permanent set and we had to keep re-adjusting them in order to restore the poundage lost. On the car at Le CanadelHenry Royce's French residence we have in addition to the spring loaded cross steering tube, shunted friction in the pivots to N.Sch.2296 fitted with an 825 lbs. spring. | ||