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).
Typed report on steering system design, discussing friction, ratios, and high-speed stability issues.
| Identifier | ExFiles\Box 17\4\ Scan032 | |
| Date | 7th June 1932 | |
| -2- He/B1.1/M.7.6.32.Cont'd.{John DeLooze - Company Secretary} We think that they are right to take the plain thrust washers out of the pivot because the friction here is greatest when the car is being shunted and lightness is most essential, but it is very doubtful whether such friction is effective to counteract joggles when the axle is dancing about at high speeds on the road. We attach a copy of our report He/B1.1/T. 22.9.26 which gives some tabulated information that we obtained experimentally on various axles we have had, showing the effects of various king pin angles. STEERING BOX. Going from the axle to the steering reduction the Americans use a very low ratio steering, say about 15 or 20/1 and a relatively in-efficient hour-glass type of reduction gear which, being often of the roller type, does not vary much with the presence or absence of the oil film. Generally speak-ing they have no side steering tube springs and consequently little'sponginess'. Our own worm and nut type of steering suffers from the fact that its reversibility is greater when under "joggling" conditions, than when parking. The attached report He/Rx./LG.19.7.31 shows some work we did on this. Again this peculiarity of the worm and nut type of steering having an efficiency which varies so widely between parking and joggling conditions is emphasised by the fact that going from a helix angle of 18' - 4' (.940 lead worm) to a helix angle of 7° 15' (.720 lead worm) did not help our joggling problem materially (He/M.1/LG. 22.3.29 attached), and the .900 large dia worm with its helix angle of 7° - 35' could not be expected to, and did not on tests, show an appreciable reduction in joggles either. We had a peculiar experience on Brooklands emphasising the effect of steering irreversibility. A Buick which we were testing got into a violent wobble at 80 M.P.H. and yet practically no effects could be felt on the steering wheel, in fact it was only the radiator and wing movement that told the story, the wobble subsequently being observed from another car. In this case immunity from road reactions could hardly be attributed to the axle. | ||