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).
Bearing tests, steering issues, geometry, and the effect of tyres on vehicle stability.
| Identifier | ExFiles\Box 101\2\ scan0079 | |
| Date | 24th August 1936 | |
| -2- Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}10/KW.24.8.36. We have got a good figure of merit on the bearings from one or two of the trials cars which have been running about, some of which have done 25,000 miles or so with reasonably good results. If you do break the bearings on 35-EX in France there is nothing we can do about it until we have got Hall's metal big ends ready for test. We are doing all we can to push these along. I am glad you are going to square up Sr's trials car for him. I note what you say about wandering steerings. I still believe that the two really bad cases I have tried were due to something partially seizing in the system, and the most likely thing I can think of is the thrust washer. However, I do not say that the grooved thrust washer will overcome all the 20/25 steering complaints. I have been wondering whether the steering geometry has any bearing on the directional stability of the car. Rovers were telling me that with flexible front springs they found that a small alteration in geometry made a large difference to the directional stability of the car. I believe you have a short pendulum lever at Chateauroux and could probably fix up a longer lever too and tell me whether we are in the best position for neither over nor under steering. Of course you will alter the steering ratio at the same time but you will have to make a mental allowance for this when you are doing the tests. One other thing which has of course a marked effect on steering is tyres. We think that the 20/25 rear tyres are heavily overloaded and in consequence their cornering power suffers. We want you to try the car with Ph.III wheels and tyres. You might be able to borrow them from Sr's car for a quick test round Paris; in the meantime we are sending you out a pair of wheels and tyres, which will in any case be useful as spares for the Ph.III. We expect the rear wheels to have more effect than the front ones. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||