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).
Engine performance, propeller shaft shudder, and a detailed critique of the steering system.
| Identifier | ExFiles\Box 90\2\ scan0008 | |
| Date | 11th September 1936 | |
| - 3 - 11.9.36. is still needed are:- (a) The engine will not run comfortably on any fuel other than Discol as it knocks badly on most petrols, although it is not so bad when using Regent Super or Esso Ethyl. This feature is apparently not due to the ignition being over advanced as retarding the ignition to even a small extent causes a slight falling off in power. I have no objection to the use of Discol, but it is not always obtainable. (b) Idling: The engine will not idle comfortably under 600 revolutions a minute, which is rather fast and is apt to make it hot in traffic. Idling below this speed is not only uneven but sets up a nasty occasional thump, which is not cured by retarding the spark. I suspected plug trouble and bought a new set of K.L.G. 850 plugs but there was no noticeable improvement in the slow running. (c) Propeller shaft shudder: This is not noticeable in ordinary driving but it does occur when working slowly along in traffic, particularly in a slight up-gradient. It has, in fact, rather improved from when the car was first delivered. I have debated fitting a light form of Lanchester vibration damper on the prop. shaft to see whether this would deal with it, but it is not sufficiently serious to warrant the bother. (d) Steering: Compared with the average English or American car, of course, the steering is good, but compared with a Mercedes, B.M.W. or old type Frazer-Nash, it is some way behind. In my opinion springs in steering layouts are neither necessary nor good if the layout is geometric-ally correct, and even if some springing is necessary at the front end of the steering rod, it is certainly unnecessary at the rear end, and merely adds the mass of the steering rod to the other movable masses which have to be checked by the wheel. In my opinion it is definitely better that the mass of the steering rod should always remain in direct relationship with the wheel end of the steering gear. By eliminating the springs at the back end also, it is possible to reduce one of the frictional elements of the steering, as a solidly adjusted coupling ball with a set clearance of ½-thou. has less friction than a spring-loaded joint where the spring is always | ||