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).
Technical letter discussing front axle modifications to improve stability by reducing wobbling and shunting.
| Identifier | ExFiles\Box 52\1\ Scan156 | |
| Date | 21th September 1928 | |
| Hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer} from DA. {Bernard Day - Chassis Design} c. to BY. {R.W. Bailey - Chief Engineer} X4474 X.4474 X.7420 DAL/M21.9.28. Thank you very much for your Hs {Lord Ernest Hives - Chair} /RmL/LG19.9.28. and for the literature about Mr. Sensaud de Lavaud's inventions. We will retain this for the time being as we presume you have done with it, at any rate for the moment. What we were actually wanting to see was the mathematical paper presented to the French Academy of Sciences - (this is of course amongst them). We have the English translation of the non-mathematical paper read before the American Society of Automotive Engineers. We are sending immediately to Derby drgs. of a new front axle for SS. {S. Smith} , giving 1.750 offset between the pivot and the wheel centre. We have also by retaining the present std. inclination of the pivot, increased we think as much as possible the distance between the centre of the wheel and the centre of the pivot. There are also one or two slight alterations. It appears to us that this axle should be better than the present std. in the following ways :- (1) By lightening the hubs and stub axles, and by pushing the hubs, the brake gear, the pivot and the steering levers in towards the centre of the car, we have increased the speed at which trampinn occurs. (2) By increasing the distance between the plane of the wheel and the pivot we have reduced the wobbling speed. These two alterations increase the difference between the two principle frequencies, and would appear to reduce the tendancy to self excitation. (3) The increased offset between the pivot and the wheel should reduce the effect of the gyroscopic shocks from the road by increasing the power of the opposing road shocks. (4) In all probability the shunting is improved by the increased rolling, the increased load on the pivot being, as it appears to us, negligible. You already have an axle possessing most of the aboge advantages in a slightly smaller degree - N.sch.2625 We are going to leave it to you to decide whether you will push forward with this l 3/4 axle for the first car, and put up with a certain amount of delay, or whether you will go forward with the original 1.5 offset axle. We think here that the alterations on N.sch.2718 are worth while. DA. {Bernard Day - Chassis Design} | ||