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).
Letter discussing suspension experiments, spring camber, and calculations for poundage for cars in Australian conditions.
| Identifier | ExFiles\Box 72\2\ scan0040 | |
| Date | 31th January 1928 | |
| Hs.{Lord Ernest Hives - Chair} Derby. C. to Whr.{Mr Wheeler} London. C.W.B. London. B.Y. Derby. E.P. Derby. X8990 I am in receipt of your Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}7/LG-21-12-27 and thank you for your remarks regarding the suggestion put forward by me re a third valve in each cylinder. It is very interesting to me to know the results of your experiments with turbulence and water cooling of exhaust valves etc., and I have to thank you also for this information. I have also received your memo. Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}6/LG-17-10-27 re suspension in reply to which I have to inform you that any experiments I intended carrying out here on the springs of my car, 47AU, have been held up by the non-arrival of hydraulic shock absorbers, the despatch of which was promised before I left Derby. I note that in your Hs{Lord Ernest Hives - Chair}/Rml/LG-2-10-27 addressed to B.Y. copy of which you enclosed, you variously describe the springs under the heading of "poundage and type of spring required" as follows:-- Re 82LC you mention "free camber" " London Trials Car "initial camber" " 8EX "positive initial camber" meaning, I presume, the same thing in each case. I think the term "initial" used both in connection with camber and deflection is rather confusing and could be changed with advantage in the case of deflection to the word "static". I will act upon your suggestion at the earliest opportunity and have the rear springs on my car altered from 2.5 positive initial camber to 1.4 positive initial camber and report to you again at a later date. I have been calculating the poundages of a great number of cars which have recently passed through my hands by way of inspection, picking out those which were noticeably well sprung for Australian conditions, and I find that the average of springing which appears to be well suited to local conditions can be arrived at as follows:-- Total weight on front wheels including passengers etc. less unsprung weight, plus 10%, divided by 2. gives average poundage for front springs. Total weight on rear wheels including passengers, baggage and full petrol tank less unsprung weight less 20% gives average poundage for rear springs. These figures have | ||