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 petrol gauges, Phantom II brakes, valve springs, and tyres.
| Identifier | ExFiles\Box 19\3\ Scan157 | |
| Date | 13th February 1930 | |
| OY. From Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}7/MJ.13.2.30. X7772 X452T X389T We regret not having replied to your previous letter before, but we have daily been expecting to hear of your departure from America. (1) PETROL GAUGE. We note the very interesting remarks of the K.S. Petrol Gauge Co. Of America re. the instrument we are at present using. At the moment we are not satisfied with the fluid column U tube intrument. The complication of having three lines between the tank and the dashboard is undesirable as is also the possibility of loss of measuring fluid by minute leakages in the pipe line. We therefore have a leaning towards the Bourdon type of gauge coupled to the Sprengel unit which is what the Nivex people are at present offering us. This gauge will take a tremendous amount of overload so that a pressure balance line to deal with the high filler on the tank is unnecessary. Additionally, the manufacture of the Bourdon gauge has been so perfected that it can be thrown on the floor without damage. Further, it has a round dial which matches the other instruments. Therefore, since we have the continuous reading, we are inclined to this gauge and are at the present moment testing it out. (2) APPARATUS FOR SHAVING PHANTOM 11 REAR BRAKES. This has not proved entirely satisfactory in operation and is not being used on production. It is possible that when we have a little time to devote to it it may be perfected, but at the present moment would be no use to you. (3) VALVE SPRINGS. We should be most interested to try a set of the springs which have been developed on your side. Apparently they will fit the Phantom ll engine. (4) TYRES. We know that a drop centre rim is still only used to a small extent in the States. We hope you will be able to put up with it as it will simplify testing enormously if we have a common ground for tests on steering, frame jellying and riding comfort, all of which are dependent upon the tyre. Incidentally we are having a most interesting campaign on frame jellying at the moment. We have proved that radiator jellying is but a minor form of high speed wobble and that the axle is at the bottom of the trouble, the frequency of the radiator dither being exactly in step with the criss-cross axle period as we have always suspected. Since we can find no means of preventing the axle | ||