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 from S.U. Carburetter Company regarding diaphragm shrinkage and noise issues in pumps used on the Phantom III model.
| Identifier | ExFiles\Box 149\4\ scan0036 | |
| Date | 23th May 1935 | |
| Copy Continued. 2. From: S.U.Carburetter Company. You will recollect that when we originally submitted the German diaphragm which you are at present using, we turned this down ourselves and went on to another type, also of German origin, and which we call our G.3. Two dozen samples of these were sent you on May 23rd 1935, but you decided to continue with the present form. The analysis tends to prove that practically the whole of the breakdowns have been due to shrinkage of the diaphragm, and it is also responsible for a considerable amount of the noise. [Handwritten: not the type we now have / PND] This diaphragm trouble is known to your Technical Dept. and it has now been practically decided [Handwritten: (has been)] to go on to the type which we have been using for the last twelve months with practically no trouble whatever. What has accentuated the trouble on your large delivery pumps fitted to your Phantom III model, is the intense heat under the bonnet, and it is for this reason that the position of the pump has been changed. It has always been known that the diaphragm material is hydroscopic, and of course, the action of the heat dehydrates it and causes shrinkage to take place, whereas with the G.3 material this is not the case. Our Mr. Skinner will take an early opportunity of coming up to discuss the whole matter with you, but we think it advisable that this report be considered before he comes. Mr. Skinner will be pleased to bring with him a detailed report of all the pumps you have returned if you wish. Awaiting your kind reply, and assuring you of our best attention at all times, we are, Yours faithfully, For THE S.U. CARBURETTER CO.LTD sgd. T.C.Skinner. | ||