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 De Havilland discussing the merits of the Wellworthy piston ring and its application in sleeve valve engines.
| Identifier | ExFiles\Box 148\3\ scan0133 | |
| Date | 29th July 1936 | |
| ALL LETTERS SHOULD BE ADDRESSED TO THE COMPANY AND NOT TO INDIVIDUALS. THE DE HAVILLAND AIRCRAFT CO., LTD. DIRECTORS: A.S.BUTLER CHAIRMAN G.DE HAVILLAND C.C.WALKER F.T.HEARLE T. P. MILLS W.E.NIXON F.E.N.St.BARBE A.E.HAGG STAG LANE EDGWARE MIDDLESEX ENGLAND TELEPHONE: EDGWARE 0171 (8 LINES) TELEGRAMS: HAVILLAND PHONE, EDGWARE CABLES: BENTLEY CODE. ASSOCIATED COMPANIES IN AUSTRALIA, CANADA, INDIA AND SOUTH AFRICA LHP/EDC. 29th. July, 1936. W.A.Robotham, Esq., Rolls-Royce Ltd., DERBY. My dear Robotham, I was very pleased to hear from you in your letter of July 28th. and I certainly hope we shall not lose touch with each other on subjects of mutual interest. Regarding the Wellworthy piston ring I think I can say that I am responsible for this being introduced into this Country, and it certainly saved us a very great deal of trouble on the sleeve valve Daimler. As you know, the essential difference between the sleeve valve engine and the poppet valve engine is that the cylinder is never round or parallel, nor is it ever oval or bent twice in the same place. The unhappy piston ring, therefore, has a busy time correcting the vagaries of the cylinder bore. When, however, the cylinder is such that it is approximately circular and parallel, there must be a very sad state of affairs to require the use of Simplex rings. I would hate to infer from your letter that this refers to the new 12-cylinder Rolls engine, but if it does, I am wondering if you have tried taper piston rings, which are a winner for holding down vast quantities of oil which otherwise becomes objectionable. However, the Wellworthy rings CONTRACTORS TO THE AIR MINISTRY, DOMINION, COLONIAL AND FOREIGN GOVERNMENTS THROUGHOUT THE WORLD PROPRIETORS OF THE DE HAVILLAND SCHOOL OF FLYING . HATFIELD . HERTS ALL SALES ARE MADE SUBJECT ONLY TO THE COMPANY'S SPECIAL WARRANTY. | ||