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 North & Sons, Ltd. regarding the modification of E.W.6 Magnetos, specifically the cam design.
| Identifier | ExFiles\Box 65\3\ scan0148 | |
| Date | 22th December 1927 | |
| X7791 SPEEDOMETERS THE BRITISH MADE Watford & MAGNETOS. NORTH & SONS, LTD. WHIPPENDALL ROAD, WATFORD. TELEPHONES: LONDON 1346 GERRARD WORKS: 622 & 623 WATFORD. CONTRACTORS TO THE ADMIRALTY, WAR OFFICE. CROWN AGENTS FOR THE COLONIES. INDIA OFFICE. TELEGRAMS: AEROMAGS WESTCENT LONDON AEROMAGS WATFORD. Governing Director: R.{Sir Henry Royce} B. North Director & Works Manager: C. H.{Arthur M. Hanbury - Head Complaints} Kirby. Secretary F.{Mr Friese} Stockwell EFC3/T. CHK/DEW.2. 22nd December, 1927. Messrs. Rolls-Royce Ltd., DERBY. Dear Sirs, For the attention of Mr. E.{Mr Elliott - Chief Engineer} Fowler Clark. -------------------- We thank you for your letter of the 20th instant regarding E.W.6 Magnetos and beg to say that we have now completed, and are sending you by passenger train, a further magneto No. 100,082 in which the cams are made to give a break of 80°. The cams on this magneto are shaped so that the points are open for 80°, at the end of which movement the opening between the points is .004" and from this position the contact is made rapidly. This is the only way in which it is possible to make cams which will give a definite break of 80°, as when the cams are made so as to permit the points to approach uniformly until they meet at 80° it is impossible to maintain the angle for any length of time, as the slightest amount of wear on the fibre heel reduces the angle through which the break is maintained. P.T.O. | ||