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. discussing the specifications and potential modification of 12 cylinder magnetos.
| Identifier | ExFiles\Box 43\4\ Scan096 | |
| Date | 29th November 1927 | |
| THE BRITISH MADE Watford SPEEDOMETERS & MAGNETOS. TELEPHONES: LONDON 1346 GERRARD WORKS: 622 & 623 WATFORD. NORTH & SONS, LTD. WHIPPENDELL ROAD, WATFORD. TELEGRAMS: AEROMAGS WESTCENT LONDON. AEROMAGS WATFORD. CONTRACTORS TO THE ADMIRALTY, WAR OFFICE, CROWN AGENTS FOR THE COLONIES, INDIA OFFICE. Governing Director: R.B.North Director & Works Manager: C.H.Kirby. Secretary F.Stockwell EFC3/T CHK/DEW.1. 29th November, 1927 Messrs. Rolls-Royce Ltd., DERBY. Dear Sirs, We thank you for your letter of the 26th instant and beg to say that the maximum movement of the control lever on our 12 cylinder magnetos is 15°. If retarded further than this the low speed performance of a screened magneto with braided couplings is under that called for by the Air Ministry Standard Specification. The actual range can, however, be increased by fitting an automatic advance mechanism which alters the relation between the rotor spindle and that of the spindle driving it. We enclose a blue print No.589-1 shewing the automatic advance mechanism which could be modified to suit your coupling. The range of advance given by this mechanism is at the maximum 30° movement of the rotor spindle so that the combined amount of hand and automatic advance could be 45° on the magneto or 30° on the engine. We trust that the suggestion put forward will meet with your approval in which case we shall be obliged if you will send us particulars of your coupling in order P.T.O. | ||