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).
Performance requirements for two Scintilla magnetos for the EAC.II engine.
| Identifier | ExFiles\Box 48\2\ Scan102 | |
| Date | 26th May 1924 | |
| X8790 To Wd. {Mr Wood / Mr Whitehead} from EFC. {E. Fowler Clarke - Electrical Engineer} c. Ey. c. Hs. {Lord Ernest Hives - Chair} EFCL/T26.5.24. X.4181 - SCINTILLA MAGNETO. X8790 In view of El/M24.5.24 and other considerations, it is considered desirable at this point to obtain two further Scintilla magnetos, similar to the one recently received, type AM-6-A, No.34937, having anti-clockwise rotation to suit EAC.II. engine. We found the magneto referred to have advances according to the slip attached (three copies to Wd {Mr Wood / Mr Whitehead} ). This advance performance is probably as nearly representative of that which we require as it is possible to get with a governor of the centrifugal type, but the ranges are not quite as large as we would like. Our general statement of the requirements would be as follows:- The total available firing range in magneto degrees should not be less than 60°. Of this, not less than 30°, and preferably as much as 35°, should be automatic advance and the remainder hand advance. The automatic advance should commence at a magneto speed not greater than 450 r.p.m. and attain its maximum of 30 - 35° at a speed not greater than 3300 r.p.m. At the half-way intermediate speed of 1875 r.p.m. we should like as much as two-thirds of the advance to have occurred, and failing this, as much more than half the total amount as possible. Contd. | ||