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).
Specifications for minimum magneto sparking speeds and gear meshing.
| Identifier | ExFiles\Box 70\4\ scan0127 | |
| Date | 1st February 1925 guessed | |
| -3- Contd. gear wheel with the pinion is correct; incorrect meshing being indicated by an uneven rattle emanating from the distributor end of the magneto. (7) The slowest speeds at which regular sparking will occur on 5.5 mm. gaps in air shall now be ascertained and shall not exceed:- for (a) Fully advanced position 280 r.p.m. " (b) Central position 210 r.p.m. and " (c) Fully retarded position 180 r.p.m. Note:- The minimum sparking speed for each of the three positions can be taken to be that speed at which 72 consecutive sparks, without missing, are given by the magneto at some time within a period not greater than 5 minutes. MADE AT CHOXLEY EFC. | ||