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).
Comparison of performance characteristics for various magneto models.
| Identifier | ExFiles\Box 4\5\ 05-page320 | |
| Date | 3rd November 1924 | |
| Contd. -4- EFCL/T3.11.24. The above is not strictly comparable because the R.{Sir Henry Royce} Bosch machine has a much bigger range and the B.T.H. a smaller range than the Watford. In comparing, however, the Bosch magneto on the same range as the Watford, reckoning downwards from the advanced position, it was found that the speed limits could not be extended, i.e. the more advanced retard did not appreciably lower the 900 r.p.m. By selecting, however, the range upwards from the fully retarded position, it was possible to increase the range from 900 to 2500 r.p.m. this really indicating that the full advance of the magneto as originally arranged was too much. This feature of too much advance we have noticed on previous Bosch machines. In the cases of Scintilla AM-6-A No. 28531 and AG-6-A No. 34903 magnetos, it was observed that neither of these magnetos were capable of regularly firing this leaky gap over any speed range, the former would not spark regularly at all at any speed, and the latter would only spark regularly for any position of the advance lever at one speed, viz. 1200 r.p.m. The maximum speed at which it would spark regularly in the fully retarded (hand range only) position was 2050 r.p.m. and the minimum speed at which it would spark regularly in the fully advanced (hand range only) position, was 770 r.p.m. Contd. | ||