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 table of various magnetos, detailing their types, numbers, lowest speeds, and performance remarks.
| Identifier | ExFiles\Box 4\5\ 05-page151 | |
| Date | 25th July 1922 guessed | |
| -2- Contd. | Magneto | Type and number | X. No. | Lowest speeds. | | | Remarks | |--------------|-----------------|--------|----------------|--------|-------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | | | | Adv. | Cent. | Retd. | | | R.{Sir Henry Royce} Bosch. | Z.R.6. | 427. | 260 | 170 | 246. | Advanced position same as maker's. Retarded position 2.5º earlier than maker's. | | | 2571226. | | | | | | | U.S.A. Bosch.| Z.R.6. | 3916. | 120 | 162 | 240. | Advanced position same as maker's. Retarded position 3.5º earlier than maker's. | | | 2992784. | | | | | | | Dixie. | Aero 648. | 3724. | 180 | 180 | 185. | Sparking speed unaltered by advancing or retarding, hence figures as first obtained on maker's range are representative. | | | 718237. | | | | | | | Conner. | C.M.1 | 4210. | 350. | 260. | 170. | (Weighted averages of two sets of figures) Retarded position same as maker's, this position giving minimum regular sparking speed. Further retard again increased speed rapidly. Advanced position 14.5º later than maker's. | | B.T.H. | F.M.6. | 3515. | 244 | 192 | 220. | Advanced position 10º earlier than maker's. Further advance limited by fouling of timing lever, but apparently would further reduce the minimum sparking speed in retarded position. Retarded position 21.5º earlier than maker's. | | | R.311941. | | | | | | DATA OBTAINED ON R.A.E. MK V TEST RIG | ||