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).
Graph showing various spark advance curves against RPM for the Phantom II No. 25 large bore unit.
| Identifier | ExFiles\Box 92\2\ scan0158 | |
| Date | 22th May 1933 | |
| [ "PHANTOM II No 25 (LARGE BORE UNIT)", "RMP 58", "GR{George Ratcliffe}", "S.S.1", "SPARK POSITION", "° ADVANCE OF T.D.C", "STANDARD LONG TYPE", "SILENCER CUT OUT OPEN", "IDEAL MAGNETO CURVE", "AUTOMATIC ADVANCE MAGNETO CURVE", "IDEAL BATTERY CURVE", "AUTOMATIC ADVANCE BATTERY CURVE", "R P M", "S.S. Laadman", "22/5/33" ], | ||