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).
Specifying ignition timing settings for an engine.
| Identifier | ExFiles\Box 37\1\ scan 300 | |
| Date | 14th May 1925 | |
| X3949 14.5.25. X.8680/5. EAC. IGNITION TIMING. X.3949. Range of automatic control 28° Full battery retard 10° after top centre. Full magneto retard 12° before top centre. Point of synchronisation 16° " " " Full magneto and battery advance. 48° " " " the above figures referring to the hand advance. The coincidence of magneto and battery ignition occurs at 73° (out of 90°) advance of movement of hand control lever, 0° representing full retard. EFC. | ||