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 of ignition advance curves for various Phantom engine configurations against engine RPM.
| Identifier | ExFiles\Box 17\6\ Scan014 | |
| Date | 2nd December 1926 | |
| SHEET 2 IGNITION ADVANCE ON FLYWHEEL (DEGREES). R.P.M OF ENGINE. IGNITION ADVANCE CURVES. BOTH IGNITIONS ARE SYNCHRONISED IN ALL CASES. STD. PHANTOM (COMP. RATIO = 4:1 : 1) ALUM. PHANTOM (4.45 : 1) ALUM. PHANTOM WITH 1.600 DIA. VALVES, (COMP. RATIO - 4.69 : 1) ALUM. PHANTOM WITH HEAD TO L.C. 2230 (COMP. RATIO = 4.95 : 1) AHP 2-12-26 | ||