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 comparing ignition advance required for maximum power on E.A.C. and Hispano engines, showing the effect of dual ignition.
| Identifier | Morton\M4.2\ img013 | |
| Date | 1st January 1923 guessed | |
| TITLE: IGNITION ADV. REQUIRED TO OBTAIN MAX. POWER ON E.A.C. & HISPANO. SHOWING EFFECT OF THE SYNCHRONISED DUAL IGNITION ON HISPANO. NOTES: E.A.C. & HISPANO GIVES AUDIBLE DETONATION TO APPROX 1000 RPM. HISPANO: GIVES AUDIBLE DETONATION TO 1000 RPM WHEN USING ONE IGNITION ONLY. WITH THE TWO IGNS. ON HISPANO THERE IS NO AUDIBLE DETONATION. Y-AXIS LABEL: FIRING POSN. DEGREES BEFORE TOP CENTRE. Y-AXIS VALUES: 50°, 40°, 30°, 20°, 10° X-AXIS LABEL: ENG. R.P.M. X-AXIS VALUES: 500, 1000, 1500, 2000, 2500 CURVE LABELS: E.A.C. HISPANO 1 PLUG HISPANO 2 PLUGS | ||