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).
The ignition advance required to maintain power for an E.A.C. engine.
| Identifier | Morton\M20.2\ img002 | |
| Date | 12th July 1923 | |
| R.R. 493A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. Expl. No. REF: Hs{Lord Ernest Hives - Chair}/ACLL.4.24. E.A.C. ENGINE. Ignition advance required to maintain power. Figures obtained from 3-EAC-1 Engine - 4.6 comp: ratio. (1) Battery only. (2) Magneto (3) Both ignitions synchronized. In each case the positions given as max. and min. are where power is maintained, and 1° from 'fall off'. The average range for max. power is 8°. (1) Battery only. REVS. | LBS. | MAX. | MIN. | MEAN. 2500 | 113.5 | 54° | 47° | 50.5 2250 | 124 | 53° | 43° | 48 2000 | 134 | 50° | 42° | 46 1750 | 139.5 | 46° | 40° | 43 1500 | 143.5 | 44° | 38° | 41 1250 | 148 | 42° | 35° | 38.5 1000 | 149 | 39° | 32° | 35 750 | 150 | 36° | 27° | 31.5 650 | 148 | 33° | 25° | 29 (2) Magneto only. 2500 | 112.5 | ---- | 44° | 45° 2250 | 123.5 | ---- | 43° | 46° 2000 | 135 | 47° | 39° | 43° 1750 | 140 | 45° | 38° | 41.5° 1500 | 144 | 42° | 36° | 39° 1250 | 146 | 41° | 33° | 37° 1000 | 148.5 | 38° | 32° | 34.5° 750 | 151 | 35° | 28° | 32° 650 | 148 | 31° | 24° | 27.5° | ||