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 the necessary ignition advance for a 20 HP engine.
| Identifier | WestWitteringFiles\S\March1928-May1928\ Scan019 | |
| Date | 7th March 1928 | |
| NECESSARY IGNITION ADVANCE FOR 20 H.P. (CURVE SHEWS MINIMUM ADVANCE FOR FULL POWER) ENGINE No II-GII COMPRESSION RATIO = 5.45 LONG DURATION CAMSHAFT ANGULAR DEGREES ADVANCE BEFORE T.D.C. 50° 40° 30° 20° 10° R.P.M. OF ENGINE. 500 1000 1500 2000 2500 3000 LORRAINE-DIETRICH ENGINE SINGLE IGNITION DUAL IGNITION V265. | ||