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 minimum ignition advance for full power on a 20 HP engine.
| Identifier | ExFiles\Box 54\5\ Scan303 | |
| Date | 7th March 1928 guessed | |
| NECESSARY IGNITION ADVANCE FOR 20 H.P. (CURVE SHEWS MINIMUM ADVANCE FOR FULL POWER) ENGINE No 11-GII COMPRESSION RATIO - 5.45 LONG DURATION CAMSHAFT ANGULAR DEGREES ADVANCE BEFORE T.D.C. R.P.M. OF ENGINE. LORRAINE-DIETRICH ENGINE SINGLE IGNITION DUAL IGNITION | ||