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 curves against vehicle speed in miles per hour.
| Identifier | ExFiles\Box 163\7\ img284 | |
| Date | 7th April 1936 guessed | |
| DEGREES ADVANCE B.T.D.C. M.P.H. ROAD FIGURE OF IG. AGLE. JUST TO AVOID DETONATION. HEAD CLEAN SHELL N°1 PETROL PRELIMINARY DELCO REMY CURVE | ||