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 for a 20/25 engine with different governor setups.
| Identifier | ExFiles\Box 27a\1\ Scan201 | |
| Date | 17th February 1934 | |
| 20 25 HP IGNITION ADVANCE UNIT C.10. 6.3:1 COMP. RATIO OTHERWISE STANDARD 20/25 ENGINE 1) IDEAL CURVE (MIN. ADVANCE FOR MAX. POWER) 2) ACTUAL AUTO-ADVANCE BENTLEY GOVERNOR (INITIAL SETTING 16° BTDC) 3) ACTUAL AUTO-ADVANCE 20/25 GOVERNOR DEGREES B.T.D.C. (FLYWHEEL) R.P.M. (ENGINE) 500, 1000, 1500, 2000, 2500, 3000, 3500 10, 20, 30 C.T.S. | ||