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).
Ignition timing advance specifications, including a table of automatic advance versus engine speed.
| Identifier | ExFiles\Box 48\2\ Scan075 | |
| Date | 21th March 1924 guessed | |
| Hand advance 20 1/2° Auto-matic Advance 32 1/2° Total Advance 53° Automatic advance commences at 420 R.P.M and finishes at 2750 R.P.M advance Speed 5° 850 R.P.M 10° 1160 " 15° 1600 " 20° 1850 " 25° 2180 " 30° 2570 " 32 1/2° 2750 " | ||