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).
Table comparing maximum ignition advance settings for Ethyl and Discol fuels to avoid detonation.
| Identifier | ExFiles\Box 150\1\ scan0320 | |
| Date | 1st April 1938 | |
| -2- Rm {William Robotham - Chief Engineer} /FD. {Frank Dodd - Bodies} 3/WR.1.4.38. Maximum advance to avoid detonation - Ethyl 10 m.p.h. 10° BTDC 20 " 24° " Discol 10 m.p.h. 12° BTDC 20 " 24° " Rm {William Robotham - Chief Engineer} /FD. {Frank Dodd - Bodies} | ||