Photograph showing a close-up of an engine, highlighting the carburettor and ignition system with a ruler placed for scale.
| Identifier | ExFiles\Box 102\1\ scan0053 | |
| Date | 19th November 1931 guessed | |
| IGNITION E 4 5 6 7 8 9 10 11 12 | ||
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).