Photographic comparison of AC, Lodge, and KLG spark plug insulators after endurance testing on Vulture, Peregrine, and Merlin engines.
| Identifier | ExFiles\Box 27\3\ Scan262 | |
| Date | 10th October 1939 guessed | |
| AC INSULATOR AFTER 50hrs ENDURANCE. LODGE INSULATOR AFTER 100 hrs ENDURANCE KLG INSULATOR AFTER 100 hrs ENDURANCE VULTURE(Experimental 6 CYL OHV LONG STROKE / Aero Engine) PEREGRINE(Experimental Bentley car never produced / Aero Engine) MERLIN(Aero Engine) | ||
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).