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).
Test log sheet detailing spark test results for various configurations.
| Identifier | ExFiles\Box 63\4\ scan0017 | |
| Date | 26th May 1918 guessed | |
| (17) (79) ZR6/C/150/5/R/A Same as for advance. (80) ZR6/C/150/5/R/B No spark. (81) ZR6/C/150/7/A/A No spark. (82) ZR6/C/150/7/A/B No spark. (83) ZR6/C/150/7/R/A No spark. (84) ZR6/C/150/7/R/B No spark. | ||