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).
Continued analysis of spark plug performance, noting the effect of earthed electrodes.
| Identifier | ExFiles\Box 52\3\ Scan349 | |
| Date | 14th November 1919 | |
| Contd. -7- EFC {E. Fowler Clarke - Electrical Engineer} /T14.11.19. There is also the curious fact that with the hot electrode earthed, the length of spark obtained is greater than with the hot electrode insulated, and this doesnot seem to be entirely due to the effect of electrostatic capacity of the battery. The fact that on the chassis the best sparking direction appears to occur when the earthed electrode is negative, would suggest that a sparking plug in which the earthed electrode could be red hot and negative and the central electrode cold and positive would give the best results. EFC. {E. Fowler Clarke - Electrical Engineer} (For curves see X.3109) R.R. 256 A. {Mr Adams} 100 T. (N/K B'BY. {R.W. Bailey - Chief Engineer} 18-4-19) C.S. 2584 | ||