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).
Testing of Sphinx sparking plugs as a potential alternative to Mercury and Lodge plugs.
| Identifier | ExFiles\Box 50\2\ Scan067 | |
| Date | 4th October 1921 | |
| From R.{Sir Henry Royce} c. to C.J. X.1812. RE SPARKING PLUGS X.4295 X.1026. While away I was interested in looking over several samples of sparking plugs. I was favourably impressed with the ordinary standard plug supplied by the Spinx Company, and purchased a few of these, and my tests shew that they are worthy of further experiment, as they seem to suit our requirements so well. This is of some slight important, as you are at present somewhat unsettled for at least a second source of supply, the manufacturers of the Mercury plug not being very substantial and reliable people, and the fact that this plug is rather liable to cause preignitions. I have not at the moment seen a Lodge Plug which seems to fulfil our requirements. Anyway, I think it would be good if we could recommend in our instruction book, onr or two good makes of ignition plug especially suited for our engine, which have been tested by us, and been found to suit them. Kindly, therefore make a further test of Sphinx with steatite insulator, of hot wall form. R.{Sir Henry Royce} | ||