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).
Analysis of ignition mis-firing issues, static induction, and the effects of using earthed versus insulated metal tubing for wiring.
| Identifier | ExFiles\Box 61b\4\ scan0204 | |
| Date | 25th February 1925 | |
| Contd. -2- EFCl/T25.2.25. mis-firing trouble was less pronounced with the insulating or unearthed metal tube (always supposing the wires to be bunched). Now that we are alright with both our battery ignition and magneto ignition generators, it would appear that we ought henceforth to use an earthed metaltube to ensure that the possibility of wrong firing due to the static induction effect is absent. We have not been content, however, without making further bench tests, and please find attached copies of my assistant's reports WA.{Mr Wallis}109 and WA.{Mr Wallis}110, the first one dealing with observations of the observed lengths of induced sparks (when all wires of both ignitions are run in the same tube) both from magneto ignition and battery ignition cables, and vice versa, which for the rest is self-explanatory; the second dealing with similar effects obtained with the experimental use of a metallic tube, first insulated and afterwards earthed, from which it appears that the presence of the insulated metal tube slightly increases the average statically induced effect, but that the earthing of this tube most definitely reduces it to almost negligible proportions. Apparently it would be undesirable, for other reasons, to use an insulated metallic tube, because of the sparks which can be drawn from the tube itself, and thus present some possibility of ignition of petrol vapour. Contd. | ||