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).
Ignition wire tubing materials to mitigate heat exposure and prevent static induction.
| Identifier | ExFiles\Box 52\1\ Scan092 | |
| Date | 24th October 1928 | |
| X7560-4473 To R. {Sir Henry Royce} & E. {Mr Elliott - Chief Engineer} from EFC. {E. Fowler Clarke - Electrical Engineer} c. BJ. Da. {Bernard Day - Chassis Design} c. Ev. {Ivan Evernden - coachwork} Wor. {Arthur Wormald - General Works Manager} EFC {E. Fowler Clarke - Electrical Engineer} 2/T24.10.28. SS. {S. Smith} IGNITION WIRE TUBING. X3714 On the SS. {S. Smith} engine we feel a little concerned with the exposure of one of the ignition wire tubes and ignition wires to the radiant heat of the exhaust manifold, and we have noted E's query as to whether these tubes could now be entirely non-metallic. We suggest that both tubes should now be bakelite covered metal tubes with the necessary provision for earthing the metal. We have little doubt that the bakelite is capable of withstanding the radiant heat better than the ebonite covering of the present metal tubes. It will be remembered that the reason we wish to keep to the earthed metallic tube on the 40/50 chassis is on account of the occasional phenomenon of static induction from wire to wire. This is a phenomenon that could scarcely be produced at all at will, but which does occur sometimes when either both sets of ignition wires or the two sets separately pass through tubes of insulating material which are not provided with a metallic tube for earthing purposes. It appeared to us from some tests we made on the bench that the likelihood of the occurrence of such a phenomenon was considerably increased by having both sets of wires in the same tube, the explanation being that it would occasionally happen that magneto and battery impulses of the same sign occurred at the same electrical instant, and their effects combined together to produce on a third wire a static charge | ||