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).
Battery ignition faults on the Goshawk chassis traced to the electrical properties of the bakelite coil case material at high temperatures.
| Identifier | ExFiles\Box 45\4\ Scan060 | |
| Date | 19th November 1922 | |
| X4079a To R & E.{Mr Elliott - Chief Engineer} from EFC. EFCL/T9.11.22. c. C.J. & PN.{Mr Northey} c. Hy.{Tom Haldenby - Plant Engineer} & EP.{G. Eric Platford - Chief Quality Engineer} c. Rg.{Mr Rowledge} & Ds. c. Hor. for Mr. Brock. X.3485 - BATTERY IGNITION ON GOSHAWK. X4079a Further to our EFCL/T28.10.22, a further considerable amount of work in this connection has now been done on chassis in the Expl. Dept. also a number of tests made on the bench, and it is now clear that the phenomenon described in the above report is due to the electrical characteristics of bakelite or similar material, of which the coil cases are made, at relatively high working temperatures. It is now almost always possible to reproduce the effect on the Goshawk chassis by running with closed bonnet and closed radiator shutters until the temperature inside the bonnet approaches 90°C. It was noticed that, with the coil in this condition, by lightly drawing one's fingers across the outer surface of the case, a sensation was experienced like that of a mechanical knock, which, however, has turned out to be a definite electrical effect. On making more pronounced contact with several fingers at a time with the outside of the coil case, it was discovered that it was possible definitely to make the ignition misfire entirely and to cause it to resume upon removal. At the same time the tingling effect as of a leaky electrical discharge could be felt. Since this discovery, a whole lot of experiments have been done with :- Contd. | ||