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).
Experiments to measure temperatures attained by the Goshawk ignition coil.
| Identifier | WestWitteringFiles\J\December1922\ Scan83 | |
| Date | 14th December 1922 | |
| To R & E.{Mr Elliott - Chief Engineer} from EFC. c. C.J. & FN. c. Hy{Tom Haldenby - Plant Engineer} & EF. c. Fg: & Ds. EFC2/T14.12.22. ORIGINAL. X.4079 - GOSHAWK IGNITION COIL EXPERIMENTS In accordance with your R2/M30.11.22, we have now made some experiments giving satisfactory results for the temperatures attained by the ignition coils, both in the engine position and on the bracket over the wheelcase, and in both cases both heat and electrically insulated, and uninsulated. This we have done by arranging a small copper wire resistance unit in a stabalite coil case cover with long leads running thereto, so that temperatures can be estimated by a change in resistance of this unit. In order to get a more direct reading of the temperature and to eliminate the slight effect due to the leads, the resistance-temperature calibration of this unit was first obtained by immersing the cap in an oil bath with a thermometer and taking the resistances with an accurate voltmeter and ammeter, making all the necessary corrections. Then the same instruments were used with the coil cover in position on the coil on the engine, the leads running through the window from the bench in our shop, upon which the instruments were stationed, to the car outside, with engine running with closed bonnet. The temperatures in five different cases were measured. No external spark gap was used and when necessary everything was done, e.g. advancing the ignition and strengthening the mixture, to keep the engine running as long as possible, so that the highest temperatures could be attained. | ||