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).
Performance issues and modifications made to Goshawk ignition coils, including paraffin waxing and adding insulation.
| Identifier | ExFiles\Box 45\4\ Scan047 | |
| Date | 28th October 1922 | |
| Contd. -2- EFCl/T28.10.22. production tests as they had already previously received on the bench, their performance was found to be poorer and not again to comply with the performance specification. The weakness at that time was thought to be due to temporary leakage or dielectric losses in the insulation of the secondary winding, as it was found that by boiling the coil in paraffin wax the performance on the bench could be decidedly improved. Also for a time it seemed clear by results that this process definitely improved the action on the chassis. At the same time, however, we arranged for improved secondary insulation in the form of three thicknesses of .00075" paper, total .00225", in place of two, being prepared for the reduced number of secondary turns which might result. It transpired, however, that the winder was able to give us this extra insulation without reducing the number of secondary turns. All Goshawk coils on production chassis previous to this modification have been removed from their cases and paraffin waxed with some improvement, and now a number of the coils with extra insulation, also paraffin waxed, are available and tests have been made with some of these. Though an improvement has resulted, even now on some chassis the ignition is not free from the phenomenon. This occurs as would be expected, in the most unfavourable condition for the ignition, viz, hot condition of engine and ballast resistance, acceleration or slow running under load with | ||