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).
Improvements to engine ignition systems, specifically spark gaps and coil windings.
| Identifier | ExFiles\Box 183\M22\ img056 | |
| Date | 30th December 1919 | |
| TO BN.{W.O. Bentley / Mr Barrington} from R.{Sir Henry Royce} -2- R1/G30/12/19 Contd. metal tube for the conductors, because it has been determined that doing this allows of a fairly considerable increase in the length of the spark gap on the battery ignition plugs, and if so, would enable us to get more uniformly good slow running, and avoiding some of the risk of chunking in the transmission. In conclusion, I should like Mr. Hives and Mr. Clark to jointly determine how we can profit by still further increasing the length of the spark gap from the present .030" to perhaps .040". In another memo I have suggested that since we have confirmed the former evidence that increased insulation between the layers of the secondary winding as was found to increase the reliance of the coils without shortening the length of the spark, we might try still further increasing the insulation, as I am sure the maximum insulation is more [handwritten: significant] satisfactory than the maximum quantity of wire. I should also like a coil winding with a secondary of a fewer number of turns of larger gauge wire, which would possibly give a better spark and give equally effective ignition with less distance between the spark gaps and less strain on the insulation, so that we have a series of experiments in which - (1) We are increasing the spark gap. (2) Still further increasing the insulation between every layer of secondary winding. (3) The use of a lower tension, and greater quantity in the secondary discharge, that is, the possibility of a hotter and shorter spark, being better for the battery ignition. R.{Sir Henry Royce} | ||