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).
Further notes on the performance of standard coils and spark gap tests.
| Identifier | WestWitteringFiles\D\April1920\ Scan4 | |
| Date | 16th April 1920 | |
| FURTHER NOTES- 16.4.20. It will have been noted that the maximum gap curves for the standard coils on the two sheets of curves herewith do not show so good a performance as a similar curve given under cover of our Ck{Mr Clark}3/T20.1.20 and further that they are not so flat. There is, of course, some variation from coil to coil, but coils which are being produced at the moment are undoubtedly better in this respect than some of the earlier ones from which these curves were taken. We have, for instance, increased the spark gap for regular firing in the production test from about 6 mm. to 8.5 mm. and a coil which will fire six 8.5 mm. gaps through the distributor without missing does not show so much difference between the two different polarities as a coil which is not so good in spark length. The present standard production gap of 8.5 mm. .340", is represented on the curves as a pencilled line. EFC. R.R. 235 A (100 T) (S F.{Mr Friese} 846. 6-8-19) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2460. | ||