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).
Results of testing ignition coils with varying numbers of secondary turns.
| Identifier | ExFiles\Box 50\2\ Scan055 | |
| Date | 5th May 1921 | |
| Hs{Lord Ernest Hives - Chair}1/LG5.5.21 -2- Contd. magneto, the less exacting are our plug requirements. During these tests we have carried out tests on the coils. We have tried coils with 14,000, 16,000 and 18,000 turns on the secondary instead of the standard 21,000. We find that the coils with less turns on the secondary gave the worst results. If we fix the safety spark gap in the coil ignition, the same as on the Watford magneto, we get very similar results. Hs.{Lord Ernest Hives - Chair} | ||