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).
Ability test of a spark-coil, comparing its performance against a Watford E6 magneto under various conditions.
| Identifier | ExFiles\Box 4\5\ 05-page120 | |
| Date | 10th December 1920 | |
| ROLLS-ROYCE LIMITED. INSTRUCTIONS. 88259 19 To Order No Customer's No. 2 (contd) Re: Ability Test of Spark-coil the Watford E6 magneto reported 10-XII-20 The ignition coil appears to do better than the magneto where the gap is shunted mainly by an inductance, but not so well where resistance predominates. Conditions | Gaps | Remarks Gap plain (no shunt) | 8.5 2 coils (series) prim. open | 7.25 " " " prim. closed | 6.0 " " " both prim. " | 2.0 | Fair sparking 1 coil prim. open | 6.0 | (at 4.5 revs) " " " closed | 1.5 Signed: Francis J Allen This Sheet must be filed on completion of the work. | ||