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).
Winding test of a spark-coil, comparing its performance against a Watford E6 magneto.
| Identifier | ExFiles\Box 37\1\ scan 090 | |
| Date | 30th December 1920 | |
| RR 300 (120B) (SF 349 24-1-19) MP 200552 88259 ROLLS-ROYCE LIMITED. INSTRUCTIONS. To Order No. Customer's No. 2 (contd) Re Widing Test- of Spark-coil. the Watford E6 magneto reported 30-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 | Gap mm | Remarks Gap plain (no shunt) | 8.5 2 coils (series) prim. open | 7.25 " " " 1 prim closed | 6.0 " " " both prims. " | 2.0 | Off air sparking at 4.5 mm. 1 coil prim. open | 6.0 " " " closed | 1.5 Signed: Francis J Allen. This Sheet must be filed on completion of the work. | ||