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).
Graph comparing the performance of various chassis ignition coils, plotting secondary kilo volts against sparks per second.
| Identifier | ExFiles\Box 164\5\ img324 | |
| Date | 1st June 1937 | |
| COMPARISON OF CHASSIS IGNITION COILS L6 - LUCAS COIL IN RR TYPE CASE LTB12 - LUCAS COIL IN METAL CASE N1 - RR. COIL TO D.75573 UNFILLED N3 - SAME AS N1 BUT IMPREGNATED & FILLED WITH BITUMEN COMPOUND FAULTY COIL - FAILURE DUE TO FRICTION BETWEEN PRIMARY & SECY. CONNECTION & INSULATING TUBE CAUSING SECY. WIRE TO FRACTURE. Y-AXIS: SECONDARY KILO VOLTS X-AXIS: SPARKS/SEC CURVE LABELS: N1, L6, N3, LTB12, FAULTY COIL | ||