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).
Comparison of spark length vs. cable length for a standard R.R. ignition coil and a Remy 6-cylinder 6-volt ignition coil.
| Identifier | ExFiles\Box 52\3\ Scan352 | |
| Date | 9th April 1920 | |
| X.2814 EFC. {E. Fowler Clarke - Electrical Engineer} JA125/9.4.20. X.3129 X. X.3199 X.2814 SPARK LENGTH - CABLE LENGTH CURVES FOR STANDARD R.R. IGNITION COIL AND REMY 6 CYL. 6 VOLT IGNITION COIL. Rolls-Royce Coil. Cable length. .5' 1' 2' 3' 4' 6' 8' 10' 12' 14' 16' 18' 20'ft. Gap. .460 .455 .448 .440 .430 .420 .440 .425 .410 .370 .240 .200 " Remy 6 volt 6 cyl. coil. Cable length. .5' 1' 2' 3' 4' 6' 8' 10' 12' 14' 16' 18' 20' Gap. .460 .450 .450 .440 .430 .400 .430 .420 .400 .420 .390 .220 .180 " In comparison to the curve obtained 23/10/19. on another standard R.R. coil the present coil gives a much less rapid fall of maximum gap with increase of cable length. It was pointed out in reports of 23/10/19 and 8/11/19 that the somewhat inconsistent results obtained on the R.R. coil then tested may have been due to some intermittent internal discharge, perhaps on account of coil not being properly dry after impregnation. The curve obtained to-day shows a rapid fall in length of maximum gap, when the length of cable is about 15 ft. There is an indication that the steady fall in the maximum gap is arrested in the case of the R.R. coil, when the cable length is about 6 ft. There is also indication that the rapid fall of maximum gap, when the length of cable is about 15 feet. | ||