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).
The ballast resistance wire for the 'Goshawk' battery ignition system.
| Identifier | ExFiles\Box 54\5\ Scan155 | |
| Date | 14th July 1921 | |
| To R. {Sir Henry Royce} from EFC. {E. Fowler Clarke - Electrical Engineer} c. to AJ. c. to E. {Mr Elliott - Chief Engineer} c. to Da. {Bernard Day - Chassis Design} c. to By. {R.W. Bailey - Chief Engineer} c. to Ey/WER. c. to Da {Bernard Day - Chassis Design} /Thr. X3485 EFC {E. Fowler Clarke - Electrical Engineer} 4/T14.7.21. X.3485 - "GOSHAWK" BATTERY IGNITION X.3716. Referring to LeC.1410 - Ballast Resistance for Goshawk Ignition, it has been pointed out to me by By's Dept. that it is impossible to get the standard length and gauge of ballast resistance wire on this resistance, but only to get 31 1/2" in place of 50" of No.34 1/2 S.W.G., which is our standard. It will be remembered that it was agreed to arrange the ballast resistance in the first instance to be a comparatively large proportion of the total resistance of the circuit - this we look upon as desirable. Experimentally on the bench we find the current consumption to be increased 25%, whereas we do not find any advantage in the sparking characteristics of the ignition by reducing the length of ballast. If anything, a disadvantage appears of increased sparking at the contact points. Although we are allowing this ballast resistance wire to go through (at the moment) to be tried experimentally on the Goshawk, we do not think it will be as satisfactory as the present standard, and we recommend that steps should be taken to provide for the length of ballast which we know by experience is satisfactory. It has been noted experimentally that if the voltage of the battery be reduced to 8 so that the running | ||