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).
Test results for maximum spark gap lengths and the effects of shorting gaps on E.O.6c and ELO.6 magnetos.
| Identifier | WestWitteringFiles\I\July1922\ Scan128 | |
| Date | 31th July 1922 | |
| Contd. -10- EFC1/T31.7.22. At all speeds above 1500 R.P.M., with timing lever advanced, shorting any one gap extinguishes the spark immediately following. At central and retard the effect is not so decided, and those sparks on one side appear to be more affected than those on the other. Normally the sparks all appear the same. The maximum regular spark gap lengths for all speeds over 1500 R.P.M. were, for the E.O.6c magneto:- Advanced 3.5 mm. Central 4.8 mm. Retard 5.3 mm. The results of shorting each gap while varying the speed were :- Advanced - spark following shorted gap extinguished at 1500 R.P.M. Central - Alternate sparks only extinguished, as above, Retarded - Alternate sparks only extinguished, as above, at 1800 R.P.M. but all sparks affected at 2500 R.P.M. The sparks otherwise appeared equal. On the ELO.6 machine the maximum regular spark gap lengths for all speeds over 1500 R.P.M. were :- Advanced 5.3 mm. Central 6.5 mm. Retarded 7.75 mm. Each gap shorted in turn while varying the speed :- Advanced - sparks following shorted gap slightly affected at 3400 R.P.M. Central - Sparks unaffected. Retarded - Sparks unaffected. Sparks from both sides normally appeared equal. Contd. | ||