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 magneto sparking speeds at different advance and retard settings with and without a standard leak.
| Identifier | ExFiles\Box 65\3\ scan0230 | |
| Date | 8th December 1924 | |
| (2) which it passed OK. The std leak and test gap was then used and the low speed figures with and without the leak were as follows:- Minimum speed for regular sparking on 5.5mm gaps in air. advance 60 rpm retard 170 rpm with the std 2.5 micromho leak and std test gap the retarded figure was 350 rpm. Our production specification limits for low speed performance are :- advance 120 rpm } on 5.5 mm gaps in air retard 190 rpm } We then obtained a std E06 magneto No. 98251. which the test dept assured us was quite OK and tested it similarly. Signed (contd) | ||