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 low sparking speeds of an experimental magneto with a sloping base.
| Identifier | ExFiles\Box 40\5\ Scan019 | |
| Date | 8th May 1921 | |
| X 3630 8.5.21. X.3630. MAGNETO WITH SLOPING BASE. The low sparking speeds are as follows :- Expl. Magneto. Magneto without strap. Magneto with strap. No.40886, (a) 195 r.p.m. (a) 200 r.p.m. (b) 268 r.p.m. (b) 295 r.p.m. (c) 302 r.p.m. (c) 330 r.p.m. C.A.P R.R. 2886 100(T) 69 H'S 77-7-20 O 2169 | ||