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 an experimental tunnel, focusing on cobalt magnets and extended pole shoes.
| Identifier | ExFiles\Box 57\2\ Scan220 | |
| Date | 17th January 1929 guessed | |
| TESTS ON EXPERIMENTAL TUNNEL. COBALT MAGNETS. EXTENDED POLE SHOES. LEAK. R.R. GAP 400,000 Ohms. 800 R.P.M. Retard and up to 5,000 R.P.M. 1,400 R.P.M. Advance ditto LOW SPEED. 60 Advance 120 Retard 5½ m/m 3 pt. Gap. 45° * The experimental magneto had a cam cage limited to 45° LOW SPEED. On 6ft. Braided Cable 10,000 voltage ball gaps. 120 Advance. 240 Retard. | ||