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).
Graph showing the variation of make-ratio against speed for a double breaker ignition distributor.
| Identifier | ExFiles\Box 163\7\ img232 | |
| Date | 22th February 1935 | |
| R.R. DOUBLE BREAKER IGNITION DISTRIBUTOR, TO L.E.C. 3323 USING CAM TO D.B. 358, CURVE SHEWING VARIATION OF, MAKE-RATIO WITH SPEED, .020" GAP AT CONTACTS, MAKE-RATIO, DISTRIBUTOR SPEED (R.P.M.), FD{Frank Dodd - Bodies}/46, 22.2.35 | ||