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 of the make ratio versus speed curve for a new standard contact breaker.
| Identifier | ExFiles\Box 35\6\ scan 433 | |
| Date | 27th July 1928 | |
| R.R. STANDARD BATTERY IGNITION. MAKE RATIO - SPEED CURVE OF NEW STANDARD CONTACT BREAKER to LEC 2460. MAKE RATIO .7 .6 .5 .4 .3 .2 .1 0 DISTRIBUTOR SPEED. r.p.m. 200 300 400 600 800 1000 1200 1400 1600 1800 H.E.W 27-7-28 | ||