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).
Battery ignition systems, specifically regarding the performance of different contact breaker lever springs.
| Identifier | WestWitteringFiles\Q\2April1927-June1927\ 50 | |
| Date | 25th April 1927 | |
| To R.{Sir Henry Royce} from EFC. ~~c. EJ. PN.{Mr Northey}~~ ~~c. Ey. De.~~ ~~c. Ev.{Ivan Evernden - coachwork} Wor.{Arthur Wormald - General Works Manager}~~ ORIGINAL EFC3/T25. 4. 27. BATTERY IGNITION. Further to our EFC1/T1.4.27 in which it was stated that since our previous report we had received standard shape contact breaker lever springs giving approximately 50% bigger pressure on contact points, and that this single variation would be tried out experimentally on the ~~battery~~ bench for comparing with other results. We have now^had^ three different lots of stronger springs, none of which have been satisfactory. It appears that greater strength ^in^~~than~~ the present design of spring cannot be obtained without unduly increasing the stress and reaction on the pivot. Please find attached copy of my assistant's report WC.11 in this connection. The idea of running stronger springs is mainly for a possible improvement of platinum or tungsten point performance, because as shewn up by the results issued under cover of our EFC1/T1.4.27, increased strength of spring was not necessary from the bouncing point of view. A point which we have referred to once or twice is the fact that in the RR. contact breaker the design is not such that the average force exerted by the spring on the lever opposes nearly exactly the average force exerted either by the cam or the fixed contact point on the lever, so that there is a big reaction on the pivot. | ||