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 performance of a double breaker ignition distributor and ongoing associated coil tests.
| Identifier | ExFiles\Box 163\7\ img231 | |
| Date | 28th December 1933 | |
| -2- Hs{Lord Ernest Hives - Chair}/Wst.3/MA.28.12.33. Cont'd.{John DeLooze - Company Secretary} (2) Our own double breaker ignition distributor fitted with the new cam to drawing DB.{Donald Bastow - Suspensions}358. It will be noticed from these curves that the make ratio which is a determining factor for high speed operation remains practically constant up to a distributor speed of 3,200 which is equivalent to an engine speed of 6,400, and even at 10,000 R.P.M. engine speed the make ratio has only fallen to the value we at present set our standard 20/25 distributor, i.e. .55. This improvement in performance is also brought about by the fact that the contact breaker levers on the double breaker distributor are appreciably lighter than the Bensport. We are carrying out further tests with the ignition coil using various values of ballast resistance and different windings to improve the coil performance at high speed. These developments are extremely important in view of the fact that the SpectreCodename for Phantom III we shall /on require from each ignition distributor, and therefore from each ignition coil, twice as many sparks per second as that required by the Bensport at any speed. Hs{Lord Ernest Hives - Chair}/Wst. | ||