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).
Creation of an ignition timing diagram for the Phantom engine, detailing magneto and battery advance curves.
| Identifier | WestWitteringFiles\S\September1928-October1928\ Scan116 | |
| Date | 12th October 1928 | |
| To R.{Sir Henry Royce} from EFC. c. RJ. E.{Mr Elliott - Chief Engineer} EY. EFC/T2/12.10.28. PHANTOM IGNITION TIMING. X8680 X928 We have drawn out for convenience of reference an ignition timing diagram, based upon your RL/ML9.9.28, of which the attached is a blueprint copy. The ignition lever travel is measured horizontally and degrees of advance reckoned on the engine are measured vertically. It is assumed, through this is not probably actually quite true, that the degrees of magneto advance correspond to the degrees of ignition lever advance proportionally. Therefore, the line of magneto advance is shown straight. The first half of the battery ignition advance is shown as a curve of arbitrary shape, and for the second half of the advance, coinciding exactly with the magneto line. Both curves are drawn both for full auto retard and full auto advance, the amount of which, e.g. 25°, is represented by the vertical distance between corresponding points of the similar curves. For your further convenience we have drawn on in pencil a similar representation of the present standard timing as obtained from the drawings, so that a practical comparison is exhibited. It appears that it might be worth while to have a diagram in which the curves represent the actual result given by the linkages, either finding this by taking a number of positions on paper, or observing it on an actual linkage. With the Watford EW6 magnetos as now received, there is no difficulty in firing with the slow speed running of the engine considerably less than 200 r.p.m. in the fully Contd. | ||