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).
Adjustments to the battery ignition timing range for an airship engine to prevent dangerous early firing.
| Identifier | ExFiles\Box 52\3\ Scan247 | |
| Date | 27th October 1917 | |
| To H... A. {Mr Adams} to D.I. By. {R.W. Bailey - Chief Engineer} [Redacted] KEC. X.2814 Dal/CB271017. 2 X 2038 - Re Battery Ignition. (Remy) X.2814 X.3191 X.3199 With reference to Mr Hives's memo RH {R. Hollingworth} /LG181017, there is a slight misunderstanding. When the automatic advance was removed the range of control was increased to 46° (on crankshaft), by filing out slots. It is very easy to get this too much, and we are reducing it to 38°. This is being done because it is considered there is danger of firing the Cylinder ahead, when the ignition is fully retarded even through the distributor segment is much nearer the correct cylinder point, thus. [Diagram showing a path with a dotted line boundary] Believed to be dangerous. It is desired not to retard beyond the position shewn dotted. With the range of 38° now proposed, we were able this afternoon on a low Compression airship engine with magneto and battery ignition set 30° BDC fully advanced, and battery ignition retarded to 8° ADC, to start every time easily, to run steadily at 200 R.P.M. on battery, and to obtain 276 H.P. on magnetos 278.5 H.P. on battery, and 283 H.P. on both ignitions, at 1600 R.P.M. To do this we used KLG plugs on battery, with .025 gap. We found Lodge plugs with less than .008 gap on one side used on magneto. We had one back-fire, believed to be an induced spark across one of these small gaps, as no other explanation could be found. H.R. 233a (500) (T) (S.D. 408. 26-4-17) Bm. 2/156/13. | ||