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 control range and subsequent test results on a low compression airship engine.
| Identifier | ExFiles\Box 37\3\ scan 016 | |
| Date | 27th October 1917 | |
| To R.{Sir Henry Royce} from EH.Da.{Bernard Day - Chassis Design} c. to BJ. " " E.{Mr Elliott - Chief Engineer} " " By.{R.W. Bailey - Chief Engineer} EH. EFC. X3191 Dal/CB27.10.17 X2038 X.3179. - BATTERY IGNITION. X.3191 X3199 X2814 With reference to Mr. Hives' memo EH1/LG181017, there is a slight misunderstanding. When the automatic advance was removed the range of control was increased to 46º (on crankshaft) by filing out slots. It is very easy to get this too much, and we are reducing it to 38º. This is being done because it is considered there is danger of firing the cylinder ahead, when the ignition is fully retarded even though the distributor segment is much nearer the correct cylinder point, thus - [Diagram showing a component with a dotted line indicating a path] believed to be dangerous It is desired not to retard beyond the position shown dotted. With the range of 38º now proposed, we were able this afternoon, on a low compression airship engine, with magneto and battery ignition set 30º BDC. fully advanced, and battery ignition retarded to 8º ADC, to start every time easily, to run steadily at 200 R.P.M. on battery, and to obtain 276 HP., on magnetos, 278.5 HP. on battery, and 283 HP. 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 (Contd). | ||