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).
Interconnection of magneto and battery controls for air-ship engines.
| Identifier | ExFiles\Box 52\3\ Scan244 | |
| Date | 18th October 1917 | |
| R.R. 238 A (770 H) (S.D). 447 9-5-17) G 1865. X.2814 To R. {Sir Henry Royce} from EH. Copy to BJ. " " E. {Mr Elliott - Chief Engineer} " " Ey. Ehl/LG18.10.17. 18th Oct. 1917. X2038 Re - Inter-connection of Magneto & Battery Controls. X 3173 X 3191 X 3199 X 2026 On the Air-ship engines the control of the battery ignition and the magnetos are not inter-connected. It was the Admiralty's wish that they should be seperate. X.2814. On the Remy ignition on the air-ship engines they cut out the automatic advance which gave 10º range but have not increased the hand control to make for this. They have had trouble because of having insufficient range. The range is 27º to 28º, very little more than the magneto. To obtain the full power with the Remy with this range it is necessary to get it to fire retarded the same position as the magneto 10º B.D.P. with this setting the engine back fires when starting and is not nearly as good for slow running. We reckon we want at least 50º range on the battery so that it will fire 35º B.D.P. advanced and 15º A.D.P. retarded. X.3161. X.3174. With reference to the query at what speed we can start off the main magneto, when we were making tests with the electrical starter on the Eagle we tried to see if we could start off the main magnetos, we found we could not do so, when the engine was cold we were running it at 28 to 30 r.p.m. with a hot engine we could occasionally get a start turning at 30 to 35 r.p.m. To be certain of starting under all conditions and allow for variation in magnetos we should estimate the engine should be turned at 40 to 45 r.p.m. EH. | ||