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 ignition on airship engines, raising concerns about timing and potential backfires.
| Identifier | ExFiles\Box 37\3\ scan 014 | |
| Date | 16th October 1917 | |
| X.3191 EH. from E.{Mr Elliott - Chief Engineer} c. to EY. West WitteringHenry Royce's home town. Oct.16th 1917. X.3199 X.3191 X.3173 X.2814. X.2038 - INTERCONNECTION OF MAGNETO & BATTERY IGNITION. E1/W161017. With further reference to my memo E5/W151017, to By.{R.W. Bailey - Chief Engineer}, copy to yourself, it would be interesting to know in what way you have coupled the magneto and battery ignition on the airship engines. You have already demonstrated that the Remy ignition will give a sufficient spark at the low speed obtained when the engine is turned by a hand starting gear with a reduction of 1 in 9. It will be seen that if the magneto and battery ignition are coupled synchronously and the most advanced point of firing is 30°, then owing to the restricted range of movement on the magneto cam casing the most retarded point of firing will be still advanced to the extent of 6° or 7°. In view of the battery ignition giving a sufficient spark to start the engine, this looks rather dangerous and one would think the natural result would be a back fire. Even if both ignitions are switched on we should not anticipate any trouble from the magneto at the slow starting speed, because we do not expect it to be sparking under these conditions. It would be further interesting to know/at what engine speed the magneto commences to be an effective ignition. Would you kindly let us know about the above two points as soon as possible. E.{Mr Elliott - Chief Engineer} | ||