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).
Ignition options for a six-cylinder engine with an 'interlaced' crank.
| Identifier | ExFiles\Box 54\5\ Scan347 | |
| Date | 8th December 1930 | |
| X5680. Ry. from EFC. c. E.{Mr Elliott - Chief Engineer} c. Ry/SS.{S. Smith} EFC2/AM.8.12.30. X.5680. SIX CYLINDER ENGINE WITH "INTERLACED" CRANK. Answering your Ry12/Cl2.12.30 electrically speaking the 30° interval would be just sufficient. The break and make periods would have to be approximately 6° and 24°. This however, though suitable electrically, would be complicated mechanically and could not be suitably done with one cam and one breaker. It would be possible to use a half cam and two breakers, the half cam comprising a semi-circle and semi-hexagon and the breakers being set with their rubbing blocks at 150° and 210° apart. We have, however, two suggestions to make one of which (either) we think you will be inclined to adopt. They are as follows :- (a) This suggestion is to use a 12 cylinder magneto utilising the distributor points 1, 3, 5, 6, 8 and 10 after having earthed the remainder 2, 4, 7, 9, 11 and 12. (b) The other suggestion is to utilise both the present ignitions i.e. magneto and battery, having set the drive of the magneto and arranged the interconnection of combined advance control in such a way that there are available from the two ignitions 12 sparks equally placed in time. Those not required for firing purposes would be taken to earth in accordance with the scheme of numbers given in (a) above. EFC. | ||