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).
Design and advance mechanisms of Watford and Lucas magnetos.
| Identifier | ExFiles\Box 65\3\ scan0003 | |
| Date | 11th November 1926 | |
| EEC. Wd.{Mr Wood/Mr Whitehead} BY3/H5.11.26. WATFORD MAGNETOS. X.7791. X.8796. Referring to EFCl/LG3.11.26 and the information in R6/M2.11.26, the position in regard to magnetos is as follows :- 1. The Watford Company are not at the moment making, not have they made, a magneto on similar lines to the Lucas. They are acquainted with the general scheme, but since it involved a larger armature in addition to the extended pole shoes, they had not made any attempt to move in this direction, as they consider that their sleeve type magneto is more than the equivalent of this proposal. 2. The sleeveless magneto which R.{Sir Henry Royce} referred to I find from enquiry was a standard sleeveless type magneto fitted with an automatic advance mechanism arranged between the drive and the magneto in such a manner as to advance the magneto as a whole, under which circumstances of course the braking occurred under constant conditions, and therefore the magnitude or value of the sparking was unaltered in relation to the advance. 3. The Watford Company are quite prepared to consider producing to our requirements a magneto of the Lucas type provided that R.{Sir Henry Royce} prefers this proposal to the one outlined under Heading 2. in which a sleeveless magneto of a standard type is advanced as a whole in relation to the drive. 4. I am writing to R.{Sir Henry Royce} putting the facts of the case as I know them to be, before him, and asking whether he is interested in the Watford Company producing a sleeveless magneto capable of a large advance by our present methods or by hand, which would be made up with a big armature and extended pole shoes on the lines of the Lucas designs, or whether he was more interested in the use of a standard type sleeveless magneto driven through a mechanism for automatically advancing the magneto as a whole on its drive by means of an automatic advance mechanism. 5. The Watford Company have asked us to give them curves showing the advance characteristics we require in an automatic ignition. We have such a curve in the Experimental Dept. developed in connection with the relay advance mechanism at present used on the Phantom. A copy of this curve would, I think, meet Mr. North's requirements. BY.{R.W. Bailey - Chief Engineer} | ||