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).
Notes on six-cylinder magneto requirements for the 40/50 car, focusing on automatic advance mechanisms.
Identifier | ExFiles\Box 4\5\ 05-page276 | |
Date | 29th May 1924 | |
NOTES RE SIX-CYLINDER MAGNETO REQUIREMENTS FOR R.H. 40/50 CAR. One of the principal points of difference between the magneto now required and most magnetos which have been so far made, is that an automatic advance is required. As regards the details of the required degrees and speeds of the automatic advance, it is not considered at all likely that the figures given in the tentative specification will need to be materially altered. They can therefore fairly safely be taken as a basis upon which to begin to scheme an automatic advance. Our views with reference to the two alternative positions of the automatic advance mechanism, namely:- (1) That in which the advance is applicable to the whole magneto, the advance mechanism being made either as a separate unit, or built up upon the driving end of the magneto, and (2) That in which the automatic advance only advances the contact breaker and distributor, in which case it will probably be built into the magneto, at any rate if the magneto is of the revolving magnet type, which we think it might well be (see later), are as follows :- If the whole magneto is subject to automatic advance, the driving power for the magneto must pass through the automatic advance unit, which unit must therefore be subject to the impulsive kicks of torque. On the other hand there is the advantage that the advance (the automatic part at any rate) does not vary the internal time functioning of the magneto, thus rendering it possible to use a more ordinary type of design (of magneto). We are of the opinion, however, that the second method of automatic advance, in which the automatic advance mechanism only has to transmit a very light power with no impulsive torque kicks, is preferable, because there are various known methods of suitably overcoming the variations of the time functioning of the magneto consequent upon this method of advance. (In any case the hand portion of the advance will vary the time functioning of the magneto unless some such scheme is adopted.) Contd. | ||