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).
Improving the performance of a Watford E06 magneto by modifying its cams.
| Identifier | ExFiles\Box 48\2\ Scan413 | |
| Date | 29th March 1926 | |
| EFC {E. Fowler Clarke - Electrical Engineer} 1/T29.3.26. -7- Contd. correct on principle, we are also giving a similar diagram of Watford E06 magneto No.73972 from actual observation. In these diagrams only two segments of the distributor are shown so that the brush may be supposed to be revolving at the same speed as the armature, this being quite an accurate representation of comparative purposes. This diagram shows that the backward overlap at retard of the Watford magneto is unnecessarily large, and in fact it would be possible with the timing as it stands, to use a considerably smaller distributor, or with the distributor as it is, to use longer cams. We wish it to be understood that our arguments and results are mainly on principle and we agree that they may require some small adjustments as a result of tests, some of which tests we are hoping ourselves to make to confirm our points. In the main, however, we are, as previously stated, of the opinion that the general performance of the magneto could be materially improved without loss of in any direction, and in particular we consider that improvement would result in running qualities, noise, etc., by the use of cams giving a make period of 100° or perhaps 110° or even 115° only, instead of the approximate 150° as at present. The cams should be so arranged to give a break which does not vary more than ± 3° for a variation of ± .004" in the platinum point gap, but the make edge of the cam should be arranged with a much gentler slope to the extent Contd. | ||