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).
Testing and performance of Bosch magnetos for the 20 HP chassis.
| Identifier | ExFiles\Box 57\2\ Scan188 | |
| Date | 13th December 1927 | |
| To R.{Sir Henry Royce} from EFC. c. BJ. E.{Mr Elliott - Chief Engineer} c. EY. Wor.{Arthur Wormald - General Works Manager} X5790 EFCl/T13.12.27. BOSCH MAGNETOS FOR CHASSIS. X.5791 B R6/M2.12.27. A prolonged test of this Bosch magneto with jump spark distributor will be made if E.{Mr Elliott - Chief Engineer} will kindly return this machine at his convenience. We are putting out an enquiry as to whether the Bosch people make a suitable magneto for the 20 HP., i.e. with a moderate range of advance, but without a distributor. We agree as to the advantage of a sleeveless magneto from the point of view of cost, though technically speaking, as suggested in our EFC5/T8.3.27, there appears to be a very good case for the use of the sleeve machine in the particular circumstances of the 20 HP. The magneto must necessarily have a particularly good low speed performance in the retarded position, and this is just what can be got by the correct use of a sleeve, especially as at the same time it need not have a good high speed performance. Where a sleeve is not used there is very little to be gained in the magneto performance generally by attempting to move the range as a whole, so that the advance high speed performance is as high in speed or higher than the retard. That is to say, it will invariably be the case that where the best retarded low speed performance is obtained, the advance low speed performance must necessarily be still better. The fact, however, of reducing the range progressively will give a better and better low speed performance. Contd. | ||