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).
Preliminary report on the American Bosch ZR6 magneto, comparing its weight and construction to the German and Watford versions.
| Identifier | WestWitteringFiles\E\July1920\ Scan22 | |
| Date | 20th July 1920 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to BN.{W.O. Bentley / Mr Barrington} c. to OY. c. to Na.{Mr Nadin} c. to E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} ORIGINAL X.3916. PRELIMINARY REPORT ON AMERICAN BOSCH MAGNETO ZR6. X 430. X 2375 Although this magneto is called ZR6 type, it is in many ways different to the German Bosch ZR6 Magneto, which we used on our cars before the war. The parts on this magneto are not interchangeable with the German Bosch ZR6. The weight of the Magneto is 15.5 lbs. " " " German ZR6 is - 18.4 lbs. " " " Watford is - 12.8 lbs. X.800 / X.1819 The American Bosch Magneto is of the same dimensions as the German ZR6 but as they use aluminium die castings instead of bronze, this accounts for the difference in weight. It is in the high tension distributor that this American Magneto differs chiefly from the German ZR6. A high tension carbon brush is fixed into an insulated holder to the large gear wheel. The distributor is formed by having a high tension collecting ring and six segments suitably formed in a stabilite moulding. The high tension carbon brush has sufficient surface so that it rubs on the collecting ring and makes contact with the different segments as it revolves. We see nothing against this form of high tension distributor, in fact, we think there should be less chance of pre-ignition with this form than with the usual ZR6 form. Any carbon dust which is formed has a chance of Contd. | ||