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).
The high-speed sparking characteristics of R.Bosch and U.S.A. Bosch Z.R.6 magnetos.
| Identifier | WestWitteringFiles\F\February1921\ Scan84 | |
| Date | 3rd February 1921 guessed | |
| Contd. -9- EPC4/T3.2.21. advanced position, as above. This will not penalize on low speed retarded running a magneto which is given a large range by the makers. Results for such a comparison taken on the above magnetos will be given later, and subsequent magnetos will be compared in this way in preference to comparison on the makers range. (15) High Speed Sparking Characteristics. R.Bosch Z.R.6. Regular sparking at all speeds up to 3500 R.P.M. and positions of control lever on 7.0 mm. gaps. Slight flashing at the contact breaker on retard. Regular sparking on 7.5 mm. gaps at speeds from 1500 to 3000 R.P.M. in advanced position, with occasional missing at central and retard. Also sparking at contact breaker at retard and central which increases to flashing as speed rises. Sparking occurs at H.T. collector brush on slip ring at high speeds. Shorting any one gap extinguishes the spark immediately following, at high speeds at any degree of advance. U.S.A.Bosch Z.R.6. At all speeds on 7.5 mm. gaps sparking is regular with lever advanced, but missing occurs as lever is retarded. At 1500 R.P.M. with lever advanced, shorting extinguishes any one gap immediately following, but with lever retarded this effect is lessened. At 1900 R.P.M. the effect is the same with advance or retard. At 3100 R.P.M. regular firing ceases at all degrees of advance on 7.5 mm. gaps. It will be noted that the high speed operation is Contd. | ||