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).
Results of experimental bench tests on various Bosch magnetos.
| Identifier | WestWitteringFiles\F\February1921\ Scan76 | |
| Date | 3rd February 1921 | |
| To R.{Sir Henry Royce} from EFC. c. to CJ. c. to E.{Mr Elliott - Chief Engineer} c. to Bn.{W.O. Bentley / Mr Barrington} c. to PN.{Mr Northey} c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to Da.{Bernard Day - Chassis Design} c. to By.{R.W. Bailey - Chief Engineer} c. to EWT. for R.R. Inc. ORIGINAL. X.427 - R.{Sir Henry Royce} BOSCH Z.R.6 MAGNETO. X.2375 X.3916 - U.S.A. BOSCH Z.R.6 MAGNETO. X.4181 X.3917 - U.S.A. BOSCH B.6 MAGNETO. The following are the results of some experimental bench tests on the above magnetos :- X.1723 (1) The weight of the R.Bosch Z.R.6 magneto is 18.25 lbs. " " " U.S.A.Bosch Z.R.6 " " 15.1 lbs. " " " " " B.6 " " 11.0 lbs. (2) A comparison of the R.{Sir Henry Royce} Bosch Z.R.6 and U.S.A. Bosch Z.R.6 magnetos was made in Mr.Hives' report Hs{Lord Ernest Hives - Chair}3/LG20.7.20. The outstanding difference is in the distributor, the working surface being flat instead of cylindrical in the U.S.A. Bosch case, and no trouble on this account has been experienced on our bench tests. The R.{Sir Henry Royce} Bosch Z.R.6 has long cams, whereas the U.S.A. Bosch has short cams. The pole shoes of the R.Bosch appear to be extended in the direction of rotation, whereas in the U.S.A. Bosch they appear to be symmetrical. As regards noise, the R.{Sir Henry Royce} Bosch appears reasonable at the gears but quite bad at the contact breaker. The U.S.A. Bosch appears to give a noise on the bench composed of a knocking at the contact breaker and also a slight rattle in the gears. Oilways are provided in both machines. The R.Bosch has a mechanism which retains the cam ring in position when the Contd. H'K 332Y (100 L) (WH 188 10-18-20) C 3841 | ||