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).
Design flaws and failures of a Splitdorf magneto's distributor rotor.
| Identifier | WestWitteringFiles\R\2December1927-February1928\ Scan090 | |
| Date | 23th December 1927 | |
| To R.{Sir Henry Royce} from EFC. c. BJ. E.{Mr Elliott - Chief Engineer} c. Da.{Bernard Day - Chassis Design} Wor.{Arthur Wormald - General Works Manager} c. Rg.{Mr Rowledge} By.{R.W. Bailey - Chief Engineer} ORIGINAL EFC1/T23.12.27. SPLITDORF MAGNETOS. (Further to our EFC3/T22.12.27). The worst feature of the design of this machine is the jump spark distributor, and particularly the distributor rotor. Examination of one of the rotors shews this to be distorted in such a way that the sparking points would not be running round in the same plane as originally. There are also two cracks in the material which might ultimately lead to complete failure. Again, there is considerable marking on the back face of the revolving rotor disc which runs just over the heads of the screws which secure the H.T. wires. It may be remembered that we reported previously that in order to secure the H.T. distributing wires to the magneto the rotor had to be removed. Then, if the heads of the screws are not screwed down so as to sink below the level of the insulating material in which the heads are sunk, i.e. if one head should stand proud, it would foul the rotor as suggested in our report WC.56. From marks on the rotor it has been clearly the case that this same rotor has been rubbing on the head of one of these screws, a circumstance which may have been assisted by the distortion of the rotor. On further inspection, we find that the insulation of the central H.T. brush holder has nearly completely failed by tracking in such a way that the magneto, in the condition as received from the engine, is capable only of very weak sparking, i.e. on short lengths of gaps. When the gaps are opened out, sparking takes Contd. | ||