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).
Desired modifications for the Wraith Ignition coil.
| Identifier | ExFiles\Box 164\5\ img284 | |
| Date | 27th May 1937 | |
| 6017. To By/RD. Rm{William Robotham - Chief Engineer}/Wst.8/JH.27.5.37. Re Wraith Ignition coil to D.75673. In view of the benefits derived on exptl. test with the modifications below, we should like them included on the LOP. without delay. Unfortunately four coils have had to be scrapped as they were made inadvertently to the old LOP. which has not yet been superseded. The modifications desired are :- (a) Flexible connections on primary winding ends as well as secondary. (b) Primary end connections brought up through centre of the terminal screw and soldered over. (c) Secondary winding to consist of 15,000 turns of 42 S.W.G (d) Primary winding to be wound with D.C.C. superfine wire. (e) Large thackery spring washer under iron core to support. same against Vibration. Rm{William Robotham - Chief Engineer}/Wst. | ||