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 limitations and temperature tests for the Coshawk Ignition Coil.
| Identifier | ExFiles\Box 45\4\ Scan126 | |
| Date | 19th December 1922 | |
| To E.{Mr Elliott - Chief Engineer} from EFC. c. Ey. c. Ey/Ds. X4079a EFCl/T19.12.22. X.4079 - RE COSHAWK IGNITION COIL X3485 With reference to your EL/M8.12.22, we notice from LeC.1653 that the improved ignition coil does not allow either an increase in the diameter or the length of the coil. That, in order to provide a suitable air space and also room for the nutcracker spring between the secondary and the bakelite case, means that our windings are limited actually to something less than we have had, even in the previous standard Goshaw coil, and we query whether this is intended. By the time you receive this, R.{Sir Henry Royce} will have our report EFC2/T14.12.22 of the temperatures attained by the coil in the two positions, insulated and uninsulated, and we think it will be agreed that there is not sufficient reduction of temperature in the bracket position, even in the insulated case, to enable us to use a coil even of the same windings as previous standard, still less one in which the windings have to be reduced. X4079b As reported we have in addition to the improved bakelite encased coils with longer(but not larger) core, going through experimentally, a coil with both larger cross section and length of core and it may be better to push this coil through its experimental stage (which will be done very shortly now) before instructing a further coil to LeC.1653. Contd. | ||