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).
Experimental specification for 'B' type coils for battery ignition on the 'Goshawk' 11 engine.
| Identifier | ExFiles\Box 45\4\ Scan005 | |
| Date | 1st January 1922 | |
| X. 4079a BY/WER2/EF16. 1. 22. STAMP: RECEIVED HANDWRITTEN: RHO. C. to Sft.{Mr Swift} II B.Sc. W.S. H.S. BROCK. JAN 18 1922 STAMP: EXPERIMENTAL X. 4079 "GOSHAWK" 11. COIL FOR BATTERY IGNITION. "B" TYPE COILS. Kindly note that in accordance with EPC2/T9. 1. 22 it is desired that six of the above type of Ignition Coils should be made up for experimental use on "Goshawk" 11. The primary winding should consist of six layers of No. 20 S.W.G. D.S.C. - H.C. Copper wire total number of turns 300±10. It is desired that the primary winding should be wound as near as possible to 300 turns, this will probably mean that the last two or three layers will be somewhat loosely wound. We think it would be well to insert a little insulation between each layer of the primary winding and we suggest one layer .001 x 2.1/16-20 wide linen or paper. We estimate that the overall diameter of the primary winding will be increased by approximately .062. The secondary winding should consist of as many turns of the 40/50 Ignition Coil gauge of wire i.e.( 42 S.W.G. .004 enamel coated wire) as it is practicable to wind on, if possible 21.000±500. These Coils can be made to I.O.P. D.50210 less the 5½ ozs of 21 S.W.G. D.S.C. Copper wire for the primary winding which is called for in the Stock Parts Column of the I.O.P. This should be replaced by the following:- 20 S.W.G. D.S.C. copper wire - 26 yds, weight = 5½ ozs. BY/WER. WSR. | ||