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).
Experiment to build three improved battery ignition coils.
| Identifier | ExFiles\Box 45\4\ Scan184 | |
| Date | 26th July 1923 | |
| X4079 By/Ds1/ML26.7.23. To EFC. from By/Ds. c. RHC.{R. H. Coverley - Production Engineer} c. Sft.{Mr Swift}for Mr. Gamble. c. Hs.{Lord Ernest Hives - Chair} X.3445 - RE BATTERY IGNITION COIL. X.4079. In accordance with BM's instructions - BY5/P25.7.23., it is required to build experimental three ignition coils having two turns of oil paper - .001 thick between each layer of the primary winding to ensure more efficient insulation. In all other respects the coils are to be wound to Winding Drawing F.7186. As this will increase the overall diameter of the finished coils by .020 it may be necessary to reduce the number of turns of oil silk round the outside, sufficient to allow of the coil entering the case. Please put the above experiment in hand at once and inform D.O. of results. By/Ds. | ||