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).
To Mr. Brock requesting the winding of a coil to specification D.71919.
| Identifier | ExFiles\Box 69\1\ scan0182 | |
| Date | 2nd February 1929 | |
| To Mr. Brock. X.870 EFC/T2.2.29. Will you please wind us another coil to D.71919 with 20000 turn secondary and flat primary. We hand you herewith coil bobbin and case which can be used up on this job. O/N.54733. EFC. | ||