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).
Confirming the satisfactory use of 22 gauge coarser primary coils with double ballast resistances.
| Identifier | ExFiles\Box 69\1\ scan0101 | |
| Date | 8th June 1928 | |
| X8710 To EY. from EFC. c. BY/RD. EFC6/T8.6.28. RE USE OF 22 GAUGE COARSER PRIMARY COILS WITH DOUBLE BALLAST RESISTANCES. X8720 From extensive tests recently made on the road we are now in a position to confirm as satisfactory the use of the above combination on cars on production. EFC. | ||