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).
Impregnation of ignition coils with bitumen compound and their attached output curves.
| Identifier | ExFiles\Box 164\5\ img315 | |
| Date | 26th October 1937 | |
| -2- Rm{William Robotham - Chief Engineer}/RC.{R. Childs}5/MH.{M. Huckerby}26.10.37. To D75673 ignition coils be impregnated with bitumen compound. Output curves of the above coils are attached. Rm{William Robotham - Chief Engineer}/RC.{R. Childs} | ||