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).
Tree diagram of battery ignition systems and their corresponding coil numbers.
| Identifier | ExFiles\Box 37\1\ scan 074 | |
| Date | 29th June 1920 | |
| X 3199 29/6/20 TREE OF BATTERY IGNITION AND COIL NUMBERS. Battery Ignition (General) X.3199. R.R.trembler Ignition (Chassis) X.1520. R.R.non-trembler Ignition (chassis) X.3129. R.R.Non-trembler Ignition(aero) X.3173. Trembler coils (general) X.243 Non-trembler coils. (general) X.918. R.R.Trembler Coils. X.562. R.R.Non-trembler Coils X.3445. Handwritten text: Battery Ignition Ignition Coils X 3199 Bottom left corner text: R.R. 999. (250T) (SD670 19-7-17) A/P.1898S | ||