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).
Specification for a three-position ignition switch for the 40/50 and 20.HP models.
| Identifier | WestWitteringFiles\J\January1923\ Scan71 | |
| Date | 13th January 1923 | |
| TO Mr. STENT. FROM R.{Sir Henry Royce} c. to Mr. H.E. [Struck through] c. to Mr. H.S. [Struck through] ORIGINAL RECEIVED JAN 18 X1413 R4/M13.1.23. A switch is wanted for the 40/50, and sometimes the 20.HP. - small but very reliable, having three positions, to be fitted to board without disconnecting the wires, i.e. from the back. (1) { (a) Earth magneto in parallel with locked switch box. (b) Make through connection for battery ignition - primary circuit. } Battery only. (2) { (a) Break magneto earth circuit) (b) Continue to make connection as in (1). } Both ignitions. (3) { (a) Continue to break magneto earth as in (2). (b) Break connection for battery ignition. } Magneto only. As this switch works in connection with the locked ignition switch, no other positions are needed or desired, i.e. one cannot accidentally cut off all ignitions, and therefore cause confusion. The design for this is Mr. Stent's work after other urgent things, such as gearbox for "Seagull", and clutch for "Seagull". R.{Sir Henry Royce} | ||