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).
Schematic diagrams of two proposed gearbox designs, one with gear ratios and selector positions.
| Identifier | ExFiles\Box 15\5\ Scan250 | |
| Date | 7th March 1932 guessed | |
| Fig II ENGINE PROP SHAFT 1ST 2ND 3RD C M NO GEARS TURNING WITH ENGINE IDLING Fig I ENGINE PROP SHAFT 41 19 27 33 35 25 A B C X Y TOP 1:1 X TO RIGHT Y TO LEFT 3RD BC 1.3:1 " RIGHT 2ND AB 2.0:1 LEFT LEFT 1ST AC 3.0:1 LEFT RIGHT ALL SILENT GEARS. WITH 3 CONSTANT MESH PINIONS | ||