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 sheet for the Phantom II epicyclic gearbox detailing various gear ratios.
| Identifier | ExFiles\Box 15\5\ Scan237 | |
| Date | 29th January 1932 guessed | |
| (1) P.II EPICYCLIC GEAR BOX. Epicyclic Gear Solid (i.e. in Top Gear. Revs of Prop Shaft per rev of engine. | 3rd Speed. | 2nd Speed. | 1st Speed. | Reverse. | |---|---|---|---| | Direct. | .663 | .377 | .303 | Revs of engine per rev of 3rd motion shaft | 3rd Speed. | 2nd Speed. | 1st Speed. | Reverse. | |---|---|---|---| | Direct | 1.51 | 2.655 | 3.29 | Revs of engine per rev of road wheel (11/41 Axle) | 3rd Speed. | 2nd Speed. | 1st Speed. | Reverse. | |---|---|---|---| | 3.727 | 5.61 | 9.86 | 12.29 | (2) EPICYCLIC REDUCTION .745: 1 (i.e. in 3rd Gear on column control.) Revs of Prop Shaft per revs of engine. | 3rd Speed. | 2nd Speed. | 1st Speed. | Reverse. | |---|---|---|---| | .745 | .494 | .281 | .225 | Revs of engine per rev : of 3rd Motion Shaft. | 3rd Speed. | 2nd Speed. | 1st Speed. | Reverse. | |---|---|---|---| | 1.341 | 2.02 | 3.56 | 4.43 | Revs of engine per rev: of road wheel (11/41 axle) | 3rd Speed. | 2nd Speed. | 1st Speed. | Reverse. | |---|---|---|---| | 5.0 | 7.53 | 13.25 | 16.5 | | ||