Technical note outlining two methods for implementing an overdrive in the Wraith gearbox.
| Identifier | ExFiles\Box 8\11\ 11-page105 | |
| Date | 31th December 1937 | |
| FILES 628 To get an overdrive in Wraith Gearbox. (a) 3rd. speed becomes overdrive. (1) Assuming Bentley type cone attachment on overdrive gear the pitch radius of this pair cannot be less than 1.462. Ratio of this pair 1.462 / (3.2 - 1.462) = 1 / 1.19 (2) C.M. ratio must be 1:1 (3) Highest poss. 1st. speed 2.38 or 15/36. (4) Shaft centres must be increased for 36 tooth wheel. (5) Reverse shaft must be moved out of way of overdrive 2nd. motion shaft gear. (6) Overdrive gears must move .150 backwards necessitating alteration to central diaphragm. (b) 2nd. speed becomes overdrive. (1) No difficulty about ratios without increasing shaft centres. (2) Very complicated actuation must be designed having necessary pick-up devices probably necessitating mods to casting. Rm {William Robotham - Chief Engineer} /Gry. {Shadwell Grylls} | ||
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).