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).
Suggestion for the instruction book regarding the M. Series 4 1/4 litre gearbox and gear changing.
| Identifier | ExFiles\Box 86\4\ scan0164 | |
| Date | 23th March 1938 | |
| 228. To NW.{N. Walker - Patents} from Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} c. By.{R.W. Bailey - Chief Engineer} Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}2/AP.23.3.38 BENTLEY M.{Mr Moon / Mr Moore} Series. Gearbox. We suggest for the Instruction Book: Brief description of 4 1/4 litre. Gearbox Four forward speeds and reverse; the highest forward speed being an overdrive or geared up indirect fourth speed. R.H. control. Overall Ratios:- 1st 10.25 2nd 6.43 Direct 4.30 Overdrive 3.64 Page.23 Gear changing. The gearbox ratios provide instead of the usual arrangement a direct 3rd. and overdrive fourth speed. Synchromesh of the 'positive' type is provided to facilitate engagement of these two gears. On the level 2nd. speed can be used for a standing start. It is recommended that in towns and under slow conditions direct gear should be used but that when the conditions permit faster driving overdrive should be used when quieter running and a better petrol consumption will be realised. No advantage will be obtained by using direct drive above 3800 r.p.m. The positions of the gears in the gate are as shown in the sketch. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} | ||