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).
Production viability of the B.50 gearbox for the 'M' series Bentley, outlining untested features.
| Identifier | ExFiles\Box 99\4\ scan0284 | |
| Date | 10th March 1939 | |
| H28 BY [crossed out] c. Rm.{William Robotham - Chief Engineer} Da{Bernard Day - Chassis Design}/Hdy.{William Hardy}3/G.10.3.39. B.50 GEARBOX, SERVO AND DAMPER CONTROL FOR USE ON B.5. With reference to the question whether it is safe to proceed with this box for production, to follow immediately on 'M' series Bentley, it is difficult to give a positive answer in view of the new features still untried, but as set out below, the position seems sufficiently free from serious risk to justify this course in view of the objections to the other available courses. The position appears to me to be as follows :- Silence of overdrive, 2nd and 1st speed gears already satisfactory as regards the box. It is reasonable to count on further improvement with modified mounting of the propeller shaft intermediate bearing and increased experience in grinding the gears. Features of which we still have little or no experience are :- (1). Whether 1st, 2nd or reverse stay in mesh. (2). Whether the double thrust load now placed on the rear end thrust washer on the layshaft when in reverse will be too much for the area available. (3). Durability and silence of the twin row square roller bearings to replace the needle rollers on the layshaft. (4). Durability of the larger ball bearings for the actuating forks. Strength of the larger shaft. Durability of the bearing surfaces of the forks. (5). Whether reverse will be sufficiently silent. I do not think that any of the above will cause serious trouble. Of the gears which may work out of mesh, reverse is the only one which we have reason to have any doubt about. We should have some positive information about this by next Wednesday, when it is expected that a reverse of the new type will be on test. | ||