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).
Design, costs, and feasibility of a new gearbox, comparing it to the Wraith box.
| Identifier | ExFiles\Box 136\2\ scan0013 | |
| Date | 23th January 1939 guessed | |
| - 2 - should not be made as quiet as those of previous boxes. They have the same helix angle and pitch, and we cannot detect that the removal of the centre bearing from the side shaft affects the problem. We put in a steady bearing, but it made no difference. Before, therefore, it is said that it is not practicable to get third and second quiet we should like these gears to have the same chance in manufacture as the production Wraith. At the moment there is no rig for running them together before they are put in the box. As originally designed, first gear is not helical. We now accept that if we got away with this feature on B.V., it might not do for Wraith replacement, and so a helical bottom has been schemed into the box. It has been done with very little additional complication. The first sample should be running in less than three weeks. With regard to its other virtues, this box is lighter than that of the Wraith, is £25 cheaper and permits of 2" lower front seat. Wraith box in B.V. One naturally hopes that the Wraith box will be a safety first measure when fitted in an experimental B.V. It is necessary to remember, however:- (1) It has never been made or run as an overdrive. It will not be on the road in a B.V. until Feb.5th. (2) Making it suitable for an overdrive has added to its cost which is already formidable. (3) The fact that it is quiet in a Wraith chassis does not necessarily guarantee the same degree of silence in a rationalised frame. (4) It could not justifiably be perpetuated as at present being fitted up as the servo is on the wrong side and necessitates two additional countershafts (see sketch). (5) Its cost, without the overdrive is £ (6) It has the undesirable feature of raising the seating position 2", and, consequently requires modified column position. (7) To get the servo in the position where it will ultimately have to go requires an almost complete re-design of the box. | ||