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).
Various schemes and problems related to gearbox design.
| Identifier | WestWitteringFiles\V\October1930-February1931\ Scan002 | |
| Date | 1st October 1930 | |
| FROM R.{Sir Henry Royce} GEARBOX PROBLEM. Referring to the situation at the moment, we have in the hands of Derby the helical sideshaft and 3rd. gear controlled by jaw clutches, which can be modified to the Maybach type. This is what we could adapt quickly to our present box. Our second scheme, which has only just been modified to become thoroughly workable, consists of an epicyclic double top speed, a ratio of about 1 and .74, driving a 3 speed box - not two speed as formerly - in which the 2nd. gear is single helical with jaw clutches like the above mentioned 4 speed box. This 3 speed box is controlled by the side lever as is usual, the double top is controlled by vacuum, and the whole is a slight modification to the box we sent to Derby early last year, and which we stopped from being constructed because we thought it did not cover the requirements sufficiently thoroughly. We have now schemed the way mentioned above in which this same combination can be more easily controlled, and we have decided to make the double top by positive clutches instead of by friction. The modification we have lately added to this scheme is the use of a 3 speed box instead of a 2 speed box, and the 3 speed box having clutches instead of tooth corner engagement. We ought to have with this equipment a silent 2nd. 3rd. and top gear, an easy change 2nd. 3rd. and top gear, and, as it is all positive we have a combination which we believe has not been made before, and is superior to anything being offered. We are trying to get this made with breathless haste so that if possible it can replace No. 1. proposal because we believe it would be considered nearer perfection. The No. 3. scheme is a complete train of epicyclics with an epicyclic reverse, the control of these being by side lever only, having much the same characteristics as what is known as the synchronous mesh, but our synchronous mesh will be extended to all the gears except the reverse, and is much easier than the ordinary gears because our synchronising speed is when the epicyclic rings come to rest, which we have arranged to be accomplished by an oil operated brakes controlled by the side lever slider. This is the arrangement that we have been working on for several weeks, since we decided that perhaps our 4th. scheme is a (1) | ||