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).
Specifications and comparisons for gearbox components, particularly in relation to the Phantom III.
| Identifier | ExFiles\Box 8\11\ 11-page030 | |
| Date | 8th July 1936 guessed | |
| (sheet 2) An extension is provided at the rear end of the box to shorten the propeller shaft. A Gits oil seal is used at the rearmost bearing as oil cannot be prevented from running down the extension and submerging whatever seal is used, on a severe gradient. To help to avoid the top and 3rd speed gears working out of mesh the front compartment is longer than is proportional to Phantom III. This has enabled a fork to be used for the reverse actuation. The bushes for the 3rd and 2nd speed gears should be pressed in and hardened steel washers used for endwise location as recently instructed for trial on Phantom III. The 2nd speed sliding piece is shown as for the standard Phantom III, but whether this will be required like this ultimately, depends upon experiments now being made on Phantom III. As the casing is not being split at the centre division, the layshaft has to pass into the 2nd gear sliding piece and gear when these have been lowered into place in the rear compartment. The six plungers for the T and 3rd synchromesh are placed in line as for the 2nd speed on the Phantom III. This saves cost and we cannot see any evidence that one row is inferior to two rows. The gear ratios are 3rd .744, 2nd .503, 1st .322 and R .322, which give overall ratios with a 4.625 axle of 7.2, 9.2 and 14.3 to 1. Figures for the 20/25 and 25/30 are 4.55, 6.25, 9.56 and 15.1 to 1. The synchromesh cones are smaller than those of the 20/25 in the ratio .93, but with the proposed 9o cone angle, this is compensated for and accordingly we shew a cam angle for the T and 3rd of 45o as for the 20/25, and for the 2nd of 50o. * and the front end of the 2nd motion shaft. These are the same as on the rear end of the 3rd motion shaft. It is not thought worth while to adopt the multiple splines in this case as an extra broach would be required. E/HDY.{William Hardy} | ||