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).
Technical discussion on gearbox design, comparing cone placement on the upper shaft versus the layshaft, and the implications for synchromesh gears.
| Identifier | ExFiles\Box 136\4\ scan0112 | |
| Date | 24th October 1934 guessed | |
| - sheet 6 - (1) When the cones are placed on the upper shaft as on the Alvis and Hillman, the operation of the gear change requires too much effort except perhaps on a small car. (2) When the cones are on the layshaft we get easy operation but the pitch speeds of the 2nd and 1st speed gears are high when in top gear and there will be extra noise and power loss due to oil drag. We have the second speed working under these conditions, as far as I am aware with no perceptible disadvantage, and it may be that the addition of the 1st speed, with 16% higher pitch speed than for the second speed, would also make no perceptible difference. If this proved to be so I see no reason why we should not include the first speed as the operation would be as good as for the 2nd speed and there would be no increase of the length, weight or cost of the box. Whether there is noticeable noise from the 1st speed gears when of the synchromesh type would need proof by extensive testing, as it is a thing that is liable to vary with different boxes of the same type and the advantage of synchronising the 1st speed would be too dearly bought at the price of an increase of noise in top gear, in my opinion. HDY.{William Hardy} | ||