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 comparison and critique of gearbox components and design features for various car models.
| Identifier | ExFiles\Box 136\4\ scan0109 | |
| Date | 1st November 1933 guessed | |
| - sheet 3 - (2a) The reverse is by a double width pinion engaging with the 1st speed pinion and an extra large gear alongside the 1st speed wheel. The reverse pinion has double the normal travel and is stationary when not in use. Roller bearings of the self locating type such as we are proposing for the SpectreCodename for Phantom III are used but they are of the LL. type which has both races solid and a smaller number of rollers than the F.{Mr Friese} type which we propose. (3) The synchromesh clutches are all on the upper shaft and are not as large as they could have been made by the use of our more expensive construction by about 30%. Three locking cams are used as in the original Buick construction and steel balls are used instead of our cylindrical plungers. The ball is cheaper but does not give as much spring length as the plunger. (4) The actuating forks operate directly on the collars without the use of stirrups which we provide because of the fork deflection under load. (5) The selector rods slide in rigid bearings with no accommodation for distortion of the rods by the forks. To make matters worse the top and 3rd speed selecting rod is without any support on one side of the fork. (6) A pump delivers oil to the hollow 3rd motion shaft to lubricate the needle roller bearings of the loose gears. (7) Untrapped spring rings are considerably used to locate gears and bearings but not where there is any great side thrust. (8) The reverse stop is of the lateral spring loaded type. Hillman-Minx. I have not yet secured a trial of this car but hope to be able to do so locally within a few days. Design. As illustrated in the Motor of the 11th September. The Humber 12 has a box of similar design. Hillman Minx Ratios .66, .4, .28. (1) As you remark, no doubt consideration of cost has governed the design to a great extent and accounts for the shortness of the | ||