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).
The features of slipping clutches, constant mesh gearboxes, and differentials.
| Identifier | WestWitteringFiles\R\2October1927-November-1927\ 89 | |
| Date | 10th October 1927 guessed | |
| - 4 - acquired the velocity corresponding to the lowest engine speed and lowest gear ratio. The heat generated when slipping is taken away directly by the lubricating oil, which is fed to the actual surfaces where the heat is generated and this does not apply to any other known form of slipping clutch. (2) Automatic "free wheeling" allows the vehicle to overrun the engine thus saving fuel on downgrades etc. (3) The moment of inertia of the clutch shaft can be kept very low, thus avoiding the necessity of a clutch stop and allowing easy and quick gear changes. (c) In a constant mesh gear box. Single positively controlled clutches are fitted for each gear. (1) The diameters of the clutches are of the same order as the gear wheels themselves, thus keeping general dimensions and weight low. (2) Engagement of any gear is smooth and positive and can be made at any speed. (3) Very small axial movements are required for engagement or disengagement and these movements can be positively controlled from a single operating shaft. (4) The various advantages of free wheeling described under (a) above. (d) In place of the differential. Spring controlled double clutches at either end of a central driven section of the back axle, so as to allow either road wheel to overrun the engine. (1) Control can be arranged to allow of reversal of both clutches and enable the car to be reversed or allow of engine braking down hill. | ||