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).
Gearbox and clutch design options, including freewheeling, servo drives, and various braking systems.
| Identifier | WestWitteringFiles\U\2January1930-September1930\ Scan028 | |
| Date | 10th February 1930 guessed | |
| (2) (d) Then comes the reverse unit which is positive by jaw clutches, preferably of epicyclic type. (e) Servo drive (always connected with the car.) I think the gears as shewn in sketch 1. are probably the best type and arrangement we know. But exactly how to control and manipulate them is still doubtful: the following are perhaps the best in order of merit:- (A) A scheme equivalent to synchro-mesh. (B) The Salerni coupling idea on clutch only, or clutch and pawls. (C) Brakes only on 3rd. and perhaps 2nd. speed, like Lanchester, Ford, Wilson, etc, and 1st. by freewheel. (D) Or a combination of these as each gear suggests. I do not think a car is satisfactory running on top gear free-wheeling. I think on this gear at least the car and engine should be coupled together, but now the brakes are so good we might pass free-wheeling on other gears than the top - (this can easily be tested by our freewheel sideshaft.) One would perhaps favour a brake for holding the ring of the 3rd. gear, because it would only need to hold half engine torque, but we may come to the conclusion that brakes sprayed with lubricating oil cannot be satisfactory even for half engine torque. We know the Lanchester's were not, but we have not heard if Wilson's are in Armstrong Siddeley. Progress in the art, and new materials available, may alter the situation. ODD NOTES. When we use the engine vacuum to work the change gear we can make this act only when the clutch is out. This would avoid jerking the car forward or backwards, (patent provisionally the idea of this interlock.) When we use the reverse unit after the direct and indirect clutches we can fit these latter, one or both, with Salerni rings - (already patented I believe.) Since we do not wish to start the car on the 3rd. speed brake this can have self servo action (not patentable.) | ||