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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 design, focusing on the reverse pinion, gear ratios, and associated components.

Identifier  ExFiles\Box 178\3\  img155
Date  5th May 1932
  
ORIGINAL
DA{Bernard Day - Chassis Design}/HDY.{William Hardy} Er. ) FROM R.{Sir Henry Royce}
HS.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} ) (At Le CanadelHenry Royce's French residence.)
R3/42.5.32.
Sent from WW. 5.5.32.
C. to CO. WOR.{Arthur Wormald - General Works Manager}

GEARBOXES - ALL SIZES -
ALSO PEREGRINE & BENSPORT.

X 7310
X 5310
X4583
(4007)

REVERSE PINION.

It was not anticipated that anyone would feel the reverse pinion in getting into 1st. gear, but you will see by telegram. Our enemies can have something to say, which can be avoided by a little trouble.

The two great wheels are 3/8" widths and clearances apart -

[Diagram 1]
Second.

[Diagram 2]
Second.
1st. & 2nd.

[Diagram 3]
To engage 2nd.
Reverse.

[Diagram Label]
Double width movement on reverse pinion.

The double movement of the reverse pinion should be obtained by some simple levers in the box, and not by extra movement of the change speed lever, which I think would be awkward and troublesome, and may involve us in lots of difficulties in the car and in the tower.

The lever and tower should be very simple, and of crude and robust pieces - see other boxes. I do not think we want an interlock of sliders, and a gate, but do not remember exactly.

The taper pins, rivets, etc, must be much larger in dia., and shorter to make them practical. Those shown are too small, especially in the synchro mesh cones. Press on and pin, either parallel or taper, is cheapest, and practicably good. (See RHC.{R. H. Coverley - Production Engineer} who is a good authority on this sort of work.)

Gear ratios will do like on a sports car, or a compromise. It is an academic argument to need two ratios. Make the best average, and if we must have two, let it be proved by trial. I like gears near together as on a sports car, or nearly so.

R.{Sir Henry Royce}
  
  


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