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Required alterations to the 40/50 and 25 HP gearboxes, referencing Dr. Maybach's designs.


Identifier  Morton\M19\  img127
Date  2nd March 1931
  
COPY.

TO R. {Sir Henry Royce} From Hs {Lord Ernest Hives - Chair} /Rn. {Mr Robinson} Hs {Lord Ernest Hives - Chair} /Rn. {Mr Robinson} 14/KT.2.3.31.
c. to Da. {Bernard Day - Chassis Design}
c. to By. {R.W. Bailey - Chief Engineer}
X. 7310.
c. to Sg. {Arthur F. Sidgreaves - MD} X. 5310.
X. 523.

R.R. EASY CHANGE SILENT GEARBOXES.
----------------------------------

In view of the information obtained from Dr. Maybach, it appears that we require some alterations to the existing designs at present being made.

(1) 40/50.

The fact that we cannot have a neutral position with the Maybach dogs does not affect the change for the silent epicyclic third on this box, because it is not designed to have a neutral position. The change to obtain the two silent lower gears easily, however, will have to be altered because it is essential that a neutral position shall be available and such a position is unattainable with Maybach dogs. If we turn this set of Maybach dogs into a normal dog change with direct operation from the gear lever, the neutral difficulty will be recovered and we shall have a gearbox that will give us a silent easy change third, and a silent second and first but without an easy change for these lower gears.

(2) 25 HP.

This box being designed so that it relies on the Maybach dogs having a neutral position if the lower gears are to be operateable, it will either be necessary to dispense with the easy change or re-design the box so that the Maybach dogs can be incorporated without a neutral position.

Of course we may find, on the small car, that a straight dog clutch can be made to give a relatively easy change, but experiments we have made on the 40/50 have not so far been very successful.


Hs {Lord Ernest Hives - Chair} /Rn. {Mr Robinson}
  
  
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).


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