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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).
Progress report on engine development, comparing different designs ('Japan' and 'China') and discussing ongoing experiments.

Identifier  ExFiles\Box 13\3\  03-page325
Date  1st July 1931
  
-3-

does not give us more power and we believe possibly less, due to the cramped arrangement of the valves, but we are proving this out. It is heavier due to its greater height and also awkward for push rod expansion if made in alum.

We know we have shewn you slightly greater power in certain curves V.743 but on analysing are inclined to attribute this to :-

(1) Low speed M.E.P.

Better distribution of weir type pipe and 6 port inlet.

(2) High Speed Power.

All Japans are slightly higher C/R than Chinas i.e. 5.35 instead of 5.25. China has restriction through the block.

Apart from these results it would be difficult to see how the turbulent head itself could give better H.P.

All that we have said in this note we are in the process of confirming, but thought you might be interested to know what we are doing.

We have confirmatory experiments on the go with carburetter arrangements on the 25 HP., and also tests to silence the R.R. twin with the minimum loss of power.

Our other engine work is to try and make any possible improvement to the existing China, of which, no matter of Japan III designs are completed in a week, we shall undoubtedly have to make a further 4 or 5 hundred and sell them.

Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}
  
  


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