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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).
Effects of changing the rod length to crank radius ratio on engine forces and flywheel inertia.

Identifier  ExFiles\Box 13\9\  9-page8
Date  19th April 1934 guessed
  
(2)

If my conclusions are not correct perhaps E.{Mr Elliott - Chief Engineer} and H/TSN.
will write to me again on the subject.

I read Mr. Elliott's memo. - r & : - = crank radius,
l = rod length. If this is correct my calculation shews 33%
difference between ratio 2 = 100% ratio 1.75 = 133%, or equal to
reducing the weight of the piston rings and little end by 1/3rd.,
and also forces are 50% greater, needing 50% more inertia in
flywheel for a given speed change due to this cause (i.e. not
power impulses - gas pressures.)

R.{Sir Henry Royce}
  
  


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