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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).
Calculations on crank radius to rod length ratio and its effect on engine forces and flywheel inertia.

Identifier  ExFiles\Box 103\2\  scan0176
Date  29th January 1931 guessed
  
(2)

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

I read Mr. Elliott's memo. - r/l :- r = crank radius, l = rod length. If this is correct my calculation shews 33% difference between ratio 2 = 100% ratio 1.75 = 150%, 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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