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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).
Cause and potential solutions for over-run vibration in an E.A.C. engine.

Identifier  WestWitteringFiles\L\Jan1924-March1924\  Scan96
Date  9th February 1924
  
TO HS.{Lord Ernest Hives - Chair} RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design}) FROM R.{Sir Henry Royce} S E C R E T.

E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C. ENGINE.

OVER-RUN VIBRATION. V9550 / X634

The source of this trouble I believe must be the variation of the kinetic energy in the pistons and little ends. This varies the speed of the flywheel. Behind this is a revolving mass comprising servo drum, gearbox wheels, couplings torsionally hanging on the l.l shaft which is of a suitable rigidity to make a period at the 40.MPH. Several things are possible to make it less or alter its speed:-

(1) Lighten the pistons, etc. Result less noise same speed.

(2) Increase the flywheel. ditto

(3) Decrease the inertia of the mass behind the flywheel. Result less noise & higher speed.

(4) Increase the rigidity of the shaft mentioned. ditto

(5) Fit friction damping ring or disc near centre of torsionally oscillating mass. Probable cure.

R.{Sir Henry Royce}
  
  


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