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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).
Stress levels of a 25 HP valve spring and the trial of a new set.

Identifier  ExFiles\Box 181\M13\M13.2\  img138
Date  28th November 1931
  
ORIGINAL

To E.{Mr Elliott - Chief Engineer} From Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}
c.c. to By.{R.W. Bailey - Chief Engineer}

Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}4/MJ.28.11.31.

25 HP. VALVE SPRING.

X5060.

We are sending you details of the valve spring position particularly as regards the car now doing 10,000 miles in France.

The D.O. consider these springs too highly stressed but we do not agree with the standard method of calculation and as you will see, have run springs at a higher stress. Further the small coil clearance appears to us to be an advantage as the surging of the spring rendering the coils choc-a-bloc does not materially increase the stress.

We are, however, going to try a set of springs to the accompanying sketch in order to have your recommended stress range.

Hs{Lord Ernest Hives - Chair}/H.Grylls.

Attached Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}1/MJ.28.11.31.
BY/SS.{S. Smith}4/N24.11.31.
Sketch Hs.{Lord Ernest Hives - Chair}477.
  
  


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