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Calculating the loads and pressures related to a Bentley piston failure.


Identifier  ExFiles\Box 86\2\  scan0116
Date  27th October 1933
  
X236

To E. {Mr Elliott - Chief Engineer} from Hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer}

Hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer} 2/KT.27.10.33.

PISTON FAILURE BENTLEY.

Referring to our conversation, taking

(a) Piston weight 1 lb.,
(b) Piston weight above gudgeon pin .8 lbs.,
(c) Maximum inertia at 4500 R.P.M.
(d) Maximum explosion at 2000 R.P.M.
(e) I.M.E.P. 1.2 M.M.E.P. at 2000 R.P.M.,
(f) Maximum explosion pr. {Percy H. Rose} 6.6-1 c/r 550,

we get -

(1) Maximum inertia load tending to break the gudgeon pin boss in tension = Piston top weight x accn. at 4500 = 1300 lbs. approx.

(2) Maximum explosion pressure tending to break gudgeon pin boss in compression = I.M.E.P. at 2000 R.P.M. x Piston area - total weight of piston x accn. at 2000 = 4400 lbs. - 400 = 4000 lbs. approx.

Maximum compression load about three times maximum inertia load.

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


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