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 calculations and proposed modifications for pedestal pistons.
| Identifier | ExFiles\Box 66\1\ scan0140 | |
| Date | 1st June 1927 | |
| To Hs.{Lord Ernest Hives - Chair} from E.{Mr Elliott - Chief Engineer} c. to BJ. BY.{R.W. Bailey - Chief Engineer} X 8040 E1/M1.6.27. PEDESTAL PISTONS. X.8040 X.3996 X.4004 We do not agree with your calculations giving the stress in the bolts of the pedestal piston. We think the co-efficient of expansion for tempered steel should be taken as .0000126 instead of .000007. Moreover we think more length should be allowed for the bolt stretch. Our figures bring the stress due to difference of expansion roughly in the neighbourhood of 20 tons/sq.in., which is xxx what we originally calculated. Nevertheless we agree that although no trouble has been experienced with the alum. pedestal pistons it would be advantageous to use larger heads for the bolts than the standard cheese-heads. We propose to introduce this modification in the new design of pedestal piston to be made as a forging in 'Y' metal. E.{Mr Elliott - Chief Engineer} | ||