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 for stress in the bolts of a pedestal piston and proposing design modifications.
| Identifier | WestWitteringFiles\Q\April1927-June1927\ 106 | |
| Date | 1st June 1927 | |
| TO HS.{Lord Ernest Hives - Chair} FROM E.{Mr Elliott - Chief Engineer} C to B.J. BY RECEIVED JUN ORIGINAL E1/M1.6.27. X8040 X.3996 X4004 PEDESTAL PISTONS. 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 per sq. in., which is what we originally calculated. Nevertheless we agree that although no trouble has been experienced with the aluminium 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} [Signature] | ||