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).
New spring ring device and other modifications for piston pins on various engines.
| Identifier | ExFiles\Box 66\1\ scan0099 | |
| Date | 1st August 1926 | |
| To RG.{Mr Rowledge} Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to BJ. Wor.{Arthur Wormald - General Works Manager} BY.{R.W. Bailey - Chief Engineer} X8040 R2/M28. 8. 26. RE: PISTON PINS. X. 8040 X. 2603 CONDOR, FALCON 10., PHANTOM AND GOSHAWK. X. 5040 X. 3996 We believe that all the pistons should be fitted with the spring ring device because it is the one which promises to give greater reliability being at the same time light and inexpensive, and less liable to suffer from incorrect workmanship. The small item we have added of a screw to keep the split one way round halves the risk of movement in the ring through high speed reciprocation in the piston. We believe the dimensions we have given are the best for the purpose. We have given two for a test to make a choice. When this choice is made the same proportion should be used for the various sizes. It is assumed that really good quality tempered pianoforte wire will be wound upon a mandrill equal in size to which the ring is compressed when feeding it into the hole. Such a wire when released will spring out to the max. that its temper will give. This max. size will be such as to give the max. pressure of the ring within its groove that the wire is capable of. It will be noticed that all the pistons will have to be slightly lengthened in the bore to accommodate the groove and the wire, but all the piston pins will be capable of being lightened at each end and lapped to a beautiful finish, which should add to their reliability. It is assumed the little end will be fitted with loose bushes, and the con. rods will be tested to see if we can delete the oil pipe. This should be done with great caution. R.{Sir Henry Royce} | ||