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).
The practice of pinning piston rings, comparing American methods with the company's 40/50 and Hawk engines.
| Identifier | ExFiles\Box 35\3\ scan 030 | |
| Date | 30th December 1922 guessed | |
| contd:- -2- America had abandoned pinning the piston rings. I think this would reduce efficiency of gas-tightness, and occasionally become disastrous unless a more complex ring was used. Personally I am entirely in favour of a large number of narrow simple rings alternately pinned at right angles to the piston pin, the pinning being slightly staggered to break the joint. This is our 40/50 practise, and but I am not sure what pistons are on the Hawk engine (Hawk-Northcliffe, not Goshawk) which is here. They seem extremely good. R.{Sir Henry Royce} | ||