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).
Performance of 'perfect circle' versus 'L' shaped piston rings and the number of rings per piston.
| Identifier | ExFiles\Box 16\1\ Scan208 | |
| Date | 1st August 1928 | |
| Hs.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} from R.{Sir Henry Royce} c. to BJ. RG.{Mr Rowledge} Fl. X741 R6/1120.8.28. PISTON RINGS. X.741 X.5040 I am very pleased to hear that the perfect circle piston ring with slight modifications promises to fill the duty of a scraper ring satisfactorily. This is the type I have most faith in for permanency. We are, or soon shall be, in a position to abandon out 'L' shaped rings because of their want of life, and their unsatisfactory wearing and production features. Will BY.{R.W. Bailey - Chief Engineer} and Hs.{Lord Ernest Hives - Chair} try to stop the production of all the 'L' shaped rings, especially those which do not give a satisfactory bearing area in the grooves of the piston. I understand there is much of this work of re-fitting going on at Cricklewood and other outlying stations. If this unsatisfactory work could be promptly stopped it would relieve my anxiety that we are doing unsatisfactory work. Regarding the number of rings I do not think it is necessary to have 5 rings, 4 pinned rings being thought to be as reliable as 3 pinned and 2 unpinned. The pistons with 4 rings on 12.G4. were very satisfactory generally, but it is thought that one made a noise like leakage, and it is certain that the one compression was poor. This should not condemn a 4 ring piston, and it will be remembered that the defect only occurred in one piston, and at very light explosions, which would suggest that this particular piston or cyl. bore was defective in fitting rather than in design. R.{Sir Henry Royce} | ||