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).
Piston ring performance, comparing pegged vs. floating rings and different piston materials.
| Identifier | ExFiles\Box 132\5\ scan0063 | |
| Date | 11th March 1939 | |
| -11- Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation}3/MH.{M. Huckerby}11.3.39. It is undoubtedly true that pegging prevents the rings from turning round, and so gives them a better chance to bed in to the bore. Also, they are able to remain "bedded in". In the case of floating rings, not only have they to bed in to the bore, but as they turn (as they undoubtedly do) the only way in which the perfect seal can be attained, is to gradually wear the bore to a perfect circle. To those who feel so strongly for pegged rings it can be argued that they must be very confident of the fact that their bores are not round. There are numerous types of ring available on the market to-day, but the one in which we are most interested is a tin plated ring, which has a pressure which just prevents flutter. At the same time, a point which remains to be cleared up, is to find out how much high pressure rings influence correct oil control, when the right amount of oil is thrown up the bores. CONCLUSIONS. A programme has been sent to HFS. allocating the various experimental materials to the Company's development cars. This includes:- (1) The short insert. (2) Standard block in improved material. (3) Comparison of the latest R.R. and Aerolite piston. At the same time, tests are being done on the road to compare the two types of Aerolite piston (skirt clearance) for oil consumption, and to obtain a value for the tin plated ring. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} | ||