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).
Use and effectiveness of 'The Perfect Circle' piston rings on aero and Phantom engines.
| Identifier | ExFiles\Box 16\1\ Scan197 | |
| Date | 22th October 1927 | |
| X741 To Ps. from Hs.{Lord Ernest Hives - Chair} Hs{Lord Ernest Hives - Chair}2/LG22, 10.27. RE. PISTON RINGS & OVEROILING. X2103 [crossed out] X741 With reference to your Ps1/IL20.10.27. We are actually using on our aero engine pistons a scraper ring identical to the sample you have sent us. We have been doing this for some months. The originators of the ring are "The Perfect Circle' ring people - made in U.S.A. We are also trying out these rings on a Phantom engine. If you could obtain this type of ring and try them in a Phantom engine piston, we should be very pleased to hear the results. Our results so far however shew that this type of ring is not as effective as the 'L' shaped ring, but it does of course have the advantage that it remains a constant efficiency. Hs.{Lord Ernest Hives - Chair} | ||