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).
Outlining design points and recommendations for pistons in aero engines.
| Identifier | ExFiles\Box 66\1\ scan0126 | |
| Date | 22th January 1927 | |
| To E.{Mr Elliott - Chief Engineer} 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} F.10. PISTONS AND OTHER AERO ENGINES. X.3996 X.8040 X.4004 I should not be too keen to send out engines with very high compression. Tests should be higher than engines for long flight. The following points should be adopted unless you know to the contrary. (1) Slightly lower than tested compression ratio. (2) Slightly more metal in piston pin to increase its stiffness and strength. .1 lbs. might be well spent. (3) Stiffer rings giving more wall pressure might influence gumming up. (4) Pistons touching cyl. wall where-ever possible to conduct heat away. (5) All rings gas holding, no perforation, bottom scraper only, and no metal below. (6) Top ring slightly lower down, possibly keeping cooler, and having trapped oil above .3" or .4" seems to be correct. (7) Bosses well supported against high explosive pressures that are natural for over 140 M.E.P. (8) Y. metal is considered best but some of the cast pistons should be tried if it is thought that the better shape compensates for the less good quality metal. Possibly there are more points, but let us get as many good ones as possible, adopted. R.{Sir Henry Royce} | ||