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).
Raising questions and discussing test results regarding the radial thickness and pressure of engine rings, comparing them to American standards.
| Identifier | ExFiles\Box 148\3\ scan0160 | |
| Date | 13th October 1936 | |
| -2- Now to the points we should like to raise - Radial Thickness. What do you consider should be the radial thickness of rings for this type of engine ? We know that generally in America you use a much greater radial thickness than we use here. What are the reasons for this ? Radial Pressure. What would you consider as an ideal radial pressure to use ? This of course is intended for a base from which to make rings of something like correct proportions. We have not done as yet any work with high tip loading. Do you use any proportions for this, say tip load measured on your roller gauge in proportion to the average of the loads on the pins, or do you use the method of making the rings so much "longer" over the tips in, say, so many 1/1000 per inch diameter ? We have used high pressure rings but have so far not met with much success. We have found that we can get down to the same consumption with our standard rings in about the same time. The pressures we used for the high pressure rings were - 2nd Compression Ring 43 lbs/sq.in. 1st " " 28 " " " Scraper Ring 47 " " " We rather think these pressures may have been too high, because we have had signs of metal-to-metal contact. These rings had the American proportion for radial thickness, namely D/23.2 . We also noticed that with these rings as the engine load was reduced, the oil consumption went worse, and that after running for some time at 1/4 load at 4,000 R.P.M., we could not get back to the original figure for full load until we had given the rings some further running in. With our standard rings there is no difference in consumption when running at either full or half load. | ||