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).
Oil consumption issues in Kestrel engines related to cylinder liner construction and distortion.
| Identifier | ExFiles\Box 179\2\ img095 | |
| Date | 30th December 1931 | |
| ORIGINAL To-R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Yng. cc to Mr. Ever. c. to Mr. H.{Arthur M. Hanbury - Head Complaints} c. to Mr. Hs{Lord Ernest Hives - Chair}/Yng.7/KT.30.12.31. X3866 X2965 CYLINDER LINER CONSTRUCTION & OIL CONSUMPTION - KESTREL ENGINES - We have considered for some time that our oil consumption troubles have been due largely to distortion of the cylinder liners. Fig (i) attached, shews the construction of the standard liner. Fig (ii) attached, shews the construction of the liners in the detachable head cylinder blocks; with this arrangement the liners are not in compression when the blocks are tightened down. Tests have been carried out using the short skirt pistons N.37271 (suitable for articulated rod engines) having the scraper ring above the gudgeon pin. The following comparisons of oil consumption may be drawn. (i) Detachable head cylinders fitted to Kestrel No.25 engine gave 3.19 pints/hour average over two 2 hour tests. (ii) Standard cylinder blocks and liners on the same engine increased the consumption to 8 pints/hour. - Oil pressures on the above tests were, Main 68 lbs/sq.in. Auxiliary 7.5 lbs/sq.in. (iii) Pistons of exactly the same form, profile and scraping arrangements - N.37281 - gave 12 pints/hour when fitted in Kestrel engine No.607. This engine was fitted with a long bearing crankshaft, short cylinder liners (for articulated rods) and ran with oil pressures of - Main 103 lbs/sq.in. Auxiliary 7 lbs/sq.in. From the foregoing results we may conclude that the distortion of our standard liner has raised the oil consumption of a piston by approx. 150%. It is reasonable to suppose that the 50% increase of (iii) over (ii) is due to the shorter liners and the greater oil pressure. We suggest that a set of really stiff liners are made up for an engine, and tried out for oil consumption. If the consumption is good the question of lightening the liners consistent with retaining the stiffness, can then be investigated. Hs{Lord Ernest Hives - Chair}/H.R.Young. | ||