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).
Engine testing, focusing on cylinder skirt deflection and piston knocks.
| Identifier | ExFiles\Box 66\1\ scan0089 | |
| Date | 5th October 1925 | |
| contd :- -6- Diagm. 2 CYLINDER .175 .240 2.000 were more severe than with the previous block tested but apart from this, operation was silent when listening in the normal way. Consequently this method was accepted as a reasonable cure for the engine tested and attention was turned towards finding the reason why stiffening up the cylinder skirts had proved to be so effective. Indicators were employed to see if deflection took place at the base of the skirt, but none could be read on the instruments which were sensitive enough to detect a movement of .0005". Another test was made in which a steel band encircled the bottom of the cylinder skirt and could be tightened by means of a nut and bolt. When fully tight it was found that it would contract the cyl. bores, at that particular part, by .0022". When listening at the skirt with a sounding rod, the knock was slightly worse with the band tight, or the cylinder contracted .0022". Referring back to a previous report on piston knocks - Hs{Lord Ernest Hives - Chair}/ACL/LG5.10.25 - we suggested a reason for the knock and in the light of our recent experiments it still seems a reasonable explanation. The reason stated was as follows :- contd :- | ||