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).
Report page on engine knock testing, including a diagram of a cylinder and analysis of stiffening cylinder skirts.
| Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan006 | |
| Date | 1st October 1925 | |
| contd :- -6- Results proved encouraging. When using a sounding rod at the cylinder base 'knocks' were more severe than with the previous block tested but apart from this, opera-tion was silent when listen-ing 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 cylinder bore, at that particular part, by .0022". When kxx 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/LGS.10.25 - we suggested a reason for the contd :- [Text from diagram]: Diagram 2 CYLINDER END OF CYLINDER .175 .240 2.000 | ||