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).
Conclusions from a cylinder head test regarding hot spots, compression ratios, and ignition plugs.
| Identifier | ExFiles\Box 19\7\ Scan133 | |
| Date | 18th April 1929 guessed | |
| contd :- -3- CONCLUSIONS : (1) It is suggested that there is a definite hot spot immediately under the plug on the actual cyl. XX head tested. (2) It is proposed to modify the combustion chamber to suit the lower compression ratio recommended as on LeC.2689. (3) It is proposed to withdraw the plug slightly as on LeC.2689. (4) Consider cooler ignition plugs for sue with this head. It may yet be found possible to use a higher compression ratio than 5.1 on the 20, say 5.25 and with this in view a slight modification could be introduced into pattern instructions to leave the floor of the head about .050" thicker as shewn by the dotted line in fig.2, LeC.2689 so that the head could be produced to suit the higher ratio if and when required. E.{Mr Elliott - Chief Engineer} | ||