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).
Piston design with a deep concave head to improve combustion and reduce detonation.
| Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan079 | |
| Date | 1st May 1926 guessed | |
| contd :- -3- Another type of piston was tried of approx. the same ratio ( 5.35 ) in which an endeavour was made to obtain a more compact combustion space. The piston had a deep concave head and it was thought that perhaps better turbulence would result with reduced tendency to detonate. This sketch shews the arrangement. As no very convincing results were obtained we discontinued the tests but intend to make a further comparison of the two types. At present we should say, that if any, there is very little difference between them. [Diagram] PISTON WITH CONCAVE HEAD SPARK PLUG PISTON HEAD 902 With the present engine we know of no means of eliminating detonation - except by fuel - as we have previously explored the possibilities on the Phantom engine. The only reasonable chance seems to lie in following a similar scheme to the proposed new type Phantom non-detonating head and information as to the practicability of system will be available after tests. While on the question of increasing power it is reasonable to anticipate that a more vigorous engine will tend to make more manifest such troubles as the sensation of 'roughness' and torque reactions, which problems in all probability would best be tackled outside the engine. contd :- | ||