THIS paper gives a brief resumé of the development of the Rolls-Royce Kestrel engine and then analyzes the requirements of the high-performance engine of the future, developing at least 1500 b.hp. and operating on fuels of high knock ratings.
The problems investigated include those of engine form, fuels, detonation, waste-heat disposal, cooling drag, cooling medium, and the mechanical and operational features.
Conclusions deduced from the arguments are:
Compression ratios, charge density, and rotational speeds will need to increase and, therefore, cylinder bores and strokes will decrease; it may be necessary to adopt the sleeve-valve type.
The arrangement of the engine will tend to multithrow crankshafts with more than two pistons per crankpin.
It will be necessary to abandon methods of cylinder construction that rely on the art of the pattern-maker and founder, in order that cooling passages may be better controlled in cross-sectional area and more uniform metal sections are secured to reduce heat stresses and weight.
The necessity for having complete knowledge of the fuel's performance in the actual aero engine requires a more exact method of assessing knock ratings.
It will be necessary to liquid-cool the engine in order to deal with the increased waste heat, and to operate the cooling medium at high temperature in order to keep the cooling drag within reasonable limits.