Page 19 - The Jet Engine

Basic mechanics

sustained high Mach number cruise conditions combustion chamber for cooling purposes before the
where the engine operates in the ram jet mode. gas enters the turbine. This fuel-rich mixture (gas) is
then diluted with air from the compressor and the
20. The turbo-rocket engine (fig. 1-12) could be surplus fuel burnt in a conventional afterburning
considered as an alternative engine to the turbo/ram
jet; however, it has one major difference in that it system.
carries its own oxygen to provide combustion, 22. Although the engine is smaller and lighter than

21. The engine has a low pressure compressor the turbo/ram jet, it has a higher fuel consumption.
driven by a multi-stage turbine; the power to drive the This tends to make it more suitable for an interceptor
turbine is derived from combustion of kerosine and or space-launcher type of aircraft that requires high
liquid oxygen in a rocket-type combustion chamber. speed, high altitude performance and normally has a
Since the gas temperature will be in the order of flight plan that is entirely accelerative and of short
3,500 deg. C, additional fuel is sprayed into the duration.

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