The invention provides a
combined cycle engine. The
combined cycle engine comprises a casing, a fixing guide column and a
continuous rotation knock engine as an ejecting device. The casing is provided with an air inlet and a
supersonic nozzle. The fixing guide column is provided with a fuel inlet and an oxidant inlet. The
continuous rotation knock engine comprises a central conical body, a fuel collecting
pipe, a plurality of fuel conveying channels, a fuel inlet
pipe, a plurality of fuel nozzles and a ring-shaped body. The central conical body comprises a front body and a rear body, the casing is fixedly arranged by surrounding the outer surface of the whole rear body and part of the front body, a first
combustion chamber extends axially and is defined by the casing, the outer surface of the whole rear body and part of the front body, the
tail end of the first
combustion chamber, which is in an axial direction, is an outlet, space between the casing and the portion behind the rear body of the central conical body inside the casing forms a second
combustion chamber, the first
combustion chamber is communicated with the second
combustion chamber through the outlet, and the second
combustion chamber is communicated with the air inlet. Therefore, the
combined cycle engine can improve the ejecting efficiency of the ejecting device and simplify the structure of the ejecting device.