| 摘要 |
A jet engine having at least one combustion chamber with a propelling nozzle connected behind it, achieves in a constructionally simple manner and with a high propulsion effect a cross-sectional configuration of a hot gas flow duct bounded by the propelling nozzle that is highly variable with respect to the nozzle throat area as well as to the outlet area. The propelling nozzle contains a divergent lengthening part which is axially movable for the outlet-side expansion of the hot-gas flow duct. In the moved-out position, the lengthening part connects essentially in the corresponding shape to the divergent outlet end of the nozzle outer wall fixed to the engine and, in the moved-in condition, forms together with it an air outlet duct which encloses the fixed nozzle wall end in a ring-shaped manner and whose cross-section can be regulated. In the lower flying speed range, where the propelling nozzle lengthening is not required for the expansion of the outer contour of the hot gas flow duct, a secondary air injection takes place that is uniform along the whole outer circumference of the fixed nozzle end, and in addition, in the interior of the propelling nozzle, for the interior bounding of the hot gas flow duct, a mushroom-shaped central body is arranged which, with its largest cross-section can be axially adjusted between the plane of the smallest cross-sectional surface of the fixed nozzle outer wall and the outlet plane of the moved-out nozzle lengthening.
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