F02K 1/1292

Varying effective area of jet pipe or nozzle by means of pivoted flaps {of three series of flaps, the upstream series having its flaps hinged at their upstream ends on a fixed structure, the internal downstream series having its flaps hinged at their upstream ends on the downstream ends of the flaps of the upstream series and at their downstream ends on the downstream ends of the flaps of the external downstream series hinged at their upstream ends on a substantially axially movable structure}