Low drag variable plug jet exhaust nozzle

Claim 1

AN AXISYMMETRIC EXHAUST NOZZLE FOR JET PROPELLED AIRCRAFT ADAPTED TO FLY AT SUBSONIC OR SUPERSONIC SPEEDS COMPRISING: A FIXED ANNULAR SHROUD MEMBER INCLUDING A CYLINDRICAL OUTER PORTION AND AN INNER PORTION, BOTH OF SAID PORTIONS TERMINATING DOWNSTREAM IN THE SAME PLANE WITH RESPECT TO THE NOZZLE AXIS, SAID OUTER PORTION HAVING A SHALLOW ANGLE WITH RESPECT TO THE NOZZLE CENTERLINE IN ORDER TO REDUCE EXTERNAL DRAG AND SAID INNER PORTION CURVING INWARDLY TO TURN THE EXHAUST JET TOWARD THE NOZZLE AXIS; AN INNER MEMBER COAXIALLY ARRANGED WITH RESPECT TO SAID SHROUD MEMBER AND FORMING AN ANNULAR NOZZLE THROAT AREA WITH SAID INNER PORTIOM, SAID INNER MEMBER HAVING SETS OF PIVOTABLE FLAPS WHICH COOPERATE TO VARY THE NOZZLE THROAT AREA IN ACCORDANCE WITH VARYING AIRCRAFT OPERATING REQUIREMENTS, SAID THROAT AREA BEING LOCATED AXIALLY WITH RESPECT TO THE NOZZLE IN SAID TERMINATING PLANE DURING ALL VARIATIONS OF THROAT AREA; AND MEANS FOR COOLING SAID NOZZLE INCLUDING WALLS FORMING PASSAGES FOR DIRECTING A FILM OF COOLING FLUID ALONG THE OUTER SURFACE OF THE PIVOTABLE FLAPS OF SAID SETS.