Rocket motor extendible nozzle exit cone

A rocket motor extendible nozzle for attachment to a rocket motor nozzle having a longitudinal axis and a throat area for increasing the ratio of the effective rocket motor nozzle/extendible nozzle exit cone effective area to the rocket motor nozzle throat area comprising:

• an arcuate-shaped membrane of ductile heat resistant material, said membrane having opposed arcuate sides one of which is longer than the other and having ends that are adapted to be brought into edge-to-edge relationship to form a frustum of a cone having an aft end and a longitudinal axis in alignment with the longitudinal axis of the rocket motor nozzle, said membrane having a portion forming the aft end of said frustum of a cone, said membrane portion being deformed by a plurality of cooperating crease lines of first and second sets, each of the crease lines of said first and second sets having an apex, with the apex of each of the crease lines of the first set pointing at a viewer from the exterior of the membrane as formed into a frustum of a cone and the apex of each of the crease lies of the second set pointing away from the viewer, the crease lines of said first set running both transversely and longitudinally of said frustum of a cone with respect to the longitudinal axis thereof and the crease lines of the second set running longitudinally only thereof whereby said frustum of a cone may be folded inwardly, axi-symmetrically thereof, in multiple layers from the aft end thereof for compact stowage relative to said rocket motor, and whereby said extendible nozzle may be unfolded to the extended position thereof by a forward-to-aft flow of rocket motor gas therethrough upon firing of said rocket motor.