Exhaust nozzle assembly with dual unison ring structure

Abstract

A variable area exhaust nozzle has primary, axially movable flaps tied to an inner unison ring having a box-like cross section and axially movable external flaps tied to an outer unison ring of box-like cross section. The inner and outer rings are concentric, radially aligned, and separated by an engine case. The rings are interconnected by a plurality of pins extending radially from within the outer ring box section to within the inner ring box section through axially extending slots in the case between them. The pins are attached to the rings in a manner preventing relative axial movement therebetween and permitting relative radial movement. When one of the rings is actuated in an axial direction, the other moves axially therewith, the axial actuation force being transmitted by the interconnecting pins. The pins also resist the overturning moment on the rings caused by loads on the nozzle flaps.