Gas turbine engine including a variable area nozzle

Abstract

Known variable nozzle actuating mechanisms are of complicated construction. This is acceptable where the devices are used on engines which power manually controlled aircraft. The invention although usable on engines used as described above, is particularly useful on engines which power pilotless vehicles i.e. missiles by virtue of its simplicity and therefore reliability. The variable nozzle has flaps which are held in a first throat constricting position by a knuckle mechanism. Opening of the throat is achieved by moving ram rods to the left as viewed in the drawings, to straighten the knuckle mechanism about an intermediate pivot. Gas loads on the inner surfaces of the flaps push the flaps outwards. At all operating positions of the flaps except this fully open position, gas loads are transferred via the knuckle mechanisms onto the fixed cowl. Secondary flaps may be included.