Jet vectoring apparatus

A propulsive gas generator for use in an air vehicle comprising a front end for receiving air, a back end for expelling air to form a propulsive jet flow, and a longitudinal axis between the front end and back end, a nozzle at the back end, said nozzle comprising an internal throat aperture and an exit aperture at the back end, wherein the throat aperture and the exit aperture each comprising an aperture size wherein the propulsive gas generator is configurable to provide a co-operating post exit surface extending to a rear of the exit aperture, wherein the post exit surface comprises a length and a width, and a forward end oriented towards the front end of the gas generator and a distal end furthest from the front end of the gas generator, wherein at least one of the throat aperture, exit aperture, and post exit surface length are configured to be variable, the propulsive gas generator further comprising control means for controlling the size of the at least one of the throat aperture, exit aperture or post exit surface length, wherein the control means is configured to receive an input signal, and in response to the input signal vary the size of at the at least one of the throat aperture, exit aperture and post exit surface length to create a pressure differential on the post exit surface thereby angling the propulsive jet flow relative to the longitudinal axis.