A gas turbine powerplant for a V/STOL aircraft in which a vectorable
exhaust nozzle at a forward part (eg. nose) of the aircraft selectably
receives a supply of cold fan air through a duct leading from the fan
through a passageway (28) coaxial with the engine axis and located within
the hub of the fan (12), with the aid of controllable flaps and diverters
(26, 30).