British Patent Abridgments

A turbojet propulsion unit is mounted in an aircraft so as to be tiltablc to produce vertical thrust, part only of the intake diffuscr, designed for subsonic conditions, being tiltablc with the unit, and the forward part of the diffuscr, designed for supersonic conditions, being fixedly mounted to the airframe. The illustration shows a unit buried in a wing having fixed frame parts 17, I71, and 21. Frame parts 16 161, are tiltablc with the unit about an axis 25. A flap 23 is pivoted at the wing trailing edge. The axes 27, 28, and 29 of the turbine assembly, afterburner, and nozzle respectively, incline progressively downwardly in rearward succession, so that in the normal position (full lines) some vertical thrust is produced (more than half the lift with a high angle of incidence), and the angle through which the unit must be swung to produce a large vertical force is reduced. In the tilted position (chain lines), the part 15 of the diffuscr fixed to the unit is suitable for low speed operation, e.g. during landing or take off. A gap 24 is formed by flap 23, through which air is sucked by the ejector eficct of the nozzle exhaust, to remove the boundary layer from the wing and provide a cooling air flow between the flap and the exhaust gases. In the normal position, gaps 22 arc formed between parts 16 and 21, through which an airflow is similarly induced for removal of the boundary layer and cooling of parts 21. The other illustration shows the installation of two pairs of units in wing parts extending between a central and two side fuselages. The components 17, 18, 19, of the supersonic intake extend laterally to serve a pair of units and arc swept back.