Abstract: A reception coupling for air-to-air refuelling has a main body and a fuel passage. A moveable valve member is provided for opening and closing the fuel passage. A chamber is separate from the fuel passage. A portion of the valve member can be accommodated in the chamber as the valve member moves toward an open position, shielding that portion from effects of pressure in the fuel passage.

Abstract: A drogue assembly (10) for in flight refueling includes a circumferenal array of triangular support arms which carry a drogue parachute (29) which extends circumferentially around their shorter sides. Each support arm is pivoted and mounted on a pivot pin (19) at its apex for pivotal movement in a radial direction. At least alternate ones of the support arms carry leaf springs which extend into pockets (51) formed in the drogue parachute (29). The leaf springs act on the drogue parachute (29) in opposition to air pressure loading on it in flight so that it tends to increase the chord angle of the drogue parachute (29) from the leading edge. Hence the effective area of the drogue parachute in flight is varied automatically above a certain predetermined minimum which depends on the dimensions of the trailing edge so it is reduced as air speed is increased and vice versa.

Abstract: A bimorph piezoelectric flapper element is mounted at one end in a valve casing so that it extends into a valve chamber as a cantilever. The flapper element tapers to the unsupported end on which a fluorosilicone blocking plate is mounted. An outlet port is formed by a tubular boss which projects into the valve chamber and which tapers to a fine annular rim formed around a mouth of a bore at the tip of the boss. The blocking plate is normally held by the flapper element seated on the tip of the tubular boss to close the outlet port, the tip making an indentation in the fluorosilicone whereby to form a `bite` seal. The blocking plate is unseated by the application of a low voltage to the bimorph piezoelectric element. The valve is suitable for hydraulic fluids and may be operated by optical power.