Month in the Patent Office

In a folding wing aircraft with a tricycle undercarriage in which the folding of the wings causes the centre of gravity of the aircraft to move behind the rear axle of the undercarriage, the aircraft tail is supported when the wings are folded by a strut 15, which is also an arrester hook for engaging wires on a landing deck for stopping the aircraft, retractable manually into a housing 10α near the tail of the aircraft. The arrester hook 15 is pivoted about an axis 16 to the aircraft and is extended and supported by a pneumatic jack 20 whose piston 19 is pivoted at 18 to a lever 17 integral with the hook and whose cylinder is pivoted at 21 to a bracket 21α on the aircraft. The exhaust valve 36 of the jack 20 is automatically closed by a connexion 39, 38 to a lever 37 (see FIG. 4), fast on the shaft 16 when the arrester hook 15 is (manually) retracted, a lost motion device in the connexion preventing the automatic opening of the valve 36 by extension of the strut.