GB792680A - Improvements in aircraft undercarriages - Google Patents

Abstract

792,680. Aircraft skis. ALL AMERICAN ENGINEERING CO. Aug. 4, 1955, No. 22446/55. Class 4. An aircraft landing gear comprises a strut depending from the fuselage, a hydroplaning surface pivoted to the strut, a pilot operated fluid actuated trim cylinder connected to the member for selecting and up- or down-trim position and an over-riding control for selecting free trim. In Fig. 2, a land wheel C and a water ski 12 slotted to receive the wheel are mounted on a shock absorbing strut 16, 17, the latter bearing a projection 18. A hydraulic piston 19 and cylinder 20 extends between the projection 18 and the strut 12. Fig. 5 shows the hydraulic control system for an undercarriage having two struts and skis. A control valve 23 has one port connected by a conduit 21 to the upper parts of cylinders 20, and a second port is connected by conduit 22 to the lower parts of cylinders 20. A third port leads by conduits 24, 30 to a fluid reservoir R, and a fourth port is connected to one port of a valve 29. A second port of the latter is also connected to conduit 30, and a third port is blanked off at 29a. The fourth port is connected to a pressure conduit 33 fitted with a gauge 35 and an accumulator 34 and fed from the reservoir by a hand pump 32. With the valve 29 in the position shown in full lines, the cylinders will be moved relative to the pistons to one extreme position or the other, depending on the position of valve 23, and the skis assume a corresponding up- or down-trim attitude. With valve 29 in the position shown dotted, the cylinders are free to move relative to the pistons, subject to viscous damping, irrespective of the position of valve 23, and the skis can oscillate subject to a damping effect.