GB790243A - Improvements in aircraft - Google Patents

Abstract

790,243. Aircraft undercarriages. SAUNDERS-ROE, Ltd. Aug. 31, 1956 [June 2, 1955], No. 15837/55. Class 4. An aircraft has wheeled landing gear and at least one hydroski which is movable under the control of the pilot from a position in which the wheels are exposed to first and second projected positions in which the hydroski is operative and has a high angle of attack in the first projected position and a low angle of attack in the second. Fig. 2 shows an undercarriage leg 16 at the foot of which is mounted a landing wheel 11. A hydroski 10 is pivoted at 17 to a lever 13 journalled on the leg 16 at 15. The ski is also pivoted at 22 to a rigid or oleo-link 19 pivoted at 18 to a link 23 pivoted at 24 to link 13, and also pivoted at 18 to a link 14 pivoted at 20 to a forwardly extending lug 21 on the leg 16. A jack 25 extends between a pivot 30 on leg 16 and an arm 26 formed on lever 13. The ski is mounted by the side of the wheel and is cut away at 12. When the jack is fully extended, the ski is raised so that the wheel becomes operative. With the jack in the intermediate position shown, the ski is operative at a high angle of attack. With the jack fully retracted, the angle of attack of the ski is lowered. The jack is shown in Fig. 4 and comprises a cylinder 27 containing a piston 28 attached to rod 29 (see also Fig. 2). The piston is moved by connecting ports 32 and 33 selectively to pressure and exhaust supply lines. When the rod 29 is retracted, the piston 28 is located between the ends of a conduit 34 containing a bleed valve 35, so that when the ski is in the low angle of attack projected position, a damped trimming motion is available. In the high angle of attack position, the piston 28 blocks one end 36 of conduit 34, so that the ski is held rigidly in position. In either of the projected positions, if the ski strikes an obstacle, the piston 28 may move downwardly by moving a piston 37 against a strong spring 38 through fluid trapped between the pistons. In a modification, the link 19 is pivoted to the leg 16 instead of link 14, which is omitted, and the link 19 is extensible with the jack 25 to produce the required ski attitudes.