Month in the Patent Office

Abstract

A flap or aileron capable of being moved rearwardly and tilted relatively to the fixed part of an aircraft wing, so as to form a nozzle gap between the fixed part and the aileron or flap, is supported by a sliding pivot or a system of pivoted links arranged so that the flap or aileron has a motion compounded of a translation and a rotation. An aileron or flap II, Fig. 2, is pivoted about a pivot 1 capable of being moved along a slot 10 by a link 8 and lever 9 until it is in the position IIa. A gap is thereby opened between the plane and the aileron or flap, but it is ineffective until the aileron or flap is tilted by a link 2 and lever 4 in order to produce a positive pressure at the lower end of the gap. Further tilting of the aileron or flap II does not widen the gap. Fig. 3 shows a modification in which the flap II is carried by parallel links 15, 16 hinged to a lever 12, 13 pivoted at 11 to an arm 7 on the planes. The lever 12, 13 is normally held by a spring against a stop 14 so that the flap first moves from the position II to a position IIa as the lever 4 is actuated. Further movement of the lever 4 causes the lever 12, 13 to tilt owing to the link 15 being incapable of further angular movement relative to the lever 12, 13. Two other similar linkages, but involving non‐parallel links, are described which cause an immediate tilting of the flap as well as a translational movement. In one case the gap is kept closed during the initial movement by the flap remaining close against the upper rear edge of the fixed part of the plane. In the other case the lower end of the gap is kept closed by a plate 18, Fig. 4a, urged upwards by a spring when the flap reaches the position IIb. The plate is returned to its normal position by a cam plate 22 on a rod 20 connected to the lever 4 and having a slot 21 moving over the pivot 17 of the plate 18, the plate 22 engaging a projection 19 on the plate 18. Another linkage is described having for its effect a continual widening of the gap as the aileron or flap is tilted. Fig. 7 shows a modification in which an independently operable braking flap 22 is mounted beneath the aileron or flap II. This flap 22 is normally kept against the flap II by a rubber or other spring 23 and is connected by a cable 26 to a spring drum 29 on a lever 30. As the flap II moves rearwardly the cable 26 unwinds from the drum 29 until the flap II is in its extreme position and the drum 29 cannot rotate any further. Movement of the lever 30 then causes the depression of the flap 22 as shown at 221. A telescopic linkage may replace the cable 26 and spring‐drum 29.