No. 2, 11 1/2-ft wind-tunnel tests of a small span, small chord double aileron for use as a lateral control on a high-lift aircraft

Abstract

Tests were made on a 1/2.25 scale model of a half wing of the Master. The span of the aileron was 0.22s and the chords were 0.2c and 0.15c; the aileron was fitted with a balance tab of 0.05c chord. Measurements were made of the hinge moments, lift increments (from which the rolling moments were deduced) and the pressures in the aileron gaps just above and below the seals. The latter were required for estimating the effect of internal shrouded nose (or pressure) balances. Tests were also made of the effect on the hinge and rolling moments of a small spoiler situated just aft of the front aileron vent ; the spoiler was assumed to emerge on the lower surface of the down-going aileron and on the upper surface of the up-going aileron. The main conclusions are: (1) A double aileron will give much the same rolling moment as a single aileron of the same total chord and at the same total deflection. (2) The double aileron offers no advantage where total deflections of magnitude not greater than about 20 deg are required (as for ailerons of normal span and area). For ailerons of small span and chord, for which deflections of the order of 50 deg are required, the double aileron offers definite advantages over the single aileron. (3) An inter-aileron gearing of about 2 is probably the optimum. (4) For a representative carrier-borne aircraft it is estimated that, even with this inter-aileron gearing, either the tab balance plus a nose balance of upwards of 40 per cent or a nose balance approaching 50 per cent is required to keep the stick forces for full control at landing speeds down to an acceptable figure. (5) The effect of the spoiler is only apparent for control movements of less than about 20 deg. Its possibilities on ailerons of normal span and angular range are worth investigating.