NACA-TN-1872

Abstract

INTRODUCTION <br>As a solution to the high-lift and lateral-control problems presented at take-off and landing for transport airplanes and other airplanes having large wing loadings, the National Advisory Committee for Aeronautics has been investigating the characteristics of spoiler-type lateral-control devices to be used in conjunction with full-span flaps. The results of many of these investigations have been summarized in reference 1 and have indicated that, in addition to allowing for the use of full-span or almost full-span high-lift flaps, the spoiler-type, lateral-control devices also provide control at high angles of attack, favorable yawing moments, and higher reversal speeds than conventional flap-type ailerons because of the smaller wing twisting moments of spoiler-type ailerons. In addition, spoiler-type lateral-control devices provide small stick forces and an increased effectiveness when full-span Slaps are deflected, particularly when a plug aileron is used. These investigations have also shown the large increases in wing lift obtainable with a full-span flap, and the generally superior lift and Lateral control characteristics obtainable with a slotted-type flap. The results of other investigations performed on unswept wings having high critical speeds (references 2 to 5) showed the increase in rolling effectiveness of the spoiler-type ailerons when the Mach number was increased in the high Reynolds number range as contrasted to a decrease in rolling effectiveness obtained with conventional ailerons as the Mach number increased. <br>The present investigation was preformed in the Langley 300 MPH 7- by 10-foot tunnel to determine the lift and lateral control characteristics of a moderately thick, low-drag, semispan wing (having NACA 652-215 sections) equipped with a full-span slotted flap and either a plug aileron or a retractable aileron. The present investigation is an extension of the investigations reported in references 4 to 6 and employs the same wing plan form but a thicker wing section than that used in these previous investigations. Wing lift, drag, and pitching-moment characteristics were obtained for the plain wing, and also for the wing with the flap deflected 15&#186;, 30&#186;, and 45&#186;&#160; at various flap positions in order to determine the optimum-lift flap-deflected positions (that is, the flap positions at which optimum lift characteristics were obtained over the angle-of-attack range). Tests of the plug-aileron and retractable-aileron configurations were performed at various aileron projections through an angel-of-attack range with the plain-wing configuration and also with the flapped-wing configuration with the flap at various deflections in the selected optimum-lift positions.