INTRODUCTION
The use of spoilers as lateral-control devices has long been a subject of research for the National Advisory Committee for Aeronautics. Some notable merits of spoilers, such as control at high angles of attack, favorable yawing moments, and the practicable use of full-span flaps with spoiler arrangements, have been known for acme time. In addition, it has been found that spoilers generally provide greater rolling moments when full-span flaps are deflected, particularly when the spoiler moves through an opening (spoiler slot) in the wing. These and other aerodynamic characteristics of spoilers, such as spoiler lag, have been studied and presented in numerous papers. (See references 1 to 5.) Several flight investigations have been made to illustrate the practicability of employing spoilers on airplanes equipped with full-span flaps in Order to secure lateral control (See references 6 to 8.) An investigation reported in reference 9 suggests the use of spoilers in front of ordinary ailerons in order to increase the rolling moments and to decrease the aileron hinge moments in high-speed flight.
The present investigation was made in the Langley300 MPH 7-by 10-foot tunnel to ascertain the effect of spanwise and chordwise location of spoilers on spoiler effectiveness. An attempt is made to determine whether present aileron design data (such as found in reference 5) can be used to design spoiler-type ailerons. Tests were made with a semispan wing of a 50-percent-semispan spoiler varying in position from the 50-percent-chord station to the 80-percent-chord station, whereas other tests included spoilers mounted at the 70-percent-chord station with the spoiler span increasing from 10 percent of the semispan to l00 percent of the semispan in 10 percent increments. Additional tests were made to study the effect of gaps between spoiler segments.