This report presents the results of an analytical study of the lateral controllability of an airplane in which both the static rolling and yawing moments supplied by the controls and the reactions due to the inherent stability of the airplane have been taken into account. The investigation was undertaken partly for the purpose of coordinating the results of a long series of wind-tunnel investigations with phenomena observed in flight tests; for this reason a hypothetical average airplane, embodying the essential characteristics of both wind-tunnel models and the full-size test airplanes, was assumed for the study.

Weick, Fred E↗

NASA NTRS1937

Resume and analysis of NACA lateral control research

An analysis of the principal results of recent NACA lateral control research is made by utilizing the experience and progress gained during the course of the investigation. Two things are considered of primary importance in judging the effectiveness of different control devices: the (calculated) banking and yawing motion of a typical small airplane caused by a deflection of the control, and the stick force required to produce this deflection. The report includes a table in which a number of different lateral control devices are compared on these bases.

Weick, Fred E↗

NASA NTRS1936

Wind-tunnel tests of wing flaps suitable for direct control of glide-path angle

Preliminary tests have been made for the purpose of obtaining a flap arrangement suitable for direct and immediate control of the steepness of the glide path of an airplane, a use for which present flaps are not satisfactory. An attempt has been made to develop a flap giving a reasonably high maximum lift coefficient with relatively low deflection and maintaining this value of the maximum lift coefficient with a large increase of deflection, the increase in deflection being accompanied by a large increase in drag. An arrangement was found that gave a maximum lift coefficient of approximately 1.90 for all flap deflections between 25 and 80 degrees, within which range the drag of the wing increased regularly to a large value.

Weick, Fred E↗

NASA NTRS1936

Wind-Tunnel Research Comparing Lateral Control Devices Particularly at High Angles of Attack XIII : Auxiliary Airfoils Used as External Ailerons

This is the thirteenth report on a series of systematic tests comparing lateral control devices with particular reference to their effectiveness at high angles of attack. The present wind tunnel tests were made to determine the most feasible locations for lateral control surfaces mounted externally to a rectangular Clark y wing.

Weick, Fred E↗

NASA NTRS1935

Development of the NACA slot-lip aileron

An investigation of the undesirable delayed action, or lag, of the spoiler-type lateral control device led to the development of the NACA slot-lip aileron. The tests were made in the 7- by 10-foot wind tunnel with a 4- by 8-foot wing hinged at the tunnel jet boundary and taken of the motion of the control device under test and of the resulting wing motion. First, the lag, as affected by the fore-and-aft location of retractable ailerons or spoilers was determined. The lag was found to increase regularly as the spoiler was moved from the rear of the wing toward the front. Then a combination of spoilers and fixed slot was developed that, with the spoiler retracting into the forward part of the slot, reduced the time lag to a negligible value. In addition, an arrangement was developed using a hinged aileron-type flap as the upper portion, or lip, of a slot through the wing. This arrangement appears to be usable as a form of lateral control device that shows promise of giving improved control and stability at the high angles of attack through stall, with negligible lag, low control forces, and relatively simple construction.

Weick, Fred E↗

NASA NTRS1935

A Flight Investigation of the Lateral Control Characteristics of Short Wide Ailerons and Various Spoilers with Different Amounts of Wing Dihedral

This report presents the results of flight tests made to determine the lateral control characteristics of short wide ailerons and spoilers, as a consequence of the promise shown in wind-tunnel tests by these devices as means of obtaining lateral control, particularly at angles of attack above the stall. Several forms of spoilers, front-hinge, rear-hinge, plain retractable, and saw-tooth retractable were tested alone and in combination with the ailerons. The tests were made with several different amounts of wing dihedral so that the effect of the yawing moments of the different lateral control combinations, which varied from large negative to large positive values, could be evaluated. In conjunction with the tests, observations were made to throw some light on the feasibility of operating the airplane with two controls instead of the present three.

Weick, Fred E↗

NASA NTRS1935

Wind-tunnel research comparing lateral control devices, particularly at high angles of attack XII : upper-surface ailerons on wings with split flaps

This report covers the twelfth of a series of tests conducted to compare different lateral control devices with particular reference to their effectiveness at high angles of attack. The present wind tunnel tests were made with two sizes of upper-surface ailerons on rectangular Clark Y wing models equipped with full span split flaps. The tests showed the effect of the upper-surface ailerons and of the split flaps on the general performance characteristics of the wings, and on the lateral controllability and stability characteristics. The results are compared with those for plain wings with ordinary ailerons of similar sizes.

Weick, Fred E↗

NASA NTRS1934

Wind-tunnel research comparing lateral control devices, particularly at high angles of attack VI : skewed ailerons on rectangular wings

This report covers the sixth of a series of investigations in which various lateral control devices are compared with particular reference to their effectiveness at high angles of attack. The present report deals with flap-type ailerons hinged about axes having an angle with respect to the leading and trailing edges of the wing. Tests were made on four different skewed ailerons, including two different angles of skew and two sizes of ailerons. At the high angles of attack, all the skewed ailerons tested were slightly inferior with respect to rolling and yawing moments to straight ailerons having the same span and average chord. Computations indicate that the skewed ailerons are also inferior with respect to hinge moments.

Weick, Fred E↗

NASA NTRS1934

Wind-tunnel tests on combinations of a wing with fixed auxiliary airfoils having various chords and profiles

This report presents the results of wind tunnel tests on various auxiliary airfoils having three different airfoil sections and several different chord lengths in combination with a Clark y model wing in a sufficient number of relative positions to determine the optimum with regard to certain criterions of aerodynamic performance. The airfoil sections included a symmetrical profile, one of medium camber, and a highly cambered one. The chord sizes of the auxiliary airfoils ranged from 7.5 to 25 percent of the chord of the main wing, and the span was equal to that of the main wing.

Weick, Fred E↗

NASA NTRS1933

Aerodynamic tests of a low aspect ratio tapered wing with various flaps, for use on tailless airplanes

Wind tunnel tests were made of a model wing having an aspect ratio of 3 and a tapered plan form with a straight trailing edge. The model had the Clark Y airfoil section throughout it's entire span and had no washout, depending on a trailing-edge flap for longitudinal balance and control. The flap had a constant chord and was divided into four equal portions along the span. The tests were made with the entire flap deflected to obtain longitudinal control and balance, and also with the inner portions deflected alone, and with the outer portions deflected alone. It was found that the simple wing with no washout or change of basic section along the span has aerodynamic characteristics well suited for use on tailless airplanes. A higher lift coefficient was obtained with the full-span flap deflected as a unit to give longitudinal balance than was obtained with either the inner or the outer portions of the flap deflected.

Weick, Fred E↗

NASA NTRS1933

Wind tunnel research comparing lateral control devices, particularly at high angles of attack XI : various floating tip ailerons on both rectangular and tapered wings

Discussed here are a series of systematic tests being conducted to compare different lateral control devices with particular reference to their effectiveness at high angles of attack. The present tests were made with six different forms of floating tip ailerons of symmetrical section. The tests showed the effect of the various ailerons on the general performance characteristics of the wing, and on the lateral controllability and stability characteristics. In addition, the hinge moments were measured for the most interesting cases. The results are compared with those for a rectangular wing with ordinary ailerons and also with those for a rectangular wing having full-chord floating tip ailerons. Practically all the floating tip ailerons gave satisfactory rolling moments at all angles of attack and at the same time gave no adverse yawing moments of appreciable magnitude. The general performance characteristics with the floating tip ailerons, however, were relatively poor, especially the rate of climb. None of the floating tip ailerons entirely eliminated the auto rotational moments at angles of attack above the stall, but all of them gave lower moments than a plain wing. Some of the floating ailerons fluttered if given sufficiently large deflection, but this could have been eliminated by moving the hinge axis of the ailerons forward. Considering all points including hinge moments, the floating tip ailerons on the wing with 5:1 taper are probably the best of those which were tested.

Weick, Fred E↗

NASA NTRS1933

Wind-tunnel tests on model wing with Fowler flap and specially developed leading-edge slot

An investigation was made in the NACA 7 by 10 foot wind tunnel to find the increase in maximum lift coefficient which could be obtained by providing a model wing with both a Fowler trailing-edge extension flap and a Handley Page type leading-edge slot. A conventional Handley page slot proportioned to operate on the plain wing without a flap gave but a slight increase with the flap; so a special form of slot was developed to work more effectively with the flap. With the best combined arrangement the maximum lift coefficient based on the original area was increased from 3.17, for the Fowler wing, to 3.62. The minimum drag coefficient with both devices retracted was increased in approximately the same proportion. Tests were also made with the special-type slot on the plain wing without the flap. The special slot, used either with or without the Fowler flap, gave definitely higher values of the maximum lift coefficient than the slots of conventional form, with an increase of the same order in the minimum drag coefficient.

WING SLOTS & FLAPS, FOWLER↗

NASA NTRS1933

Wind tunnel research comparing lateral control devices, particularly at high angles of attack X : various control devices on a wing with a fixed auxiliary airfoil

Results are given of a series of systemic tests comparing lateral control devices with particular reference to their effectiveness at high angles of attack. These tests were made with two sizes of ordinary ailerons and different sizes of spoilers on a Clark Y wing model having a narrow auxiliary airfoil fixed ahead and above the leading edge, the chords of the main and auxiliary airfoils being parallel. In addition, the auxiliary airfoil itself was given angular deflection. The purpose was to provide rolling moments for lateral control. The tests were made in a 7 by 10 foot wind tunnel. They included both force and rotation tests to show the effect of the devices on the lift and drag characteristics of the wing and on the lateral stability characteristics, as well as lateral control. They showed that none of the aileron arrangements tried would give rolling control of an assumed satisfactory value at all angles of attack up to the stall. However, they would give satisfactory values, but at the expense of abnormally high deflections and very heavy hinge moments. The most effective combination of ailerons and spoilers gave satisfactory values of rolling moment at angles of attack below the stall, and the values did not fall off as rapidly above the stall as with ailerons alone. With an arrangement of this type having the proper relative proportions and linkage, it should be possible to obtain reasonably satisfactory yawing moments and control forces. Deflecting one-half of the auxiliary airfoil downward for the purpose of control gave strong favorable yawing moments at all angles of attack, but gave very small rolling moments at the low angles of attack.

Weick, Fred E↗

NASA NTRS1933

Wind tunnel research comparing lateral control devices, particularly at high angles of attack VIII : straight and skewed ailerons on wings with rounded tips

Tests showed the effect of the ailerons and the tip shapes on the general performance of the wing, as well as on the lateral control and stability characteristics. The hinge moments were not measured but the approximate values are given in the first report of the series.

Weick, Fred E↗