US2005965A - Airfoil control means - Google Patents

Description

' June 25, 1935. G. E. BARNHART AIRFOIL CONTROL MEANS Filed July 5, 1935 2 Sheets-Sheet l INVEZNTOR GEORGE E. BAENHAQT '7 fiaaxl ATTORNEY June 25, 1935. G. E. BARNHART AIRFOIL CONTROL MEANS Filed July 5, 1953 2 SheetsSheet 2 GEORGE E. BARNHAQT ATTORNEY Patented June 25, 1935 UNITED STATES PATENT OFFICE 35 Claims.

This invention has to do in a general way with the art of aviation, and is more particularly related to improved means for governing the flow of air over the airfoil surfaces so as to facilitate the control of the airplane. In other words, my invention contemplates means of controlling the lift and drag of the airfoil surface and incorporates a novel type of vane construction whereby such control can be conveniently and efficiently effected with great sensitivity.

The advantages of a structure of this nature will be immediately apparent to those familiar with the art. It permits skillful maneuvering of the aircraft without excessive danger since the control can be employed to quickly bring the airplane out of a stall or spin. The craft can be flown in severe weather conditions without the usual hazards. The invention also permits and contemplates the use of a thin high-speed airfoil section which will travel through the air with the lowest possible resistance, such section being provided with a movable vane or vanes which canbe extended from the airfoil section into the air stream at the will of the pilot to produce what is, in effect, a change in camber of the airfoil section.

It is one object of this invention to produce a device of the class described which can be employed to change the lift and drag characteristics individually or simultaneously on one surface without changing such characteristics on the opposite surface.

It is a further object to provide the device with means whereby the lift and-drag characteristics can be simultaneously or individually changed on both surfaces and in which changes can be effected independently in the different airfoils to permit lateral control.

It is another object of this invention to provide a novel type of vane structure wherein the vanes are operable toward the airstream. In other words, it is an object of this invention to produce a novel type of vane construction which is hinged at or near its trailing. edge. Such vanes may of course be used in combination with vanes hinged at their leading edge and also away from the. airstream for the production of novel control features.

It is a further object of this invention to produce a flap or vane structure of the class described in which a tension system is employed for both opening and closing the flaps or vanes.

It is a further important feature of the invention that the flaps or vanes are constructed 'so that there will not be any material "leakage of air through the joint or hinged portion which might spoil the air conditions on the opposite side. In a modified form of my invention, however, I contemplate a device in which the air stream which washes off the underside of the flap is carried through the airfoil section to the opposite side thereof.

It is a still further object of this invention to incorporate flaps or vanes of the type just referred to in the tail structure of an airplane, providing a novel type of rudder and a novel type of elevator.

In one of its forms, my invention contemplates an arrangement of flaps or vanes extending lon gitudinally of the wing section, such vanes being arranged so as to wash the air stream toward the central portion of the wing.

In another form of my invention, I arrange the flaps or vanes so that the air stream is washed away from the central portion of the wing toward its two edges, that is, toward the fuselage and toward the tip.

As was pointed out above, it is one object of this invention to provide flaps or vanes hinged at their trailing edges so as to swing into the air stream, and, since the air pressure on such vanes understood from the following description of the.

accompanying drawings which are chosen for illustrative purposes only, and in which- Fig. 1 is an elevational view showing an airplane equipped with certain embodiments of my invention;

Fig. 2 is a plan view partly broken away showing an airplane, and further illustrating certain embodiments of my invention;

Fig. 3 is a plan view similar to Fig. 2 but showing a somewhat different arrangement of th flaps and the wing shape;

Fig. 4 shows an airfoil section of the type shown in either Fig. 2 or Fig. 3 equipped with one preferred form of control mechanism contemplated by this invention;

Fig. 5 shows another airfoil section of the general character shown in Fig. 2 or Fig. 3 equipped with another preferred form of control mechanism contemplated by this invention;

Fig. 6 shows another airfoil section and illustrates another arrangement of control flaps or 'vanes contemplated by this invention;

Fig. is a fragmentary view showing the trail ing edge of an airfoil section equipped with another modified form of the invention; and

Fig. 8 is a sectional view showing a trailing edge portion of another airfoil section equipped with a modified form of the invention.

More particularly describing the invention as herein illustrated, reference numeral N indicates a fuselage of an airplane which is equipped with a landing gear l2, wings l3, and a tail structure l4.

Referring first to the tail structure [4 as shown in Figs. 1 and 2, it was pointed out above that this invention contemplates a novel type of rudder and elevator control, such control being shown as comprising a rudder fin l5 which is equipped with a pair of vanes l6 and I6 hinged to the fin at their trailing edges and adapted to have their leading or forward edges swung outwardly into the air stream. The actuation of these vanes may be effected in any preferred manner. For the purpose of illustration, I show the vanes as being mounted upon vertical shafts l1 and H, such shafts having cross members I8 and E8 on their lower ends, the cross members in turn being actuatedby tension members l9 and I9.

In addition to the rudder, the tail structure incorporates a stabilizer or horizontal airfoil section 20, and this section is provided with vanes 2| and 2|" located in opposite sides of the center line of the fuselage and hinged to the stabilizer 20 at their trailing edges. These vanes are adapted to be independently operated so as to swing their leading edges up into the air stream away from the airfoil section.

Although Figs. 1 to 3 inclusive are provided primarily for the purpose of illustrating the tail structure and the general arrangement of the airplanes, I have illustrated in Fig. 1, one type of vane which I propose to use in the wings of the airplane, such vane, indicated by reference numeral 22, is shown as being hinged at its trailing edge adjacent the trailing edge of the airfoil or wing 13 and is adapted for downward swinging movement from its leading edge into the airstream. A vane of this type may be used independently or may be employed in conjunction with various other vanes of types which will be hereinafter described in Figs. 4 to 8 inclusive. However, there are two features in this connection, illustrated in Figs. 2 and 3, which may be employed with vanes of this type or which may be incorporated in the various vanes shown in Figs. 4 to 8 inclusive to give somewhat different control efiects, depending upon the purpose for which the aircraft is designed. I

In Fig. 2 the wing or airfoil [3a is shown as having a leading edge 25 which is substantially normal to the fuselage and the trailing edge 26 which converges from the fuselage toward the leading edge of the wing. It will be observed from Fig. 2 that the flap or vane is divided in three segments indicated at 22a, 22b, and 220. The inner segment or vane 22a is arranged with its leading edge converging from the fuselage toward the trailing edge of the wing, the intermediate vane 2222 has its trailing edge substan tiallyparallel with the trailing edge of the wing, and the outer or tip vane 22c is arranged with its leading edge converging from the tip of the wing toward the trailing edge of the wing or toward the leading edge of the intermediate vane.

In the form shown in Fig. 3, the wing or airfoil |3b has its trailing edge 26?) substantially normal to the axis of the fuselage, and its leading edge 25b converging from the fuselage toward the trailing edge. In this form of my invention, thevane sections 22d and 22; on the extremities of the wing have their greatest width at the edges adjacent the intermediate vane section 22c. In other words, the vane 22d converges from the intermediate vane 22c toward the trailing edge as it approaches the fuselage, and the outer or tip vane section 221 converges toward the trailing edge of the wing as it approaches the tip.

It is to be understood that the features just described in connection with the vanes and the positions of their edges relative to the edges of the wings may be varied and incorporated in the various types of vane structures which will now be described in connection with Figs. 4 to 8 inclusive and that they may be employed on the upper air foil surface independently of or in conjunction with vanes on the bottom surface.

As a further modification of the forms shown in Figs. 2 and 3, I may employ a conventional type aileron at the trailing edge of the wing with a vane-or vanes interposed between the aileron and the fuselage or between the aileron and the tip of the wing, depending upon the location of the aileron.

In Fig. 4, I show an airfoil section indicated by reference numeral 30 which may be of any standard type, and, while it is shown as being a relatively thick section, it is to be understood that, the control structure shown therein as well as the structure shown in Figs. 5 to 8 inclusive is more especially adapted for use in connection with an extremely thin section designed for high speed.

The wing section 30 comprises a front spar 3|, a rear spar 3|, and a skin or covering 32. Reference numeral 33-indicates a vane or flap which is hinged at its trailing edge as indicated at 34 to the undersurface of the airfoil section 30 at a point which is adjacent and slightly ahead of the trailing edge of such airfoil section. This flap or vane 33 is, therefore, designed so that its-leading edge may be swung downwardly into the airstream to occupy the broken line position shown, or any position intermediate the broken line position and the full line position. It will be observed that in this latter position the flap or vane constitutes a segment of the airfoil surbroken link is adapted to be opened by means of a tension member such as a cable 31 extending over suitable pulleys 38 shown as being mounted on the spars and to an actuating mechanism such as a lever or wheel (not shown) located in the cockpit. 1

For the purpose of closing the vane 33, I provide another tension member 39 secured to the leading edge of the vane 33 and extending over guide pulleys 40 to the cockpit (not shown) where it is either connected to the same control, just referred to, or is provided with another control. As was pointed out above, in the operation of a vane of this character it may be difiicult to initiate the opening movement of the vane, and for the purpose of starting this movement I provide a secondary or auxiliary vane 42 hinged at its leading edge as indicated at 43 and having its trailing edge in juxtaposed relation with the leading edge of the vane 33. With this construction, when the vane 42 is opened by means of the tension mechanism, generally indicated at 44, it

is effective to direct the air stream away from the undersurface of the vane 33, thereby creating a reduced pressure area into which the vane 33 may be easily drawn.

For the purpose of the counteracting the effect of the vane 33 when it is extended in increasing the lift on the airfoil section, and, further for the purpose of cooperating with the vane 33 in increasing the drag on the airfoil section, I provide the top surface of the section 32 with a secondary vane 46 which is shown as being hinged at its trailing edge to the top surface of the airfoil at a point situated a substantial distance ahead of the trailing edge of the airfoil. This vane is provided with a control mechanism similar to that described in connection with the vane 33, such control mechanism being indicated by reference numeral 41. In this control mechanism, however, the broken link is employed to retract the vane into its normal position. The reduced air pressure on the uppersurface of the wing may be employed to open the vane, or I may employ a tension spring 48 interposed between the pivot point of the broken link and the rear spar 3|.

In Fig. 5, I show another form of airfoil construction which is designed to giveeven greater flexibility of control than the structure shown and described in connection with Fig. 4. In this figure, the airfoil is shown as comprising spars 3la, 3la, and a skin or covering 32a. In this form of my invention, I provide the undersurface of the airfoil with a pairor set flaps or vanes which are shown as being hinged to the airfoil at their adjacent edges. In other words, the forward flap or vane 50 is hinged at its trailing edge as indicated at and the aft flap or vane 52 is hinged at its leading edge as indicated at 53. The uppersurface of the airfoil is provided with a similar pair or set of vanes. indicated at 54 and 55,

the vane 54 being hinged at its trailing edge as indicated at 56, and the vane 55 being hinged at its leading edge as indicated at 51.

The vane 50 is provided with a control mechanism generallyindicated at 58; the vane 52 is provided with a control mechanism generally indicated at 59; the vane 55 is provided with a. control mechanism generally indicated at 8B; and the vane 54 is provided with a control mechanism indicated at 6|, such control mechanisms being similar to that described in connection with the vane 33 in Fig. 4.

Reference numeral 62 indicates an auxiliary control vane similar injunction and operation to the vane 42 described in Fig. 4. In this connection, it should be pointed out that for most eflicient operation, I have found that the vanes. which are provided on the undersurface of the airfoil and are hinged at or near their trailing edges, should be of a width not substantially less than one-fifth the chord of the airfoil.

With regard to Fig. 5, it will be understood that any one of the vanes may be used independently to produce its given function or that any combination of vanes may be extended at equal or varying angles to produce corresponding variations in the lift and drag characteristics of the airfoil section.

In Fig. 6, I show still another form which my inventionmay take, and in this figure the airfoil, indicated generally by reference numeral 10, is provided with a flap or vane ll hinged at its trailing edge as indicated at 12 and positioned with its trailing edge a substantial distance ahead of the trailing ,edge of the airfoil and with its leading edge I3 a slight distance behind the leading edge of the airfoil.

In this form, the leading edge of the vane is shown as being positioned adjacent the front spar The vane 1| is provided with an opening mechanism generally indicated at I5 and a closing mechanism indicated at 16. In connection with this vane, I show the trailing edge of the airfoil as being provided with a novel type of aileron which is shown as comprising a vane I1 which is pivoted to swing about an axis 18 situated between its two edges. The vane 11 is shaped to conform with the streamline of the airfoil section, and is constructed so that the portion 19, which extends ahead of the axes and which I may hereinafter refer to as a lip, normally forms a part of the upper surface of the airfoil. This vane or aileron is operated by a tension control means of the type described in connection with Fig. 4, such control means being indicated by reference numeral 80.

In Fig. 7, I show another modified form of vane-aileron construction in which the vane indicated by reference numeral 82 is pivoted on an axis 83 in the trailing edge portion of the airfoil section 84. This vane, like the one described in connection with Fig. 6, is shaped to conform with the streamline of the airfoil section, and is provided with a wide vane portion 85, normally formingapart of. the undersurface of the airfoil, such vaneportion preferably being of a width which is not substantially less than one-fifth the chord of the airfoil. Control means, generally indicated by reference numeral 86, is provided for the purpose of actuating this vane.

In Fig. 8, I show still another form which may be taken by my invention, such form comprising an airfoil section generally indicated by reference numeral 90 which has a vane 9| hinged at its trailing edge in the undersurface of the airfoil section. In this construction, I propose to direct a portion of the air, received in the pocket formed by the downward extension of the vane, upwardly through the wing to the upper-surface thereof where it may be used to change. the lift action. For this purpose I provide, what I may term, a confined slot 92 which is in the nature of an elongated box mounted in the airfoil with its lower open end terminating above the vane 9|.;-

On the uppersurface of the wing above the top opening of the confined slot or box 92, I may provide another vane 93 which is shown as being pivoted at its trailing edge as indicated at 94 so as to normally close the opening ofthe confined slot and which may be opened to permit the free movement of the air through the slot and onto the top surface of the wing. The control mechanism for the bottom vane is indicated by reference numerals 95 and 95' and the tension control for the top vane is indicated by reference numeral 96.

It will be apparent from the foregoing description that my invention contemplates means for positively controlling the lift and drag on airfoil surfaces, and it should be pointed out that the vanes or flaps may be operated independently of each other to bring about any desired control in the action of an aircraft about env one or all of its three axes of movement. I may also balance theaction of the various vanes by connecting the controls of the vanes at any desired point, preferably in the cockpit of the airplane. For example, the controls of vanes and 52 in Fig. 5 may be connected so as to balance one of these vanes against the other, thereby adding to the ease with which they may be operated.

It is to be understood that, while I have herein described and illustrated one preferred form of my invention, the invention is not to be limited to the precise construction as described above, but includes within its scope whatever changes fairly come within the spirit of the appended claims.

I claim as my invention:

1. For use in controlling an airplane the combination of: an airfoil having a leading edge and a trailing edge; a vane hinged at its trailing edge to the trailing edge of said airfoil and normally forming a segment of the surface of said airfoil; and shiftable means operable independently of said vane for directing the airstream'across said vane so as to form a reduced pressure area along said vane thereby swinging said vane outwardly at an angle with said airfoil into the airstream.

2. For use in controlling an airplane the combination of: an airfoil having a leading edge and a trailing edge; a vane hinged at its trailing edge to the trailing edge of said airfoil and normally forming a segment of the surface of said airfoil; and shiftable means operable independently of said vane for directing the airstream across said vane so as to form a reduced pressure area along said vane thereby swinging said vane outwardly at an angle with said airfoil into the airstream, said vane being of a width not substantially less than one-fifth the chord of the airfoil.

3. For use in controlling an airplane the com-'- bination of: a cambered airfoil having a leading edge, a trailing edge, and top and bottom surfaces; a vane hinged at its rear edge to said airfoil and normally forming a part of the lower surface; shiftable means operable independently of said vane and adapted to act upon the airstream to form a reduced pressure area along said vane for swinging the front edge of said vane downwardly away from said lower surface so as to set said vane at an angle with said lower surface; and tension means for retracting said vane into said lower surface and holding same in various positions of adjustment.

4. For use in controlling an airplane the combination of: a cambered airfoil having a leading edge, a trailing edge, and top and bottom surfaces; a vane hinged at its rear edge to said lower surfaceTa second vane hinged at its rearedge to said airfoil and normally forming a part of the upper surface thereof; and means for swinging the front edge of said upper vane upwardly away from said upper surface so as to set the same at an angle with said upper surface.

5. For e in controlling an airplane the combination of: an airfoil; a vane hinged at its trailing edge to said airfoil and extending longitudinally thereof, said vane normally forming a part of the surface of said airfoil; and means for swinging the leading edge of said vane outwardly' into the air stream, said last mentioned means including a secondary vane hinged at its leading edge to said airfoil with its trailing edge in substantially juxtaposed relation with the leading edge of said first mentioned vane.

6. For use in controlling an airplane the combination of: an airfoil; a pair of vanes mounted in said airfoil and normally forming a segment of the surface thereof, said vanes being extended longitudinally of said airfoil and hinged to said airfoil at their adjacent edges so that the leading edge of the forward vane and the trailing edge of the aft vane is adapted for outward swinging movement into the airstream; means at the leading edge of said forward vanefor directing the airstream to form a reduced pressure area below said forward vane whereby said forward vane is projected into the airstream; and manually movable means for actuating said aft vane.

7. For use in controlling an airplane the combination of: a cambered airfoil; a set of longitudinally extending vanes mounted on the top surface of said airfoil; another set of longitudinally extending vanes mounted on the bottom surface of said airfoil, all of said vanes normally forming segments of the corresponding airfoil surfaces, and the vanes in each set being hinged to said airfoil at their adjacent edges so that the leading edge of the forward vane in each set is adapted for outward movement intothe airstream and the trailing edge of the aft vane in each set is adapted for outward movement into the airstream; and means for independently actuating said vanes.

8. An airplane of the class described embodying: a fuselage; wings on said fuselage formed with their trailing edges converging fromthe fuselage toward the tip of the wing; and a plurality of vanes hinged at their trailing edges to the trailing edge of each wing, the leading edge of the inner vane on each wing converging from a point near the fuselage toward the trailing edge of the wing and the leading edge of the outer vane on each wing converging from the tip of the wing toward the trailing edge of the wing.

9. An airplane of the class described embodying: a fuselage; wings on said fuselage having their trailing edges substantially normal to the axis of said fuselage and their leading edges converging from said fuselage toward their trailing edges; and means for controlling the airflow relative to said wing, said last mentioned means comprising an inner vane on each wing adjacent the fuselage, an outer vane on each wing adjacent each tip, and an intermediate vane on each wing between the inner and outer vanes, all of said vanes being hinged at their trailing edges to the trailing edges of said wing, and-the leading edges 'of said inner and outer vanes. converging from a point adjacent the leading edge of said intermediate vanes toward the trailing edges of said wing.

10. An airplane of the class described embodying: a fuselage; wings on said fuselage formed with their trailing edges converging from the fuselage toward the tips of the wings; a plurality of vanes hinged at their trailing edges to the trailing edges of each wing, the leading edge of the inner vane converging from a point near the fuselage toward the trailing edge of the wing and the leading edge of the outer vane converging from the tip of the wing toward the trailing edge of the wing; and means including secondary vanes hinged at their leading edges to said wing with their trailing edges in substantially juxtaposed relation with the leading edges of said first mentioned vanes for swinging the first mentioned vanes downwardly into the airstream.

11. An airplane of the class described embodying: a fuselage; wings on said fuselage having their trailing edges substantially normal to the axis of said fuselage and their leading edges converging from said fuselage toward their trailing edges; means for controlling the airflow relative H to said wing, said last mentioned means comprising an inner vane on each wing adjacent the fuselage, an outer vane on each wing adjacent each tip, and an intermediate vane on each wing between the inner and outer vanes, all of said vanes being hinged at their trailing edges to the trailing edges of said wing, and the leading edges of said inner and outer vanes converging from a point adjacent the leading edge of said intermediate vanes toward the trailing edges of said wing; and means for swinging the leading edges of said vanes outwardly into the airstream, said last mentioned means including a plurality of secondary vanes hinged at their leading edges to said airfoil with their trailing edges in substantially juxtaposed relation'with the respective leading edges of said first mentioned vanes.

12. An airplane of the class described embodying: a fuselage; wings on said fuselage formed with their trailing edges converging from the fuselage toward the tips of the wings; and a plurality of vanes hinged at their trailing edges to the trailing edge of each wing, the leading edge of the inner vane on each wing converging from a point near the fuselage toward the trailing edge of the wing.

13. An airplane of the class described embodying: a fuselage; wings on said fuselage formed with their trailing edges converging from the fuselage toward the tips of the wings; and a plurality of vanes hinged at their trailing edges to the trailing edge of each wing, the leading edge of the outer-vane on each wing converging from the tip of the wing toward the trailing edge of the wing.

14. An airplane of the class described embodying: a fuselage; wings on said fuselage having their trailing edges substantially normal to the axis of said fuselage and their leading edges converging from said fuselage toward their trailing edges; and means for controlling the airflow relative to saidwing, said last mentioned means comprising an inner vane on each wing adjacent the fuselage, an outer vane on each wing adjacent each tip, and an intermediate vane on each wing between the inner and outer vanes, all of said vanes being hinged at their trailing edges to the trailing edges of said wing, and the leading edges of said innejfevanes converging from a point adjacent the leading edge of said intermediate vanes toward the trailing edges. of said wing.

15. An airplane of the class described embodying: a fuselage; wings on said fuselage having their trailing edges substantially normal to the axis of said fuselage and their leading edges converging'from said fuselage toward their trailing edges; and ineans for controlling the airflow relative to said wing, said last mentioned means comprising an inner vane on each wing adjacent the fuselage, an outer vane on each wing adjacent each tip, and an intermediate vane on each wing between the inner and outer vanes, all of said vanes being hinged at their trailing edges to the trailing edges of said wing, and the leading edges of said outer vanes converging from a point adjacent the leading edge of said intermediate vanes toward the trailing edges of said wing.

16. For use in controlling an airplane the combination of: a cambered airfoil having a leading edge, a trailing edge, and top and bottom surfaces; a vane hinged at its rear edge to said airfoil and normally forming a part of the lower surface; means for swinging the front edge of said vane downwardly away from said lower surface; a second vane hinged at its rear edge to said top surface; means for swinging the front edge of said second vane into the airstream; a substantial air seal between said vanes, and means for holding said vanes in various positions of adjustment, said top vane being of substantially less width than said bottom vane.

1'7. For use in controlling an airplane the combination of a cambered airfoil having a leading edge, a trailing edge, and top and bottom surfaces; a vane hinged at its rear edge to said airfoil and normally forming a part of the lower surface; means including an auxiliary vane adapted to act upon the airstream to form a reduced pressure area along said vane for swinging the front edge of said vane downwardly away from said lower surface; a second vane hinged at its rear edge to said top surface; means for swinging the front edge of said second vane into the airstream; and means for holding said vanes in various positions of adjustment, said top vane being of substantially less width than said bottom vane.

18. For use in controlling an airplane the combination of a cambered airfoil having a leading edge, a trailing edge, and top and bottom surfaces; a vane hinged at its front edge to said airfoil and normally forming a part of the lower surface; means for swinging the rear edge of said vane downwardly away from said lower surface; a second vane hinged at its rear edge-to said top surface; means independent of said first vane operating means for swinging the front edge of said second vane into the airstream; a substantial air seal between the surfaces containing said vanes and means for holding said vanes in various positions of adjustment, said top vane being of substantially less width than said bottom vane.

19. For use in controlling an airplane the combination of: a cambered airfoil having a leading edge, a trailing edge, and top and bottom surfaces; a vane hinged at its rear edge to said airfoil and normally forming a part of the lower surface; means for swinging the front edge of said vane downwardly away from said lower surface; asecond vane hinged at its front edge to said top surface; means for swinging the rear edge of said second vane into the airstream; a substantial air seal between said vanes and means for holding said vanes in various positions of adjustment, said top vane being of substantially less width than said bottom vane.

20. For use in controlling an airplane the combination of: a cambered airfoil having a leading edge, a trailing edge, and top and bottom surfaces; a'vane hinged at its front edge to said airfoil and normally forming a part of the lower surface; means for swinging the rear edge of said vane downwardly away from said lower surface; a second vane hinged at its front edge to said top surface; means for swinging the rear edge of said second vane into the airstream; and means for holding said vanes in various positions of adjustment, said top vane being of substantially less -width than said bottom vane.

21. For use in controlling an airplane the combination of: a cambered airfoil having a leading edge, a. trailing edge, and top and bottom surfaces; a vane hinged at its trailing edge to the rear half of said airfoil and normally forming a part of one of said airfoil surfaces; and means for actuating said vane, said vane being of a width such that its leading edge does not extend forwardly beyond the center of said airfoil.

22. For use in controlling an airplane the combinationof: a cambered airfoil having top and bottom surfaces; a bottom vane hinged at its rear edge to said bottom surface; means including an auxiliary vane adapted to act upon the airstream to form a reduced pressure area along said bottom vane for swinging said bottom vane downwardly into the airstream; a top vane hinged to said top surface; and meansfor actuating said top vane independently of said bottom vane.

23. For use in controlling an airplane the combination of: a cambered airfoil having top and bottom surfaces; a bottom vane hinged at its rear edge to said bottom surface; means for swinging said bottom vane downwardly into the airstream; a top vane hinged to said top surface; and means for actuating said top vane independently of said bottom vane.

24. For use in controlling an airplane the combination of: a cambered airfoil having a leading edge, a trailing edge, and top and bottom surfaces; a vane hinged at its rear edge to said airfoil and normally forming a part of the lower surface; means for swinging the front edge of said vane downwardly away from said lower surface; a second vane hinged at its rear edge to said top surface; means for swinging the front edge of said second vane into the airstream; and means for holding said vanes in various positions of adjustment, said top vane being of substantially less area than said bottom vane.

25. For use in controlling an airplane the combination of: a cambered airfoil having a leading edge, a trailing edge, and top and bottom surfaces; a vane hinged at its front edge to said airfoil and normally forming a part of the lower surface; means for swinging the rear edge of said vane downwardly away from said lower surface; a second vane hinged at its rear edge to said top surface; means for swinging the front edge of said second vane into the airstream; means for holding said vanes in various positions of adjustment, said top vane being of substantially less area than said bottom vane; and a substantial air seal between said top and bottom vanes.

26. For use in controlling an airplane the combination of: a cambered airfoil having a leading edge, a trailing edge, and top and bottom surfaces; a vane hinged to one surface of said airfoil so that its leading edge may be swung. into the airstream; and means for swinging the leading edge of said vane into the airstream comprising an auxiliary vane hinged ahead of said first mentioned vane to the same surface of said airfoil which carries said first mentioned vane whereby the outward movement of said auxiliary vane into the airstream will form a reduced pressure area over said first mentioned vane.

2'7. For use in controlling an airplane the combination of: a cambered airfoil having a leading edge, a trailing edge, and top and bottom surfaces; at vane hinged at its trailing edge to said airfoil and normally forming a part of one of said airfoil surfaces; and means for actuating said vane, said vane being shaped and positioned so that the distance from its leading edge to the trailing edge of the wing section immediately behind the vane gradually increases throughout the entire span of the vane, and said vane further being of a width not greater than one halfthe chord of the airfoil at any section along its length.

28. For use in controlling an airplane the combination of: a cambered airfoil having a leading edge, a trailing edge, and top and bottom surfaces; a. plurality of vanes hinged at their rear edges to the underside of said airfoil and normally forming a part of the bottom surface thereof, one of said vanes being shaped and positioned so that the distance from the leading edge of such vane to the trailing edge of the wing section immediately behind such vane increases throughout the span of the said vane; and means for actuating said vanes independently of each other.

29. An airplane of the class described embodying: a fuselage; wings in said fuselage; a plurality of vanes hinged at their trailing edges to the trailing edges of each wing, the leading edge of each outer vane converging from the tip toward the trailing edge of the wing; and means for actuating said vanes independently of each other.

30. An airplane of the class described embodying: a fuselage; wings on said fuselage; a plurality of-vanes hinged at their trailing edges to the trailing edges of said wings, the leading edge of each outer vane converging from its inner end toward the trailing edge of the wing; and means for actuating said vanes independently of each other.

31. For use in controlling an airplane, the combination of: a cambered airfoil having a leading edge, a trailing edge, and top and bottom surfaces; a vane hinged to the rear half of the undersurface of sad airfoil so that the training edge may be swung downwardly away from said airfoil;

another vane hinged to the rear half of said upper surface so that its leading edge may swing upwardly away from said airfoil; and means for actuating said vanes.

32. For use in controlling an airplane, the combination of: an airfoil section having a leading edge, a trailing edge, and top and bottom surfaces; a pair of vanes hinged to the top surface of said airfoil so that the leading edge of one and the trailing edge of the other may be swung upwardly into the airstream; another vane hinged to the bottom surface of said airfoil so that its trailing edge may be swung downwardly into the airstream; and means for actuating said vanes.

33. For use in controlling an airplane, the combination of an airfoil section having a leading edge, a trailing edge, and top and bottom surfaces; a pair of vanes hinged to the top surface of said airfoil so that the leading edge of one and the trailing edge of the other may be swung upwardly into the airstream; another vane hinged to the bottom surface of said airfoil so that its leading edge may be swung downwardly into the airstream; and means for actuating said vanes.

34. For use in controlling an airplane, the combination of: an airfoil section having a leading edge, a trailing edge, and top and bottom surfaces; a pair of vanes hinged to the bottom surface of said airfoil so that the leading edge of one and the wardly into the airstream; another vane hinged.

to the top surface of said airfoil so that its leading edge may be swung upwardly into the airstream; and means for actuating said vanes.

GEORGE E. BARN HART.

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