US2438942A - Wing air slot - Google Patents

Description

E. H. POLK WING AIR SLOT April 6, 1948.

Filed June 11, 1943 INVENTOR ATTORNEY Patented Apr. 6, 1948 UNITED STATES F F I EK 2,43 94g l 3 1 a WING AIR SLOT Edwin H. Polk, United. States Navy Application June 11, 1943, Serial No. 490 431 2 Claims. (crane-4m (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370

The subject matter of this invention is a means for increasing the lateral stability of an airplane, and more generally for improving the control re sponse of the several airplane control surfaces at reduced flying speeds,

It is well known that the controls in an airplane become sloppy at low flying speeds, particularly when the air speed approaches stalling speed. Especially is this true of the aileron controls, because normally they do not get the benefit of the airstream from the propeller, which is usually mounted on or near the axis of the plane, whereas the ailerons are necessarily located at some distance outboard therefrom.

One of the objects of the present invention is to direct some of the air currents from the propeller airstream outboardly toward the tips of the wings and emit them in the proximity of the ailerons. This and other more specific objects will appear in the following description which is accompanied by the drawing, in which:

Fig. 1 shows a typical airplane wing in plan view, with one form of the means for diverting part of the airstream of the propeller toward the aileron,

Fig. 2 is a front view of the same wing, and

Fig. 3 is a section thereof taken at 3-3 of Fig. 1. Referring to the drawing in which a preferred form of the invention is shown, I represents the wing, 2 its leadin edge, 3 the aileron and t the air duct through the wing, the inlet end of which opens at the leading edge at 5, which is within the area of the propeller airstream, the outer edge of which is approximately indicated by the dot and dash line 6 (Fig. 1). The outlet l I of the air duct constitutes a chamber l2, th'e reversely and inwardly curved contraction l3 thereof having a continuously'tapering top and bottom contour l4 up to the place of connection with a narrow slot 1 in the upper surface of the wing along the front of the aileron. This construction forms an outlet nozzle l5 which is slanted in a direction so as to effect the aileron controls, The wing is shown diagrammatically in the figures and may be constructed in any of the usual forms. It may be of any other shape and dimensions besides that shown here for the purpose of illustration.

Generally the wing will have longitudinal structural beams 9 and it. Preferably the slot l in the upper wing surface will be placed forward of the after beam It, as shown, thereby rendering it unnecessary to pierce the beam to accommodate the air supply duct nor to redesign it to strengthen it at the point of piercing.

The result of diverting a portion of the airstream from the area of the propeller airstream by means of the air duct shown, or any other form of conduit, to the proximity of the aileron, is that the loss of the lateral stability, as the air speed decreases, is delayed, until a lower air speed is reached than would be the case without the provision of this airstream diverting means. Thus the effectiveness of the aileron control is actually increased, particularly at the lower speeds. Normally the wings near the tips tend to stall out at the slower speeds, and it is to delay this stalling action that the slots are placed in the upper wing surfaces so as to emit the air in the direction of the ailerons and thus delay this action. The action may be further delayed to a. certain extent by some slots formed in the wing immediately in front of the forward edge of the aileron, as shown at 8 in Fig. 3, so as to divert some of the air from the under side of the wing up through the wing to the top. over the aileron.

Although only the preferred form of the air ducts and slots is shown, many other arrangements may be used whereby to divert the air from the propeller airstream or some other locations of a higher air speed to the proximity of the control surfaces where the airstream may be much lower at the time when stalling speed is approached.

This invention may be used by or for the Government of the United States for governmental purposes without the payment to me of any royalty thereon or therefor.

What is claimed is:

1. An airplane wing having improved aileron response at low airspeeds, with fore and aft longitudinal beam members tapering toward the outer end of the wing, an aileron hingedto the trailing edge of said wing at its outer end, a slot in the upper surface of the wing ahead of the aft beam member opposite said aileron, a rearwardly directed passage in said wing connected to said slot, an air passage in the propeller slip stream extending from the leading edge of the wing through the thick portion of the fore beam member, and an air conduit from said last named passage to said rearwardly directed passage,

whereby the thinner portion of the aft beam member is not weakened by any passages for the air directed toward the aileron.

2. An airplane wing comprisin a hollow airfoil having a slot extending along a portion of the trailing edge of the airfoil and substantially parallel thereto, means defining an air duct embodled in the airfoil and having an opening confined 3 to and directed through said leading edge to provide an inlet to the air duct, a chamber in the airfoil branching from the air duct to form an outletand being connected with the slot, said chamber being as broad as the slot and having a 113- I ;versely and inwardly curved contraction where it branches from the air duct, merging into a continuously tapering top and bottom contour up to the place of connection with the slot to form an outlet nozzle, and a separate airfoil mounted conr tiguously to the slot and located within the sub -''stantiai confines 01' the wing.

EDWIN H. POLK.

REFERENCES CITED The following references are of record in th Number Number file of this patent: a

Great Britain Mar. 20, 1930

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