US2444293A - Gap seal for flaps - Google Patents

Description

J1me 1948. o. E. HOLT GAP SEAL FOR FLAPS Filed June 18. 1943 INVENTOR OSCAR E HO ATTORNEY Wi d 9% Patented June 29, 1948 Oscar E. Holt, Ferguson, Mo., assignor to Qurtissa corporation of Dela- Wright. Corporation ware Application-lime 18, 1943, Serial No." 491 401 lhis invention relates to airplanes and more particularly to means for limiting the leakage flow of air in the gap or slot passing between. a stationary lifting structure :or airfoil and a movable control structure, suchas a flap when the movable structure is aligned or relatively undisplaced with respect to the stationary structure.

With the present form of flap arrangements and regardless of the flight attitude assumed by the airplane, when the flaps are moved. into. a neutral 0! up position, there is considerable leakageair which passes through the slot between the stationary-and movable structures regardless of how well the union of the two structures is fashioned. This passage of air through the slot is due to the large differential of pressure between the air on the bottom face oftheliiting structure and the air on the top face of the lifting structure. -At such times, this leakage at the. outlet of the slot does no good since it creates great turbulence over the upper face of the movable structure, resulting in loss of lift and in horse power loss in the propelling of the airplane. Also this air in passing through the slot often deposits ice therebetwee'n causing the movable structure to stick to the stationary structure when its use is desired. In addition to the icefiactuallyprevent ing relative movement of the structures, it will also, by being deposited on the hose face of the control structure, spoil the contour thereover and setup a detrimental turbulence of air.

It is 'anobject of the present invention to provide means which wil'l automatically come intoplay uponthe movable control structure being moved to its position in alignment with the liftlng structure to clcse off the 'airslot between the movable structure and the. stationary structure.

It is another object of the invention to provide a slot closing means which is resilient and adapted to be depressed upon the movable surface being returned to thelevel flight or undis placed position whereby any deviation in tolerances or wear will not greatly afieot the efficiency ofthe slot closing means. r

e According to the present invention there has been provided within the flap arch assembly of the stationary structure, a strip of, resilient material, such as rubber, running coextensively therewith. This resilient material, upon the flap being returned to its up position, is depressed and its shape distorted whereby the engagement of the 'fiap with the same-is positive and the: flow at air is efficiently sealed off; This strip extends only a small distance rearwardly of the air face and not to such an extent as to interfere with 4 Claims. (Cl. 244-42).

the larger flow of: air through thewslott which is desired when the flap is moved: to. its? down or displaced position. a v

For other'obiects and fora. better: understand ing of the invention, reference maybe had tozthe following detailed? description taken. in: connection with the accompanying" drawing; m which;

Fig. 1 is a fragmentary view taken throughazr airtoib section at a pointthereon where the flap is connected. i i l I Figa z' is a perspective view looking atthelface of-the arch assembly of. the stationary: structure and: the strip of sealing material runmngatherealong." Eig. 3is an enlarged sectionalvlew: showing one form of resilient material andwiththis'material depressed due to engagement of the. flap witlr the same to effect thereby .thesealing of the airslot. I i Fig. 4. is a. sectional View of a modified form- 0t resilient material also depressed as when the flap is in its'up positionto close off the airslotr Referring now. particularly to Figs. Lamb 2, there is shown a stationary lifting or wing structure l0 havinganarch assembly H within which. there is: connected a movable control. structure or flap l2; upper face= l3 of :the stationary structure It extends. considerably-rearwardly of a lower face 14 thereof; The'control structure i2? has a: nose portion I 5 and between it and the:

arch assembly N there is, even in the best: of

designs, an :airslot or gap l6 through which-air leaks. This leakage flow of air through theairslot is greatinasmuch as there is a large difference of pressure of the air between the-lower and upper faces of the stationary surfaces"); The velocity of the? air at an outlet l1 atfthe. end of the upper surface 13 is high andz suchiaasuto cause considerable eddyingrot air above rtheiflap with consequent loss of lift.

Themova-ble structure lz is so connectedto the stationary structure by hinge elements. adapted: to extendthrough openings Win the arch assembly' that the movement with thewflap unmovable structure-t2 to its down position causes not; only a downward movement ot' the flap, buta rearward. movement so as to enlarge the width of the slot [.6 whereby a greater fiowof airmay. behadithrough the slot at atime of takeoff or: landing: when such flowais desired over the upper surface of the llapfor its scavenging; action thereon to; increase lifting power thereof. A mechanism for movin the fiapds shown-at l9,;-Fig. I;

in: which there is incorporated a pair of upper and lower links 20 and 2| adapted to be operated section and has its fiat face secured to a wood, backing member 26 which is connected flush with the arch assembly ll. When the movablestructure I2 is in its up position, the nose portion I5 will come into alignment with the strip and' depress the same so that it assumes the distorted form shown :by the full lines in Fig. 3. This is 4 for, wherein the leading edge of the flap is of convex curvature and adapted for nesting in a recess having an upwardly and rearwardly directed surface formed at the trailing edge of the airfoil between the upper and lower surfaces thereof, the flap being movable rearwardly to provide a slot between the airfoil and the flap leading edgefthrough which air may flow upwardly and rearwardly as the flap trailing edge v is lowered and being movable forwardly to close such slot as said trailing edge is raised, the nose ofthe flap leading edge presenting a surface substantially normal to the direction of such for- 'ward movement, and a resilient strip secured desirable to obtain a tight jointat 21 and to positively close off the slot l6.

In Fig. 4, there is shown another form not a strip material which is of similar outside shape as the D-shaped strip 25 but of solid rubber and of such size that the wood'b'acking is not required; As the movable structure I2 is rotated to depress the rubber, portions 29 of the material will. flow along the face of the nose portion l5 thereby enlarging the contacting'area between the resilient material'29 and'the face of the nose portionl5." It should be noted however, that the extent to which these strips of material project rearwardly'of thearch assembly is small compared to'the actual 'dis tancebetween the arch assembly and the nose face of the flap when the flap is in its down position. This extent is thus not such that the-great flow of air which is desired through the slot at times when the flaps are down is 'greatly impeded.

It should now be apparent that there has been provided means for limiting the flow of air through theslot between the stationary structure and the movable structure or flap which automatically comes into play as the movable structure is moved to its up position into alignment'with the stationary structurefi :With such a sealing arrangement, leakage air flow is stopped and the possibility. of ice being disposed in the slot to such aniextent as to cause themovable surface to stick to 'thestationary surface no longer exists, nor will ice be allowed to form'on the nose face ofthe movable structure such as to disrupt the flow of air over the movable structure'surface upon'the same beini 'moved to its down'posi'tionfl While various changes may be made in the detailedconstructiom'it shall be understood that such changes shall be'withi'n'the spirit and scope of the present invention as defined by the appendedclaims. f

I claim as my invention:'

1. In an airfoil and trailingedge flap therefor, wherein the leading edge of the flap is of convex curvature and adapted for nestingin a recess at the trailing edge of 'the airfoil between the upper andlower surfaces thereof, the flap being movable rearwardly to provide'a slot between the airfoil and the flap leading edge as the traili'ng edge of the flap is lowered and'being movable forwardly to close such slot as said trailing edgeis raised, a resilient strip secured along the recess substantially intermediate of said upper and lower surfaces for abutment and compressi on'by the nose of the flap leading edge to seal the "closed slot upon such forward movement.

2. In 'an airfoil and trailing edge flap therealong the recess'for abutment and compression by such flap nose surface to seal the closed slot upon such forward movement.

3. In an airfoil and trailing edge flap therefor, wherein the nose of the flap is of convex curvature and adapted for nesting in a recessed wall at the trailing edge of the airfoil, the flap being movable rearwardly to provide a slot between the airfoil and the flap leading'edge as the flap trailing edge is lowered through which slot air may flow upwardly and rearwarclly, the flap being movable forwardly for nesting to close suchslot as the flap trailing edge is raised, the nose of the flap and said recessed wall of the airfoil having opposed surface portions one of which is substantially normal to the direction of such forward movement, and a resilient strip secured along the other one of said surface portions for abutment and compression by the first mentioned surface portion to seal the closed slot upon such forward movement, theface of the strip exposed to airflow when the slot is open being rounded to facilitate such airflow.

4.111 an airfoil'and trailingedge flap combination, a recess in the trailing edge of the airfoil between its upper and lower surfaces, a surface of convex curvature forming the flap' leading edge, the airfoil and flap being so constructed and arranged that a slot is provided between the airfoil and the flap leading edge by rearward movement of said leading edge when the trailing edge of the flap is lowered and that said flap leading edge moves forward to nest in the recess and close the slot when the trailing edge of the flapis raised, a resilient strip secured along the recess substantially intermediate of said upper and lower surfaces for abutment and compression by said flap leading edgcto'seal the closed slot upon such forward movement.

OSCARE. HOLT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS FOREIGN PATENTS Country Date Great Britain "Sept. 5, 1938 Great Britain May 15, 1940 Germany Feb. 21, 1939 Number Number

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