US1918536A - Aeroplane wing - Google Patents

Description

July 18, 1933. v R. w. GRISWOLD, 20 1,918,536

AEROPLANE WING Filed Oct. 17, 1929 al ay ,9

. IN VENTOR.

Q35 JZ j J I l Y ATTORNEYS.

Patented July 18, 1933] v 1 r 1 benk f RIswo n ornLi cj i fi-I r c i it i o it AE ltoriiAnnw fid A v a it Aiipficafiifileviimbef 1925- Q i l' ie-14 0,19? i a a ticularly if a'jplurality l are irued for accomplishing the purpose. The complica tionof structure and consequent increase in 1 This; invention is directed to improving aeroplanes with the purpose of making them a 35 has been proposed more safe, particularly as to the disastrous} v r weight defeats itspracticability. 'This manner of structure, however, has been results arising from stalling,orloss of lifti The lift'of an aeroplane, as iswell known,

is due to the Variations of air pressure above and'below the wing and thisvaries'with the angle ofattack-andalso asthejsqu'are of the c speed of the plane. Up to a certain point-the lifting powerincreases as'the angle of attack isincreased, but as this angle is inereased a critical point is reached as between the angle of attack and the speed of the planewhere the "lifting power practically ceases and disaster usually follows. this condition when it happens close to the ground. "The greater portion of the lifting powerof the aeroplane wing is believed-to be duetothe' reduced pressure above the wing, this reduced pressure being included in whatis usually called the boundary layer above the wing.-flThis re-;

duced pressure induces a forward, or'reverse flow of air around. the trailing edge of the wing. In normal flighttthismeverseflow ex- 1 '2 tends forward but avery slight distance, but ,asthefangle of attack is increasedandthe speed diminished,,this reverse flow moves the wing, the boundary layer.

forward on thickens and finally reduces the'liftingpower to a point where the normal flow is complete-v .ly broken "down" causingiwhat is usually termed burbling in the boundary layerwith resultant loss of lift'and complete loss of con propeller, 4 the tail, 5 the horizontal'stabilizl er, 6 elevators, 7 the rudder, 8 .thefifin or ver: 5

trol and the difliculties attendingthereto. It to avoid this difficulty by opening passages from the bottom of the wing to the top of the wing to create an aux;

iliary air flow to neutralize, or prevent this I increase in reverse movement andthickening 4 of the boundary layer and to restore the normal air flow over the top surface and to thus avoid the burbling action and the loss of lift While such passages will accomplish this re-&

sult they produce an abnormal drag in nor-t '45 mal flight. To avoid this, it has been proposed to make the wing in sections and open the sectionsto produce the passages and to close thesections in normal flight. This leads to many complications in structure and reducesvery materially the wing strength, parutilized when eonfinedto asingle slot adjacent to the,

leading edge ofthie wing. Thepresentinveritionis designed tocorrectxin an efficient man? nerthedifiiculty as to air flow 'with'the angle: 5

of, attackrabove the critical of the normal 6 I and details of the invention will appear, from c the'specificationfand'claims; 1f f I I; I ,pe v A preferred embod ment of theiinvent n' U is illustrated-inthe accompanying drawing as v follows i Fig; '1 is a cross sec-tionofza wing on the a: Fig. 2 similarviewwith the position.

closure plates, a a

Fig.4 a plan view ofjthe' plane. i r

Fig. '5 a detail of thecontrolconnections. 1 1 marks the fuselage, 2 the engine, 3 the frame structure.

The leading edge 15Jis'preferably'movably mounted on the wing structure by means of links 16 pivotally mounted at 17 on the frame, p

theupper ends of the links being connected= at 18 to a projection 19 on the movablelead- 5 j ing edge. As this edge swings forward it p opens a slot'20 which slotpermitsof "aimove ment of, air through the slot so'asto obviate" if the difliculties encountered when the angled"? he front and remorse, f

present invention proaperspectiveviewof 1 i H IM O This; invention permitsof theluse of a conventional] 51.,

of attack is above the critical. The action of such a "slot at the leading edge iswell known and does, to some extent, correct the difficulty encountered when the angle of at- 'stricted toward the top and are inclined upwardly towardthe rear so that the air passing v through them rapidly increases in velocity as it passes through the slot and emerges at the upper side of the plane at high velocity, The eifect of this is to reduce the pressure at the upperjsurface of the plane to prevent the 7 forward movement of the return flow around in present construction.- Al Closure plates 22:

the-trailing edge of the planeand to avoid the creation of the burbling action-as the angle of attack rises above the critical point of the normal airfo'il. Thisactiontends to" stabilize the aeroplane-and. permits thec'ontinuancef of lifting force at speeds-Well be low thosefof themnormal airfoil and while thQIG'lS a rearward movement of the center of pressure on the wingthis rearward motioninthe absence of theburbling action above thewing sreallya stabilizer rather than one creating the lossof control incident tostalling are pivotallv mounted at-23 on rods 23a along one-edge of the bottoms'of "the slots. The

' rods-23o are mounted, in the frame. These I normal flight.

closure plates' whenin closedposition, as

shown in vFig. 1, present a lower: surface similar to the lower surfaceof the normal plane and, :therefore, create I practically" no drag-in The upper ends of the slotsare' so restricted. and so' inclined as to present,

practicallyno drag in normal flight, particula'rly as they'lead into the boundary layer.

v Links 24 lead from the closure plates and are connected with links 25; The links 25 are pivotally mounted at 26 on'brackets 26a arranged in theframe; The links 2tand. 25

tending through the Wing are pivotally connected at-27a to controlrods I v v 27 extendingforward and aft of the w ng, the forward ends of thelinks 27 being pivotally connected at'28 to links 16. .Preferably there is one of the link systems including the links. 24, 25 and control rod 27 at each compression strut of the frame of the wing. The

closure plates. I'prefer, however to provide in, additionto such automatic control a-man-' ual control for this-purposes Bell cranks 29 are pivotally mounted on the frame at points 30, one for each of the control rods 27, with push and pull rods 31leading by connectionsito the cockpit. Arms 32.;of these leading edge will open" automatically and if of sufficient power will open and close the bell cranks are connected by links-33 with the 2 3131181950 thatas the push and pull rods 31 are moved theleading edge and the closure plates are actuated wTh e 31 extend to both bell crank sides of theplane v and the push-and pull rods levers 29v are, so arranged thatall j the slots are opened, orelo'sed;simultaneously.

Itwill be noted-thatthe links-.2 i'and-25 are brought into alineme-ntas the plates" 22 are closed-,thus' securely lockinglthein in closed position Twithout furtherstrain-on the rod 27. VhatIclaim'asIneWis 5 1.v An aeroplane wing-having aymovable" leading edge, and provided with 1 slots eX-"- from top to bot-v tomlwithj the p'ortion's..to theqfro'n'tand rear of the slot relatively rigid slots; and-a connection. between, the closure and themov'able leading "edge opening -s-aid slots as'the leading'edge is moved forward on the swing.

; closures for said 2. An aeroplane wing.having a: rnovable leading edge and having a slot extending through the; wingfrom'top to bottom with the portionsto the front Jandrear-of the slot t relatively rigid; a closure for said slot; and

a connection between-the closure and the m'ovable leading edge open-mg said slotas the leading edge is moved forward ontherwingz r ROGER GBISWOLD

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