USRE24099E - maxwell - Google Patents

Description

Dec. 6, 1955 F. R. MAXWELL AIRPLANE WING WITH VARIABLE NOSE SLOT Re. A24,099

5 Sheets-Sheet 1 Original Filed Feb. l1, 1942 F7 Il Dec. 6, 1955 F. R. MAXWELL AIRPLANE WING wrm VARIABLE Nos sLoT 5 Sheets-Sheet 2 original Filed reb.v 11, 1942 5 Sheds-Sheet 3 Dec. 6, 1955 F. R. MAXWELL AIRPLANE WING WITH VARIABLE NOSE SLOT Original Filed Feb. l1, 1942 Dec. 6, 1955 F. R. MAXWELL AIRPLANE WING WITH VARIABLE NOSE SLOT Original Filed Feb. l1, 1942 5 Sheets-Sheet 4 amati! Y Dec. 6, 1955 F. R. MAXWELL AIRPLAN WING WITH VARIABLE NOSE SLOT 5 Sheets-Sheet 5 Original Filed Feb. il, 1942 www4 United States Patent Ol AIRPLANE WING WITH VARIABLE NOSE SLOT Frank R. Maxwell, Washington, D. C.

Original No. 2,381,678, dated August 7, 1945, Serial No. 430,317, February l1, 1942. Application for reissue July 27, 1955, Serial No. 524,836

s Claims. (c1. 244-42) Matter enclosed in heavy brackets [l appears in the original patent but forms no part of this reissue l cation; matter printed in italics indicates the additions made by reissue.

. extending adjacent the leading edge from the root of the wing to adjacent the tip, in order to increase the lift on the wing and enable lower flying speeds and consequently lower landing speed.

As will be appreciated, the purpose of the wing slot is to increase the angle of incidence at which the wing stalls and thereby increase the maximum lift of the wing. However, in many wings the angle at which the various sections of the wing stall varies from root to tip of the wing. Thus, for example, in the case of a tapered wing the section adjacent to the top -usually stalls before the section adjacent to the root, and vice versa in the case of a straight wing.

Desirably, in order to obtain the maximum lift, a wing slot will be so designed that all portions of the wing will stall at approximately the same angle of incidence and that angle will be the largest attainable. Further, it is essential that that section of the wingvnear the tip, in the way of the aileron, or other means of lateral control, should not stall before the center section and, preferably. a little after the center section, so that lateral control may be maintained at and adjacent to the point of stall of the entire wing.

As will be apparent, the slots as heretofore used and of the continuous type are not eective to adjust the angle of incidence of a wing to the maximum obtainable amount and, atr the same time, retain adequate lateral control, when the wing is of a type such that the natural angle of stall without slots varies in different sections throughout the lateral extension of the wing.

Now in accordance with this invention, I provide a wing having means for forming a slot which is effective to adjust the angle of incidence of a wing to the maximum amount with retention of lateral control up to the stall. The novel slot according to this invention comprises a plurality of sections, adjacent the leading edge and extending from the root to adjacent the tip of the wing.

More particularly, the severalsections of the slot mayv be of different contour, of different length and of different n width, or tapered, al1 respectively with relation to the portions of the wing and the chord thereof with which they are respectively related and the aerodynamic conditions obtaining with respect thereto. Further, the several sections may be at different angles relative to the chord of the wing. Y

Further, `more particularly, means may be provided Re. 24,099 Reiaaued Dec. 6, 1955 ,ICC

opened different amounts to the end that the angle of maximum lift may be varied throughout the extension of the wing with reference to the aerodynamic effects obtaining in different portions of the wing when'the effect of the slot is utilized.

Having now indicated in a general way the nature and purpose of this invention, I will proceed to a detailed description of a preferred embodiment with reference to the accompanying drawings, in which:

Figure 1 is a plan view, partly broken away, of a wing having a rear llap and provided with means for forming a slot comprising a plurality of sections according to this invention.

Figure 2 is a sectional view on line 2-2, Figure 1, looking in the direction of the arrows.

Figure 3 is a sectional view on line 3.3, Figure l, looking in the direction of the arrows.

Figure 4 is a sectional view on line 44, Figure l, looking in the direction of the arrows.

Figure 5 is a plan view, partly broken away, of a wing embodyinga modification of this invention as shown in Figure 1.

Figure 6 is a fragmentary sectional view showing means for forming one of the slot sections in closed position with. means for opening and closing the slot.4

Figure 7 is a sectional View showing the-subject of Figvure 6 with the slot open.

Figure 8 is a fragmental sectional view of a flap in inoperative position and means for its operation.

Figures 9 and 10 are diagrammatic views exemplifying the cooperative movement of slot forming means and the flap. f

Figures 11 and 12 are fragmentary sectional views showing modification of the means for opening and closing the slot, the slot being shown closed in Figure 1l and open in Figure 12.

Figure 13 is a sectional fragmentary view of a rear flap with modified means for manipulating it. f

Figures 14-16 are fragmentary sectional views of other modified means for opening and closing the slot, the slot being shown closed in Figure 14 and open in Figures 15 and 16. v

f Referring to the drawings, the fuselage of any airplane is indicated at 1, while 2 indicates a wing. The-wing is provided adjacent its leading edge with a slot generally indicated at 3, and formed in a plurality of sections 3A, 3Brand 3C. The several slot sections are formed by means of upper slot covers 28 and lower slot covers 30 of any-usual construction and mounting indicated in Figures 6 and 7. The wing is provided with a trailing edge flap 4 and an aileron 5.. v f

As shown in Figure l. the several sections forming the slot may respectively .vary in width with relation to the chord of the wing, it being noted that the several sections as shown are of uniform width, but that, however, the chord of the wing varies in the extension of the wing from root to tip. However, as shown in Figure 5, a constant relation between slot widthand wing chord may be maintained by, as shown, tapering the slot with the taper of the wing. Again, as shown Vin Figure l, the slot sections may varyinlength, it beingV noted that the middle section is shorter than the end sections. Y,

With reference to Figures 2-4, it will be noted that the f contour of the slot in cross section is varied in the several whereby the several sections forming slot may be f' sections, the particular contour for the several sections As has been indicated,the slot, comprising the-sections 3A, sa and sc, is adapted m be opened in cooperation with operation of thetraiiing edge flap 4it being noted thattheseveralseetionsofthegslotmaybeopenedan 3 equal amount or respectively in dilerent amount, and in cooperation with operation of the trailing edge flap.

To such end an arm 8 (Figure 8) is attached at one end to the trailing edge ilap 4, for example, to the hinge pintle 7 of the llap, which in usual manner is hinged to the wing and in inoperative position fits into a recess 6 in the underside of the wing, and at its other end to the rod 9, by a pivot 10. The rod 9 extends longitudinally of the chord of the wing and is connected to any suitable form of mechanism, as a screw and nut mechanism, indicated at 9 (Figure l) with connection to operating means located conveniently to the pilot and adapted to exert a push or pull on the rod for lowering and raising the ap into and out of operative position. As will be apparent from an inspection of Figure l a plurality of arms and rods similar to arm'8 and rod 9 will be provided ,for the operation of the ap.

A segment l1, having a plurality of openings 12 adjacent to its periphery, is attached, for example, to the pintle 7 or otherwise to work with arm 8. The segment ll is connected by an adjustable link 18 to a lever 13, pivotally mounted, as at 15, on a bracket 16 secured to an element of the internal structure of the wing. One arm of the lever 13 is connected to a rod 19, as at 20, while its other arm is extended and provided with a plurality of openings 17. It will be noted from an inspection of Figure 8 that the link 18 may be connected to the segment l1 through any one of the apertures 12 and to the lever 13 through any one of the apertures 17.

The arm 19 extends longitudinally of the chord of the wing and is pivotally connected, as at 22 (Figures 6-7) to an arm of a bell crank lever 21, which in turn is pivotally mounted, as at 23, on an element of the internal structure of the wing, at a point adjacent to the slot 3. To another arm of the lever 21 is attached, as at 25, a link 24 which in turn is connected to an adjustable link or turnbuckle 26, which in its turn is pivotally connected, as at 27, to the underside of the upper slot cover 28. The angularity of the link 24 may be adjusted with respect to the lever 2l by means of a threaded rod 42 pivotally connected at one end, as at 43, to the link 24, and extending through a nut 45 pivotally mounted, as at 44, on lever 21.

The third arm of the lever 2l is connected to a link 38, through a slot and pin connection 39, 40, Figures 6-7, the link 38 being in turn connected, as at 37, to a lever 33 pivotally mounted, as at 35, on the upper slot cover 28. The lever 33 is in turn connected, as at 34, to an adjustable link 31 pivotally mounted, as at 32, on the lower slot cover 30. A spring 41 is connected to the link 38 and to an element of the internal structure of the wing.

As will be appreciated from an inspection of Figures l and 5, a plurality of rods similar to rod 19 and connections therefrom to the upper and lower slot covers 28 and 30, as through levers similar to lever 21, are provided for the covers forming the sections of the slot, as, for example, sections 3A and 3B, opposite to the rear ilap.

For operation of the covers 28 and 30 of the section 3C of the slot beyond the outer end of the rear ap, as shown in Figure l, the outer rod 19 is connected to a rod 47 extending longitudinally of the wing by means of a lever 48 mounted in the wing and the rod 47 is connected to a pair of levers 2l through the medium of levers 46 mounted in the wing and short arms 19'.

For the operation of the covers 28 and 30 for the opening of the sections of the slot 3 in cooperation with operation of the rear ap 4, the adjustable links 18 are connected to the segments 1l and levers 13 for desired relative movement of the flap and slot covers. Thus, by reference to Figure 9, it will be noted that if the links are connected through the medium of the opening I in both the segment and lever, the lever 13 will not move toopentheslotuntilthe segmentltasturnedsubstantially with consequent downward movement of the ap. Again (Fig. 10), if the connection between opening I in the lever and opening IV in the segment is made, the

lever willbe moved when the segment is moved with consequent opening of the slot when the ap starts to move downward. It follows that various openings of the slot as a whole or of its various sections respectively with respect to downward movement of the ilap may be obtained by variously connecting the links 18 to the segments 11 and levers 13, as a whole or as they control the openings of the several slot covers respectively.

Again, the degree of opening of the slot covers, respectively, is adjustable through adjustment of the angularity of the links 24 with respect to the bell crank levers 21, through the medium of the threaded rods 42 and nuts 45.

The ap and slot cover operating mechanism having been adjusted for the desired timed opening of the sec' tions of the slot with respect to the operation of the ap and for the degree of opening of the several sections of the slot, respectively, it is believed that the operation of the mechanism will be obvious, it being noted that, on operation by the pilot of the screw and nut 9' for lowering the flap 4 to an operative position, the segments l1 will be turned, causing the levers 13 to be rocked and to push the rods 19 forward. 'l'he forward movement of the rods 19 will cause the levers 21 to be rocked with the result that the upper and lower slot covers will be raised to open the slot sections 3A and 3B. The slot section 3C will be opened at the same time through the medium of lever 48, rod 47, levers 46 and rods 19'.

It will be noted that the connections between levers 2l and the lower slot cover and, more particularly, the slot and pin connection between links 38 and levers 21, together with the action of springs 41 on links 38, will permit the lower slot covers 30 to be fully opened in the initial opening movement of the upper slot covers 28, i. e., before the slots are efectively opened, and to permit them to remain in fully open position during the range of movement of the upper covers 28 for elective opening of the slot sections.

As has been indicated, the several slot sections may be opened in various timed relation to operation of the rear tlap and respectively to dilerent extent by adjustment of the links 18 withrespect to the segments 11 and levers 13 and by adjustment of the angular relationship of the links 24 with respect to the levers 21 through the medium of threaded rods 42 and nuts 45.

Referring now to Figures 11 and l2, in which are shown modified means for opening and closing the slot, the push rod 19 is pivotally connected to a three armed lever 5l, pivotally mounted as at 52 within the wing structure adjacent to the slot 3, a longitudinally adjustable link 54 is pivotally connected to another arm of the lever 5l as at 53 and to the upper slot cover 55 as at 56.

The lower slot cover 59 is provided with an arm 61, to which is pivotally connected a sleeve 63, within `which is a spring 64 and within which extends a rod 65 pivotally connected to the lever 51 as at 66. The rod 65 is engaged with the sleeve 63 through the medium of a slot and pin connection 67, 68. For adjustment of the slot openingin the modification of Figures ll and 12, it will be noted that the lever 5l is provided with a plurality of apertures 70 enabling the link 54 to be variously positioned in its connection with the lever 51. Thus, by connecting the adjustable link 54 with the lever 51 through dierent apertures 70, the full opening of the upper slot cover can be varied, as shown in full and dot dash lines Figure l2.

Further, it will be noted from an inspection of Figure l1 that when the slot cover is closed the pivot points 52, 53 and 56 are in line and hence forces acting to open s x theupperslotcoverarenottransmittedtootherconu'ol surfaces.

WithreferencetoFigure l3,itwillbenotedthatthe rearap4isoperatedthroughthemediumofanarm 7l mounted on the pintle 7 and pivotally connected to the pushrod l9at72indistinctionfrumthearrangement shown in Figure 8.

Referring now to Figures 14-16, a lever 8l is pivotally mounted within the wing structure as at 82. The push rod19ispivotallyconnectedtoanarmoftheleverasat 80. An adjustable link 84 is pivotally connected to the upper slot cover, as at 86, and to the lever 8l by means of `a pin 83 passed through one or another of the apertures 83'. The apertures 83', it will be noted, extend in a line radially from the pivotal mounting 82 of the lever. The link 84 is bent to avoid interference with the pivot 82. The lower slot cover 89 is provided with an arm 91, to which is pivotally connected, as at 109, a sleeve 92 within which is a spring 93 and into which extends a rod 94 pivotally connected to lever 8l, as at 95. 'lhe sleeve 92 and the rod 94 are connected through the medium of slot and pin connection 96, 97.

By reference to Figure 14, in which the slot covers areshowntobeinclosedposition,itwillbenotedthat with the slot'covers closed the pivots 83, 82, 86 are substantially in line, as are also the pivots 82, 95 and 190.

The in line relationship of the pivotal connections indicated will, as will be appreciated, prevent the forces acting upon the upper slot cover and upon the lower slot cover from operating to open these covers, and it will also prevent transmission of auch forces to other portions of the mechanism.

As shown in Figure 1 6, various openings of the upper i slot cover may be obtained by use of one or another of the openings 83' for connection of the adjustable link 85 to the lever 81. As will be appreciated, the lower slot cover, due to the construction of the member connecting the arm 91 with the lever 8l, will be fully opened when the upper slot cover is opened, irrespective of the adjustment for amount of opening of the upper slot cover.

The several slot sections may be given the same or diferent contours and the several sections may vary in width proportionally to the chords of the wing or be conetant with respect thereto.

As will be obvious from the foregoing description, the wing 2 provides a main airfoil section while the upper slot covers 28 form auxiliary airfoil sections arranged relative to the leading edge of the main section 2 to form the slots 3A, 3B, 3C. The prole sections of the covers, or auxiliary airfoil sections 28, respectively are of diterent contour, it being noted from an inspection of Figures 2,3and4thattheanglesofincidenceoftheaeveral auxiliary airfoil sections are ditferent, and that more apecically the angles of incidence of the sections respectivelydiminishinadirectiontromtheroottowardthe tip of the main section, i. e., the angles of incidence of the auxiliary airfcilsections forming the slot 3B (Fig. 3) is less than that of the auxiliary airfoil section forming the slot 3A (Fig. 2) and that of the auxiliary airfoil seo tion forming the slot 3C (Fig. 4) is less than that of the auxiliary airfoil section forming the slot 3B (Fig. 3). As will also be obvious, if a single auxiliary airfoil section, inplace of a plurality of auxiliary airfoil sections, isprovidedtoformasingleslogprotlesectionsofthe auxiliary airfoil section taken at diterent points in its longitudinal extension will be of diferent contour.

It will now be appreciated that by virtue of this invention a slot extending eectvely from the root of a wing to adjacent its tip, is provided which aerodyuamically will exactly complement the various aerodynamic conditions obtaininginthevariouspartsofthewinginitslongitudinalextensionsothatmaximumlifteectwillbe obtained from the slot without negative eect upon lateral stability.

Itwillbeappreciatedthatitisnotintendedthatthis 6 invention shall be limited to the details of construction described herein, it being obvious that various structural modifications may be made without departing froml the scope of the claims appended hereto.

What I claim and desire to protect by Letters Patent is:

l. [An airfoil] An airplane wing having a root and a tip and comprising a main airfoil section and an auxiliary airfoil arranged relative to the leading edge ofthe main section to form a slot, said auxiliary airfoil being characterized by the fact that the angle of incidence of the profile sections thereof taken at a plurality of dierent points in its longitudinal extension diminishes progressively in a direction from the root toward the tip of the main airfoil section.

2. [An airfoil] An airplane wing having a root and a tip and comprising a main airfoil section and an auxiliary airfoil movable relative to the leading edge of the main section and adapted to be positioned to form a slot, said auxiliary airfoil being characterized by the fact that prolle sections thereof taken at a plurality of dilierent points in its longitudinal extension are of Adierent contour, the ratio of the width of the said auxiliary airfoil to the' chord of the wing increasing progressively from the root toward l the tip.

3. [An airfoil] An airplane wing having a root and a from the root toward the tip.

4. [An airfoil] An airplane wing having a root and a tip and comprising a main airfoil section and an auxiliary airfoil movable relative to the leading edge of the main section and adapted to be positioned to form a slot, said auxiliary airfoil being characterized by the fact that the angles of incidence of proile sections thereof taken at a plurality of dierent points in its longitudinal extension diminish progressively in a direction from the root toward the tip of the main airfoil section.

5. [An airfoil] An airplane wing having a root and a tip and comprising a main airfoil section and a plurality of auxiliary airfoils movable relative to the leading edge of the main section and adapted to be positioned to form a plurality of slots extending successively in a direction from the root to the tip of the main airfoil section, said auxiliary airfoil sections being characterized by the fact that their protle sections respectively are of dierent contour, the ratio of the width of the said auxiliary air foils to the chord of the wing increasing progressively from the root toward the tip.

6. [An airfoil] An airplane wing having a root and a tip and comprising a main airfoil section and a plurality of auxiliary airfoils movable relative to the leading edge of the main section and adapted 'to be positioned to form a plurality of slots extending successively in a direction from the root to the tip of the `main airfoil section, said auxiliary airfoil sections being characterized by the fact that their profile sections respectively are of dierent length, the ratio of the width of the said auxiliary airfoil: to the chord of the wing increasing progressively from the root toward the tip.

7. [An airfoil] An airplane wing having a root and a tip and comprising a main airfoil section and a plurality of auxiliary airfoils movable relative to the leading edge of the main section and adapted to be positioned to form slots, said auxiliary airfoils being characterized by the4 fact that prolle sections thereof taken at a plurality of dierent points in the longitudinal extensions thereof are of dilierent contour, the angles of incidence of said aux illary airfoils diminishing from the root toward the tip,

andlfurther characterized by the fact that means are pro- Rdereleel Cited in the le of this patent vided for moving the nuriliary airfols respectively to n or the original patent different extent relative t0 the leading edge 0f the mnin I l UNITED STATES PATENTS airfoil section. f

s, [An airfoil] An airplane wing having n root und a 5 1'472199 Thomson oct' 30 1923 rip and comprising a main airfol section and a plurality 1'862'902 McDonnell June 14 1932 0f auxiliary airfoils movable relativeto the leading edge "880367 Maxwell Oct 4' 1932 of the main section and adapted to be positioned to form 2'041'688 Bamba May 26' 1936 a plurality of slots extending successively in a diremo!! 2070'705 Bamba Fb' 16' 1937 from me root o me tip of the main aixfcil section and 10 f ,)eisl' 32 means for moving the auxiliary axrforls respectively rela 2.298,2 cm1 et al. oct. 13 1942 ent angles of incidence relative to the main airfoil section, 2'324303 Johnson July 13' 1943 the saidl angles of incidence diminishing progressively 15 FOREIGN PATENTS f'o'" he '0' award he "P- 311,442 Great Britain Apr. 2s. 1932 517,422 Great Britain Ian. 30, 1940

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