US3063375A - Folding fin - Google Patents

Description

Nov. 13, 1962 w. w. HAWLEY EI'AL 3,

FOLDING FIN Filed May 19, 1960 3 Sheets-Sheet 1 WILBUR W. HAWLEY DAVID J. HAYKIN,Jr.

ATTORNEYS Nov. 13, 1962 w. w. HAWLEY EIAL 3,063,375

VFOLDING FIN Filed May 19, 1960 3 Sheets-Sheet 2 WILBUR W. HAWLEY DAVID J. HAYKIN, Jr.

\ ATTORNEYS Nov. 13, 1962 w. w. HAWLEY ETAL 3,0 3,3 5

FOLDING FIN Filed May 19, 1960 3 Sheets-Sheet 3 WILBUR W. HAWLEY DAVID J HAYKIN, Jr

INVENTORS ATTORNEY United States Patent ()1 States of America as represented by the Secretary of the Navy Filed May 19, 1960, Ser. No. 30,393 3 Claims. (Cl. 102--50) The present invention relates to folding fins for booster rockets and the like. More particularly, it relates to a fin folding arrangement wherein the fin axis or span extends parallel to the airframe longitudinal axis in a collapsed condition and is erected principally by a rotary movement.

Prior folding fins comprise either a telescoping arrangement or a single hinge joint which may be located at the fin root or at some point along the fin span. Telescoping fins are generally unsatisfactory if subjected to extremely high aerodynamic loads such as are encountered in transonic and supersonic flight. Hinged fins do not greatly reduce the stowage space if the fin span exceeds the diameter of the missile. The present invention, however, is capable of reducing the required stowage area practically to the area of a square circumscribing the missile cross section even though the fin span may be'considerably greater than the length of one side of the circumscribing square.

Accordingly, it is an object of the present invention to provide a missile structure having collapsible wings or fins.

It is a further object to provide a missile structure in which the fins are collapsed at all times during stowing or handling and are erected only upon launching the missile.

Another object of the invention is to provide a folded fin missile structure in which a large part of the force required to erect the fin is supplied by setback upon launching the missile.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 is a perspective view of the present invention showing its application to the booster rocket of a missilecombination, the fins being shown in fully folded positions;

FIG. 2 is a perspective view of the fin mounting portion of the booster rocket of FIG. 1 showing the fins shortly after initiation of the erecting operation;

FIG. 3 is a view similar to FIG. 2 except that the fins appear in medial positions;

FIG. 4 is similar to FIG. 3 except that the fins have progressed very nearly to their final extended positions;

FIG. 5 is a rear view of the booster with the fins shown in the positions of FIG. 4;

FIG. 6 is a perspective of the rear portion of the booster rocket showing the fins in fully erect positions;

FIG. 7 is a plan view of the rear portion of the booster showing certain elements of the fin erecting mechanism in phantom; and

FIG. 8 is a partial sectional view taken along the line 8--8 of FIG. 7.

FIG. 1 illustrates the invention as applied to a jettisonable booster rocket 10 similar to those commonly employed in launching a large variety of guided missiles. The rocket 10 is supported on a launcher rail 12 by means of shoes 13 and 13'. A missile 14 is detachably secured to the forward end of rocket 10. The missile 14 is designed for supersonic operation and hence requires a wing of only a small span to deliver the necessary control moments and lift. The booster rocket however is needed only during the subsonic and transonic portions of the missiles 3,063,375 Patented Nov.'13., 1962 ice flight. Once the missile has reached a supersonic speed the booter is jettisoned, reducing both the drag and the weight which would otherwise need to be transported by the missile. Because of the greater span, the booster fins create a more severestorage and handling problem than do the missile fins. For this reason the invention is illustrated and described as being applied only to the booster although obviously it may be applied to the missile fins if desired.

The four booster fins 15 are folded forwardly with their span axis paralleling the booster longitudinal axis and with one surface of'the fin tangent to the body of the booster 1d. The root edge 16 of each fin 15 faces aft. The launching shoe 13' is secured to the root edge of the upper fin 15 and for aerodynamic balance a similar shoe may be secured to the lower fin. A skewed actuating rod 18 extends from the interior of the rear portion of booster 10 to the fin root edge 16, to which it is rigidly secured, as by welding. The rod 18 serves both to erect the fin and to secure it either in a folded or an erected position. A simple rotary motion of the rod 18 causes the attached fin to rotate so that the forward tip 19 of the fin moves both outwardly and towards the rear while the fin root 16 rotates from a position transverse to the longitudinal axis of the booster to a position paralleling the booster longitudinal axis.

FIGS. 2, 3 and 4 illustrate the effect of rotating rod 13. In FIG. 2, at the commencement of the erection operation, the fin tip 19 is displaced aft and outwardly from the position shown in FIG. 1. FIG. 3 shows the position of the fins after motion has proceeded to a more advanced stage. Further rotation of actuating rod 13, from the position of FIG. 3, through a total of from the position of FIG. 1, produces the condition shown in FIGS. 4 and 5. The fins 15 are fully erect, but are off-set from the missile center line with the root 16 slightly elevated above the booster body. The off-set is removed, and the fins 15 are lowered into proper alignment as shown in FIG. 6, simply by retracting actuating rod 18.

The fin actuating mechanism is shown in FIGS. 7 and 8. It should be understood that a large contribution to the actuating force is supplied by the booster set-back forces, since acceleration supplied by the booster thrust is commonly in the neighborhood of 15 g. Therefore, the primary function of the actuating mechanism is to move the fins into a slightly unbalanced condition whereafter the inertia of the fins will account for the major portion of the force needed to complete the operation.

The rear portion of the booster includes a nozzle 21, best seen in FIG. 7, shrouded by the booster skin 22. The actuating mechanism is enclosed within the space provided by the constriction of the nozzle throat and includes .four actuating cylinders 23, only one of which is shown. Cylinder 23 is pivotally secured to a boss 24 cast on the outer surface of nozzle 21. The hydraulic pressure line connections to cylinder 23 are not shown but it will be understood that a suitable source of hydraulic power is made available to cylinder 2-3. The piston rod 25 of cylinder 23 is pivotally connected to a bell crank 26. The lower end of rod 18 is splined, as seen at 27 in FIG. 8, and crank 26 is provided with teeth so that rod 18 is constrained to rotate with crank 26 but is free to move axially. Rod 18 passes through a guide bushing 28 secured internally of the booster. The bushing 28 is provided with a slot 31 through which extends a guide pin 32 secured to rod 18. A compression spring 33 is fitted over the end of rod 18 and held in place by a cap 34 fixed to the end of rod 18. Spring 33 bears against crank 26 and imparts a thrust to rod 18 urging the rod to retract into the booster. Initially, rod 18 is prevented from retraction by pin 32 riding the portion of slot 31 which extends partially about the circumference of bushing 28. When the piston rod of cylinder 23 has been extended sufliciently to drive crank 26 through 120 and hence to rotate rod 18 an equal amount, pin 3-2 will have travelled to the portion of slot 31 extending along the axis of bushing 28. The thrust of spring 33, then unresisted, causes rod 18 to withdraw into the booster. The splined connection of crank 26 to rod 18 also permits this desired motion to occur without interference.

FIGS. 7 and 8 illustrate the relative positions of the elements of the actuating mechanism when the fins are in the folded condition of FIG. 1. The fins are retained in this folded position so long as the piston rod 25 does not move. When it is desired to erect the fins pressurized fluid is brought to act upon the piston rod, causing it to move from its initial position. During the erection operation shown progressively in FIGS. 2, 3 and 4, the piston rod 25 extends, crank 26 rotates and pin 32 travels the length of the circumferential portion of slot 31. At this stage, the fins are in the position of FIGS. 4 and 5. Finally, pin 32, having arrived at the axially extending portion of slot 31, allows spring 33 to retract rod 18 and move the fins from the position of FIGS. 4 and to the position of FIG. 6. A recessed portion 35 of the booster receives the launching shoe 13' as the fin is drawn into its final erect position and thus fairs the booster surface for the reduction of drag.

As best seen in FIG. 7, a portion 36 of the root of fin is cut away so that the leading edge of the fin will not strike the booster body when the fins are approximately in the position of FIG. 3. An island 41, best seen in FIGS. 3 and 4 and shaped similarly to the cut-away portion 36, is built up from the booster body to provide a smooth fairing of the fin into the booster body. The island structures 41 may be provided with a suitable mechanism for latching the erected fins in place, although the restraint provided by the actuating mechanism is sufiicient for many applications.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A collapsible wing arrangement for aerial vehicles, including a vehicle body of generally cylindrical form, a planiform airfoil having a root edge and a tip edge opposite said root edge, said airfoil being normally carried edgewise to the airstream with said root edge secured to said body, a shaft rigidly secured to said root edge oblique to the plane of said airfoil and extending into said vehicle body oblique to a plane perpendicular to the longitudinal axis thereof, said shaft being mounted within said body for rotational and axial shifting movement and being so disposed relative to said two planes that rotation thereof will move said airfoil from a collapsed position, wherein the plane of said airfoil is tangent to the vehicle body with said tip ahead of said root edge along the line of travel of the vehicle, to a position wherein the airfoil is edgewise to the airstream with the root edge thereof spaced from said body and with the plane thereof laterally offset from and parallel to a plane including the longitudinal axis of said body, means for rotating said shaft, and means for axially retracting said shaft into said body to thereby shift the plane of said airfoil into said last mentioned plane.

2. A collapsible wing arrangement as recited in claim 1, wherein said means for rotating said shaft includes a bell crank connected to said shaft and a hydraulic piston connected between said bell crank and said vehicle body, said bell crank being so connected with said shaft that the latter is constrained to rotate with said crank but is free to shift axially, and wherein said last mentioned means includes a cap afiixed to the free end of said shaft and a resilient means compressed between said cap and said bell crank.

3. A folded fin configuration for booster rockets and the like, comprising a rocket body, a stabilizing airfoil generally planiform and normally carried edgewise to the airstream with its root end secured to said body, a rotatable shaft extending from the interior of said body askew to a plane perpendicular to the longitudinal axis thereof and oblique to the plane of said airfoil, said shaft being rigidly secured to the root end of said airfoil for rotating said airfoil from a first position, wherein said airfoil is carried tangent to said body and extends longitudinally therewith, to a second position, wherein said airfoil is presented edgewise to the direction of the airstream with the root end thereof adjacent said body, means for rotating said shaft, and means for retracting said shaft to translate the position of said #airfoil into a plane containing the longitudinal axis of said body.

References Cited in the file of this patent UNITED STATES PATENTS 1,166,879 Alard Jan. 4, 1916 2,427,217 Lebherz et al. Sept. 9, 1947 2,940,688 Bland June 14, 1960

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