Flying Body Having Extensible Fins

Abstract

A flying body, in particular a projectile of a type which is adapted to be jected from a tube includes a tubular outer casing and a plurality of tail fins conforming to the configuration of the casing and arranged at spaced circumferential locations therearound which are held by extension means under tension when the fins are retracted in position within the tube. When the projectile is directed out of the tube the extension means move in a direction to cause outward movement of the tail fins into an operative position.

Description

SUMMARY OF THE INVENTION

This invention relates in general to the construction of flying bodies and in particular to a new and useful projectile or missile adapted to be ejected from a tube or receptacle and which includes fins, particularly tail fins which are moved by extension means outwardly from the body of the projectile automatically when the projectile is expelled from the tube.

Extensible fins for flying bodies such as projectiles or missiles are known, for example, tail fins are known which may be pivoted about supporting axes to extend substantially radially to the fin carrier in the operative state and to extend in the folded state coaxially to the longitudinal axis of the associated projectile. In such operations, the pivot shafts are arranged at the rear in respect to the direction of flight of the projectile. Such an arrangement and design of the tail fins requires a relatively large overall length so that it is disadvantageous for small caliber projectiles. The turning of the tail fins about a fixed shaft also has the disadvantage that due to the small lever arm available between the fulcrum and the point of action of the force, rather great forces may be expended for the swing out. This leads to a relatively large and correspondingly heavy compression spring for effecting this movement. Such heavy compression springs can not be used in very small caliber projectiles. In addition the aerodynamic action of the oriented tail fins is unfavorable since a torque is produced.

In accordance with the invention there is provided a projectile or missile construction which includes one or more tail fins or similar fin elements which are formed to the configuration of the outer casing of the projectile so that they may overlie this casing in the retracted position in order to permit them to be positioned within a firing or storage tube. The construction includes a simple means for causing the automatic extension of the fins to move the fin elements in a direction away from the associated casing into an operative position at which they are extended outwardly from the casing. This automatic extension takes place after the projectile is directed out of the associated firing tube. The extension equipment avoids the disadvantages of the known tail fins or tail units and it is accommodated within a very small area, permitting favorable space utilization within the projectile which is particularly useful in the construction of small caliber projectiles. The construction is attained without reducing the aerodynamic effective surface and the fins may be transferred to their operative position with a simple operating mechanism.

For this purpose the tail fins are connected by radially extending webs which are carried on a ring member which may be moved axially in respect to the associated projectile or missile. The fins are arranged so that they can be extended in a translatory movement perpendicular to the air flow direction. The webs connecting the fins are mounted so that they are moved in a direction counter to the flight direction and outwardly to project the fins from the surface of the associated projectile. The connecting webs which are contained on a retaining member are guided on an inwardly inclined surface defined within the projectile casing. In the extended position, the associated web and the fins held thereby are held in a form-locking manner. Form-locking may be effected in the operative extended position, for example, by a wedging effect between the inclined surface guiding the webs and the associated web for each fin.

The arrangement of the tail fins so that they extend parallel to the axis of the projectile and so that they are held in this manner by associated projecting web elements permits the fins to be oriented for the first time to extend perpendicularly to the air flow direction. This has the advantage that only the mass of the individual tail fins has to be moved during the extension movement without having to overcome any flow resistances. In addition, the extension movement is enhanced by the air flow which presses against the facing fin cross section in the direction of the extension movement. The inertia also acts in the direction of the extension movement due to the displacement of the fins against the direction of flight. The aerodynamically effective lever length between the center of gravity of the projectile and the tail fins increases during the displacement. The tail fins bear, during their entire displacement movement for extension, on the inclined surface so that fluttering of the fins and the disturbance of the projectory of the projectile is prevented.

The inclined guiding surface for the web portions of the fins is advantageously defined as a shell of a truncated cone which is formed as an axially symmetrical hollow body which is secured to the bottom of the projectile through a cylindrical extension. The arrangement has the advantage that the interior of the truncated cone can be used for accommodating a jet propulsion unit if the tail fins are to be used in projectiles with their own propulsion system, i.e. in missiles. However, the hollow truncated cone interior can also receive a corresponding tip of another projectile, as is necessary, for example, when a number of projectiles or other flying bodies filling successively the cross section of a firing tube, have to be expelled from a single firing tube. For drop type missile bodies which are ejected from a receptacle which bursts automatically shortly after the drop, the arrangement of the tail fins of the invention is also suitable.

The extension mechanism for extending the tail fins advantageously comprises a compression coil spring, which holds the extended tail fins in an extended position, together with a force-locking notch-like engagement formed on a ring which contacts the web portion of the fins in the extended position. The tail fins are guided in a known manner by the movement of a web member in a slot formed in the projectile casing. The webs are guided by the inclined surface of the cone shell and in this manner a satisfactory flutter-free movement into the effective operating position is ensured.

The stability of each individual tail fin and its exact guidance is favorably increased by the fact that each tail fin has a thin base which is adapted to the configuration of the cone shell. Each tail fin includes an outer wing tip plate which conforms to the configuration of the outer casing of the projectile so that the tail unit is aerodynamically stable. The wing tip plates are advantageously made large enough to extend over a large circular arc surrounding the projectile to form an ample aerodynamically effective surface. In addition this provides ample surfaces of mutual contact between adjacent projectiles, in cases in which, as already mentioned, a number of projectiles have to be provided in one and the same cross sectional plane of a firing tube. The individual projectiles can be introduced into the associated tube without requiring the formation of the outer tip plates within narrow tolerances since the tail fins are held in their rest position by the associated part of the casing wall and as the case may be by adjacent projectiles.

A thrust ring which bears against all of the web portions of the tail fins is provided with guide ways which are adapted to the inner wall of the projectile casing and it is secured against rotation by projections which engage in slots in the casing.

Accordingly, it is an object of the invention to provide a flying body, in particular a projectile or missile, of a type which is adapted to be launched from a tube which includes a tubular casing having at least one tail fin with a plate portion of the configuration of the outer casing of the projectile and which overlies this casing when the fin is in a retracted position and the projectile is located within the firing tube, and wherein extension means are associated with the fin for automatically moving it outwardly to extend the tail plate away from the casing of the projectile after the projectile is expelled from the firing tube.

A further object of the invention is to provide a flying body, and in particular a projectile construction which includes a plurality of tail fin elements which are carried on webs which move in respective slots of a projectile casing and which are retained in their inoperative position by an approximately perpendicularly acting force, and including a member for guiding the tail fin elements outwardly from the casing upon release of the tail fin elements, and including a spring means for driving a thrust ring with the associated web means along the guiding member so as to move the tail fin elements radially outwardly from the surface of the associated projectile casing.

A further object of the invention is to provide a flying body having extensible tail fins which are simple in design, rugged in construction, and economical to manufacture.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view partly in section of the trailing portion of a projectile constructed in accordance with the invention; and

FIG. 2 shows a detail of FIG. 1 on a larger scale.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawing in particular, the invention embodied therein includes a projectile generally designated 50 having an extensible tail fin assembly generally designated 52 and which is of a type which is adapted to be accommodated in and launched from a firing tube 1.

In accordance with the invention, the tail fin assembly 52 includes a plurality of tip plates or end members 19 which are adapted to be extended after the projectile is launched out of the tube. In the embodiment shown in the drawing, the projectile 50 includes a total of four separate tip plates 19 of the configuration of the body or casing 2 of the projectile and which rest against this outer casing and are spaced around the periphery thereof when the projectile is located within the firing tube 1. A feature of the construction is that the projectile casing 2 accommodates supporting webs or guide plates 17 for each of these four separate fins 19 and the associated extension mechanism generally designed 54 for displacing the guide plates 17 rearwardly and outwardly to space the fins 19 outwardly from the casing after the projectile is ejected from the tube 1.

The projectile 50 includes at its rear or trailing portion a truncated cone 6 and an intermediate cylindrical piece 4. The intermediate piece 4 and the truncated cone 6 advantageously form a single part which is fixed by any suitable means to a base or bottom 3 of the projectile. The truncated cone 6 is designed as an axially symmetrical hollow body having a shell 7 which thickens toward the rear in the range of its base, (FIG. 2). In the shell 7 there is a circumferential recess 9 which serves as a retaining notch for a foot or guide member 18 of the web 17 in its extended operative position. The end of the cone shell 7 facing the projectile casing 2 is flattened to form a collar 10 so that the truncated cone 6 can be connected with the projectile casing 2, for example, by means of screws (not shown).

A compression spring 12 of conical form bears with one end on the projectile bottom 3 and with its opposite end on a recess 13 of a thrust ring 14. The thrust ring 14 bears against all of the tail fins, both in their position of rest or retracted position and in their operative or extended position.

The foot 18 of each of the webs 17 is in operative connection with the cone 6 and will move upwardly along the surface of the cone to the extended position shown at the lower portion of FIG. 1 and in FIG. 2 in which the tip plate 19 provides extended curved fin surfaces generally designated 16 in the retracted position and 16a in the extended position.

In the retracted position in which the projectile 50 is located within the firing tube 1, the tip plates 19 rest on the circumference of the casing 2 and in bearing contact therewith and are held in this position by the interior wall of the firing tube 1. The tip plates 19 are constructed so that they extend over a relatively large circular arc and so that there are only small intervals between the individual tip plates. The webs 17 of the tip plates 19 in the assembly shown are spaced approximately 90.degree. apart. This construction provides a maximum aerodynamic surface for a give cross section.

The web 17 has a trapezoidal form and is guided in a slot 20 defined in the projectile casing 2 and which extends longitudinally to the rear thereof. After the assembly of the tail fins the slots 20 are closed at the rear end by the collar 10 of the cone 6 which is secured to the casing 2.

The foot 18 of each fin extends laterally from both sides of the web 17 and it includes a projection 24 which engages on its side facing the cone with the corresponding recess 9 of the cone shell 7 in the extended position. The foot 18 is provided with a recess 22 along its edge which faces the thrust ring 14, which, in turn, is located to engage with a complementary edge 23 of the thrust ring 14 as indicated in FIG. 2. The thrust ring 14 is provided with four lugs 25 which are circularly curved to form guiding surfaces which bear against the inner wall of the projectile casing 2 and which extend perpendicularly with respect of the ring surface. These lugs are arranged at equally spaced locations. The parts of the ring between the lugs form the actual pressure surfaces for extending the tail fins. The thrust ring 14 engages the top of the end face 27 of the web 17 when the tail fins are in the retracted position (FIG. 1, top) while it slides downwards along the end face 17 of each tail fin during the extension movement until the recess 22 of the foot 18 engages the edge 23 of the ring 14.

The thrust ring 14 preferably includes two diametrically opposed projections 26 which are located between the lugs 25 as indicated in FIG. 2 and engage above the slots 20 and serve as an additional guide for the ring during its extension movement. In addition the projections 26 permit the proper alignment of the parts to be assembled. In some instances it may be desirable to use the thrust ring 14 as a release for a timing mechanism (not shown) adjacent the projectile bottom 3 In this case the thrust ring 14 is extended beyond the projectile bottom 3 in order to release the mechanism, for example a primer or a similar fuse, when being moved into its operating position.

The method of operating the device of the invention is as follows:

When the projectile is ejected from the firing tube 1 in the direction of the arrow F, the tail fins in the retracted state (fin 16 in FIG. 1) will bear on the outside jacket or casing 2 of the projectile body. When the projectile 50 moves beyond the end of the tube, so that the retracted fin assembly 16 clears the edge of the tube, the compression spring 12 will move the thrust ring 14 rearwardly so that the web 17 will be moved outwardly by the configuration of the cone 6 to position the tip plates 19 at a spaced location from the casing in the extended position 16a indicated at the lower portion of FIG. 1. During this time the fin base 18 or foot runs with its projection 24 into the recess 9 of the cone shell 7 and it is held in a form locking engagement by the edge 23 of the thrust ring 14 which falls into the recess 22. In addition, the compression spring 12 constantly stresses the tail fins even in the extended position through the thrust ring 14 to ensure force locking of these fins in the operative extended position.

Claims

What is claimed is:

1. A guide fin assembly for a flying body or projectile which is adapted to be ejected from a tube or receptacle, comprising a guide fin of a configuration which is adapted to conform to the peripheral surfaces of the projectile with which it is associated so that it can be held in juxtaposition therewith by a surrounding tube, a radially extending web connected to said guide fin for supporting said guide fin and for moving it outwardly from the projectile and for supporting it in an extended position spaced outwardly from the projectile, an oblique guide surface adapted to be located within the projectile and extending longitudinally and radially outwardly toward the rear end of the projectile, said web having an inner end engaged on the oblique surface and being movable along said surface in a radial direction during extension so as to be guided outwardly by said surface into an extended position, a thrust collar arranged around said oblique surface and engaged with said web in a manner permitting radial moving of said web with respect to said thrust collar, and biasing means acting on said thrust collar and urging it toward the rear of said missile in a direction to move said webs with said collar rearwardly and radially outwardly.

2. A flying body construction including a tubular outer casing, a guide fin of the same configuration as said casing adapted to overlie and conform to the casing, said casing including a slot defined therein extending substantially longitudinally, a supporting web connected to said guide fin and having an inner end extending through said slot into said casing, a guide surface in said casing extending longitudinally and radially outwardly toward the rear of said casing and engaged with the inner end of said web for deflecting said web outwardly with said guide fin during rearward movement of said web, a thrust collar surrounding said guide surface and connected with said guide fin web in a manner permitting radial movement of said web, and means to move said thrust collar in a direction to cause said guide fin to move rearwardly over said guide service and radially outwardly to cause the extension of said guide fin from outer surface of said casing whenever the guide fin is not held in juxtaposition with such casing.

3. A flying body construction, according to claim 2, wherein said means to move said thrust collar in a direction to cause the guide fin to move outwardly from the casing includes a compression spring, said guide surface comprising a hollow conical member arranged within the casing of said projectile, said web including a portion riding over the surfaces of said conical member and being deflectable outwardly when said web is moved in a direction to extend said guide fin, said compression spring being compressed when said guide fin is held in a position in juxtaposition with the casing of said flying body.

4. A flying body construction, according to claim 2, wherein said guide surface is of conical configuration, said web having a portion in contact with said conical portion and being movable outwardly thereby when said guide fin is not held in juxtaposition with said casing, said means to move said web comprising a compression spring which is compressed when said guide fin is held in a juxtaposition with said casing.

5. A flying body construction, according to claim 4, wherein said a thrust ring extending around said conical guiding means, said compression spring comprising a coil spring at one end held by said thrust ring, said thrust ring defining an abutment for said web, said compression spring being compresseible within said casing to permit forward movement of the thrust ring with said web along the conical portion of said guinding means, said spring being expansible to move said thrust ring rearwardly to move said web along said conical portion of said guiding means to cause it to move radially outwardly, and menas engageable with said ring in an extended position to hold said ring with said web and said guide fin in an extended position.

6. A flying body construction, according to claim 5, wherein said web includes a base portion which is guided on said conical portion and which includes a surface which conforms to the conical portion and which is engageable with notch means when it moves along said conical portion to an extended position.

7. A flying body construction, according to claim 5, including a plurality of webs extending radially outwardly from said flying body casing, said flying body casing having a longitudinal slot for each of said webs, a guide fin associated with each of said web members, each of said guide fins being of a considerable arcuate extend and occupying a major portion of the periphery of said casing when said guide fins are held in juxtaposition therewith.

8. A flying body construction, according to claim 7, extends a thrust ring extending around said conical portion of said guiding surface and being axially displaceable within said casing, a compression spring biasing said thrust ring to a rearward direction, said thrust ring having a guide face engageable with the interior wall of said casing and including a projection engageable with the slot of said flying body casing for guiding said thrust ring during its extension movement.

9. A flying body construction, according to claims 2 including a reaction motor carried within said casing of the flying body having a nozzle portion of conical configuration forming said guiding means for said guide fin assembly.