US 3622103 A
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United States Patent 72 inventor Heinrich Meier Rumlang, Switzerland 004 3 al 23 B 4 4 4 4 2| 2 k C a m H m m w 4 .VJ. m m m m w m w& n d l vi -l n fa e U.l BTCB m h 2669 0 3366 l 9999 we //HH.m m 962 me w O996 4 78 V .3 U 9428 mm 7497 no nu 233 PA n 0 .m l r e O .m r. b m e d m n .l 28 Q: 1gGW n 'u S a m su lunm nj nk w 8l mu m .w m3 3u u 0 B JNWBZJS 0. de N m m w n i 05 f Wemfle .m "a r AFPA P flfifl NIHH 2247 333 ABSTRACT: Twistless projectile with launching tube having stabilizing, preferably braking, fins pivoted on pins which are arranged perpendicular to the longitudinal axis of the projectile and secured to a support arranged aft of the projectile base, so that the fins can swing from a rest position. in which  TWISTLESS PROJECTILE WITH LAUNCHING they project forward, into an action position, in which the TUBE project rearward. The fins constitute segments of a hollo 2 Claims, 2 Drawing Figs. rotational body which completely envelops the projectile body in the rest position and at least partially rests against the pro- [521 US. jecme body- The fins have ouwardmmjecfing ridges which F42.) 13/32 together form a closed guide ring sealing against the launching 244/3 28 tube. The projectile body tapers in its rear portion and the fins 3 29 3 02/4 35 4 5 are provided on the inside with annular shoulders which in the  Field oi Search..................
rest position rest rearward against a flange ofthc tapering portion of the projectile.
PATENTEUN 23 3.622.103
INVENTOR HEINRICH MEIER 7 TWISTLESS PROJECTILE WITH LAUNCHING TUBE The present invention relates to a twistless projectile with launching tube, comprising stabilizing, preferably braking, fins pivoted on pins which are arranged perpendicular to the longitudinal axis and secured to a support arranged aft of the projectile base, so that the said fins can swing from a rest position, in which they project forward, into an action position, in which they project rearward.
in a known projectile of this type (see US. Pat. No. 3,306,199), the fins are made of metal strips which are substantially flat and spaced sideways from one another, so that together they do not completely envelop the projectile body. Such projectiles, which are dropped or ejected from containers attached to an aircraft, are not suitable for being propelled in a tube by a gaseous propellant and launched therefrom. Gas can escape between the individual fins and between the fins and the projectile body, so that the pressure difference between the propelling end and the other end of the projectile is at least partially equalized.
The object of the present invention is therefore to provide a projectile suitable for being launched from a tube by a gaseous propellant, i.e. capable of sealing off the tube space containing the propellant. The invention is characterized in that the fins constitute segments of a hollow rotational body which completely envelops the projectile body in the rest position and which at least partially rests against the projectile body, and have outward-projecting ridges which together form a closed guide ring sealing against the launching tube.
An embodiment of the invention is illustrated by way of example in the attached drawing, in which:
FIG. 1 shows a longitudinal section through a launching tube containing a projectile, with the projectile shown partly in section and partly from outside;
FIG. 2 shows a view in the direction of arrow F in F 1G. 1.
A projectile 1 is slidably held in a tube 2. The projectile body presents a cylindrical front portion 3 and a rearwardtapering rear portion 4. The rear portion 4 of the projectile body presents a projection 5 in the form of a flange whose face 6 is perpendicular to the projectile axis. A cap 7, closing the forward end of the projectile body, is semispherical. A diskshaped support 8 is arranged aft of the base 9 of the projectile body and perpendicular to the projectile axis. Four slots 10 are so incised into the support 8 that their planes of symmetry include the longitudinal axis of the projectile. The slots 10 are spaced at equal angular distances. The support 8 presents rearward'pointing projections 11. The end-faces 12 of the projections 11 form tangential planes of a sphere which has the same radius as cap 7 and whose center, like that of the cap 7, is located on the projectile axis. When several projectiles l are arranged in tandem in the tube 2, in a manner not further illustrated, the cap 7 of one projectile rests against the projections 1 1 of the support 8 of the forward projectile.
The projectile body 3, 4 contains an explosive charge 13 in which a central cylindrical channel 14 is left free. A conical bore 15 in the base 9 of the projectile body is coaxial with the channel-14 of the explosive charge 13. A rod 16 secured in the support 8 extends forward through the bore 15 and the channel 14 of the explosive charge 13. The forward end 17 of the rod 16 is conically enlarged forward.
In the rest position of the projectile 1 as shown in FIG. 1, the projectile body 3, 4 is completely enveloped by four plastic fins 18 of equal size. These fins 18 constitute segments of a hollow rotational body. The fins 18 are provided with holes 19 for the purpose of increasing the air resistance and have ridges 20 at their rear ends. The ridges 20 of all four fins 18 together form a closed guide ring 21, whose diameter is equal to the inside diameter of the tube 2. The fins 18, whose outside diameter forward of the ridges 20 is smaller than the diameter of the guide ring 21, rest against the cylindrical portion of the projectile body. Each fin 18 is provided at its forward end with a rib 22 which is parallel to the projectile axis and radial. The outer surfaces 23 of the ribs 22 are spaced from the projectile axis at a distance e ual to the radius of the ring 21.
The fins l are defined at the rear by a surface 24 arranged across the projectile axis. The projections 25 extend rearward from the surfaces 24 and engage the slots 10 of the support 8. The projections 25 and, accordingly, the fins 18 are pivoted on the pins 26, which are arranged perpendicular to the projectile axis and secured in the support 8. The fins 18 have a conical surface 27 on the inside. These surfaces 27 adjoin the rear portion 4 of the projectile body, thus defining the foremost position of the fins 18 and, accordingly, that of the support 8. The fins 18 rest with annular shoulders 28 on the face 6 of the flange projection 5 of the projectile body. This arrangement prevents the fins 18 from moving rearward rela tively to the projectile body 3, 4. A slit spring ring 29 rests against the bottom of grooves 30 arranged on the inside of the fins 18.
The action of the fins follows from the construction of the projectile:
A gaseous propellant, such as the combustion gases of a powder charge, acts from the front on the projectile 1 and accelerates the latter rearward in the tube 2, Le. downward as viewed in FIG. 1. In the process, the propellant also acts on the end-faces 31 of the fins 18 and on the face 32 of the guide ring 21 formed by the ridges 20 of the fins 18. These gas forces acting on the fins 18 are transmitted by the shoulders 28 to the flange 5 and, accordingly, to the projectile body 3, 4.
The guide ring 21, which has only little clearance with the tube 2, acts as a seal, preventing any gas from getting from the front to the rear of the projectile 1. The guide ring 21 also serves in conjunction with the ribs 22 to guide the projectile 1 in the tube 2. When the projectile 1 leaves the tube 2 moved by an aircraft, it has, with respect to the tube 2, a relative velocity which is smaller than the speed of the aircraft. The projectile 1 therefore flies in the same direction as the aircraft, but at a substantially lower speed than that of the aircraft.
When the projectile 1 has left the tube 2, the fins 18 swing away from the projectile body 3, 4 under the action of the spring ring 29 and are subsequently swung rearward about the pins 26 under the pressure of the air flowing towards them. As the fins 18 are no longer secured by the flange projection 5 of the projectile body, the air pressure pushes them rearward together with the support 8. This translation movement of the fins 18 is stopped by the fact that the tapering projection 17 of the rod 16 moving rearward in the explosive charge 13 comes up against the wall of the bore 15. At the end of their swinging and translation movement, the fins 18 take up the position shown dash-dotted in FIG. 1, in which they form an acute angle with the rearward-extending projectile axis. In this position of the fins 18, the air forces acting thereon have a stabilizing and slowing effect on the projectile 1. The spacing of the fins 18 from the projectile body 3, 4 has the advantage of increasing the stabilizing effect of the air forces.
1. Twistless projectile with a launching tube comprising a projectile body having a conical rear end, a slidable support at the rear end of said conical portion, bolts positioned at right angles to the projectile axis in said support, braking fins pivotally mounted on said support on said bolts, whereby said support and said fins are movable from a rest position towards the rear into a working position, said fins comprising segments which in the rest position form a hollow cylinder completely enclosing said projectile body, projections on said fins, a flange on the conical end of said projectile body which cooperates with said projections, said projections in the rest position of said fins lying on said flange and preventing said fins against backward movement over said projectile body and wedging gas tightly said fins between said conical end of said projectile body and said tube.
2. A projectile as set forth in claim 1 wherein said fins have apertures therein to produce air turbulence to increase the braking action.
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