US2957417A

US2957417A - Missile decoy

Info

Publication number: US2957417A
Application number: US771845A
Authority: US
Inventors: Daniel D Musgrave
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-11-04
Filing date: 1958-11-04
Publication date: 1960-10-25
Anticipated expiration: 1977-10-25

Description

1960 D. D. MUSGRAVE 2,957,417

MISSILE DECOY Filed NOV. 4, 1958 INVENTOR United States Patent O 2,957,417 .nnssmnnncoY Daniel D. Musgrave, 8201 Caraway St., Cabin John, Md. Filed Nov. 4, 1958, Ser. No. 771,845 2 Claims. (Cl. 102-50) This invention relates to a decoy system for use on a missile or rocket. It will be disclosed herein as applied to an air-to-air missile but it is not limited to such use. The range of utility of the device will depend on tactical considerations.

It is well known that many missiles are capable of homing on objects which emit infra-red radiation. That such missiles must have tunnel vision is obvious, otherwise they might seek the sun. If there be more than one radiating object within the homing cone of the missile, what point it will target on will depend on the intensity, distance to, and distribution of the several radiant sources.

The role of the missile in air combat is to destroy the enemy plane. In this it seems to have supplanted the machine gun. The machine guns of bombing aricraft were considered defensive weapons whose purpose was to permit the plane to fight oil interceptors and continue on to the bomb target. To increase their defensive ability, these machine guns were sometimes supplied with Headlight ammunition which, in addition to its normal ballistic effect, had an adverse morale effect on the pilots of attacking interceptors because its trace was visible from the direction of the target.

The primary object of this invention is to increase the effectiveness of certain types of missiles by giving them defensive capabilities in addition to their offensive potential.

Another object is to strengthen the defense of the large bombing plane by providing a missile which may act as a decoy at the critical time when the bomber is being attacked by missile-armed interceptors.

Another object is to intensify the attraction which certain missiles or rockets may exert for homing guided missiles approaching from a certain direction.

Other objects of the invention will be apparent from the description of the ivention as hereinafter set forth in detail and from the drawings made a part thereof in which:

Figure l is a perspective view of the invention as ap-' plied to the rear portion of a missile.

Figure 2 is a section view of the invention taken in the plane indicated by line 2-2 in Figure 1.

Figure 3 is a schematic view to show the relationship of certain technical and tactical characteristics of missiles and planes in an air-to-air combat situation.

Referring to Figure 1 more in detail, there is shown a missile 1 having rear stabilizing fins 3 afiixed to it as by welding. The number of stabilizing fins 3 is immaterial but in this case it happens to be four. To the fins 3 is aflixed, as by welding, a shroud 5 which in this case consists of two quarter circle portions, each affixed to the extremities of a pair of fins. Missile 1 has a typical motor orifice 7 which lies along its longitudinal axis.

The internal surface of shroud 5 is indicated by numeral Referring now to Figure 2 it will be noted that shroud 5 is shaped as the outer portion of a theoretical paraboloid, the missing portion of which is indicated by broken "ice 2 line 11. The principal focus 13 of the theoretical paraboloid is .located immediately behind .motor orifice 7. The internal surface 9 of shroud 5 is polished to form a reflector which receives incident rays of infra-red or otherradiation from the vicinityof principal focus 'l3iand reflects them in the-direction toward which the missile is fiying. -A pair of reflectedrays areshown at 15 and 17.

The missiles course may be set in the well known manner by guidance fins 19.

In Figure 3 there is shown schematically a pursuit situation involving a bomber 50 and an interceptor 59, both armed with missiles. It will be assumed that both planes travel at the same speed and release their missiles simultaneously. It will also be assumed that both missiles have equal performance capabilities.

Bomber 50 is assumed to have

engines

51, 52, 53 and 54, with interceptor 59 as a vertex, define an angle, 58, which will tend to increase as the distance from the vertex to the outboard engines is decreased. We will assume that interceptor 59 is armed with, and launches, a missile, 57 in an attempt to destroy bomber 50.

From an extreme range missile 57 will find the included angle between

engines

51 and 54 small, and will be unable to distinguish separate radiation sources. As missile 57 approaches target the included angle between

engines

51 and 54 will exceed its filed of vision and it will become selective and narrow its choice to include the more intense radiation sources. When it strikes a multiengine target presumably it will hit the hottest engine.

Bomber 50 is assumed to be armed with, and has launched a missile 56, with interceptor 59 as its target. Missile 56 is assumed to be equipped with the decoy apparatus shown in Figs. 1 and 2.

Missiles

56 and 57 were released at the same time but 57 approaches target first because its acceleration is added to the speed of interceptor 59. Missile 56 is at a disadvantage since its acceleration must overcome the negative speed of bomber 50. Accordingly, they do not approach each other midway to target but somewhat as shown in Figure 3.

Since missiles are driven by heat engines they themseleves are radiation sources, but the radiation is normally dissipated in all directions with the least going to the front. By means of its decoy apparatus missile 56 directs an intense beam of rays forward causing missiles 57 to home on its and both missiles are destroyed. If either plane carries a second missile it may launch now to try for a kill.

As stated above the range of utility of this invention will depend on tactical considerations. The example cited is but one of a vast number of possible combinations of course and speed for the opposing aircraft. The missiles too may vary in speed, fuzing, homing, programing and burnout time. If both combatants use missiles having a decoy system new tactics may result.

It is desired to point out that changes may be made without departing from the spirit of the invention. The decoy might be applied to an unguided rocket. The shroud may form a complete circle about the fins, which may be of the folding or of the sliding type. The radiant source is not a true point source and the reflector might be conic or concave.

What I claim is:

1. On a missile having stabilizing fins and a reaction thrust motor, a decoy system comprising a shroud fixed to the fins of said missile having an internal reflective surface of partial parabolic shape with its principal focus subtantially on the axis of said motor and adapted for directing radiation from said motor in a direction opposite to the thrust of said motor.

2. On a missile having stabilizing fins and a reaction thrust motor, a decoy system comprising a shroud fixed to the fins of said missile having an internal concave reflective surface with its principal focus substantially on the axis of said motor and adapted for directing radiation from said motor in a direction opposite to the thrust of said motor.

References Cited in the file of this patent UNITED STATES PATENTS 2,510,147 Skinner June 6, 1950 2,642,777 Bradler June 23, 1953 2,737,356 Varian et a1 Mar. 6, 1956 OTHER REFERENCES Klass, P. 1.: Exclusive. Report on Infrared, reprinted from Aviation Week, March 4; 11, and 18, 1957, pub- 10 lished by McGraw-Hill Publishing Company.