US2923549A

US2923549A - Tow target launcher for use on airborne vehicles

Info

Publication number: US2923549A
Application number: US543966A
Authority: US
Inventors: Robert J Hopper; Mar Bruce E Del
Original assignee: DEL MAR ENGINEERING LAB Inc
Current assignee: DEL MAR ENGINEERING LAB Inc; DEL MAR ENGINEERING LABORATORIES Inc
Priority date: 1955-10-31
Filing date: 1955-10-31
Publication date: 1960-02-02
Anticipated expiration: 1977-02-02

Description

Feb. 2, 1960 R. J. HOPPER ETAL 2,923,549

TOW TARGET LAUNCHER FOR USE ON AIRBORNE VEHICLES Filed 001. 31, 1955 2 Sheeis-Sheet 1 ROBERT J. HOPPER 6 BRUCE E. DEL MAR,

IN V EN TORS.

A TTORNE X Feb. 2, 1960 R. J. HOPPER ET AL 2,923,549

'row TARGET LAUNCHER FOR USE ON AIRBORNE VEHICLES Filed Oct. 31, 1955 2 Sheets-Sheet 2 az 3a 55 45 40 42 3a 28 65 a0 J'fifit. 66

r x r /a 44 15 75% 54 j 75 as Q g 30 ROBERT J. HOPPER &

BRUCE E. DEL MAR,

INVENTORS.

ATTORNEY United States Patent TOW TARGET LAUNCHER FOR USE ON AIRBORNE VEHICLES Application October 31, 1955, Serial No. 543,966 6 Claims. (Cl. 273105.3)

This invention relates to means for use on an airborne vehicle to transport an aerial target in snubbed position and to launch the target therefrom on a tow cable for a target run.

The invention is particularly adapted for use with an aerial target of the type disclosed in the copending Hopper application, Ser. No. 471,234, filed on or about November 26, 1954. Targets of the type shown in this prior disclosure are used in various types of aerial gunnery practice and are preferably of low density, low strength material. It is to be understood, however, that targets of various types may be used with the present invention.

The preferred practice of the invention disclosed herein is directed specifically to What may be termed a oneway launcher which launches the target on a tow cable and subsequently discards both the target and the cable. It will be apparent, however, that various novel features of the invention may also be incorporated in launching devices that are intended to recover the tow cable alone or the tow cable along with the target. 7

The presently selected embodiment of the invention is in the form of a self-contained remotely controlled targetlaunching unit that may be adapted to any airborne vehicle.' The remote control station may be on the airborne vehicle itself when the airborne vehicle is a manned aircraft or the control station may be at a distance from the airborne vehicle either on the ground or on a remote manned aircraft. i

In accord with the teachings of the invention, the unit includes a support structure that is adapted for mounting on'an airborne vehicle for engagement with the target at the snubbed position of the target and also includes a cable reel carried by the support structure. The tow cable is wound on the reel when the target is in its snubbed position and the reel rotates to pay out the cable when the target is launched. In the preferred practice of the invention, a first remotely controlled means releases the target from the support structure for unreeling of the cable and, at the end of a target run, a second remotely controlled means releases the cable from the reel for jettisoning both the cable and the target.

The leading end of the snubbed target is seated or nested in the support structure and the target is releasably retainedfin this position by suitable releasable anchorage means during the flight of the airborne vehicle to the target area.- The releasable anchorage means is attached to the support structure of the unit and may be either directly connected to the target to hold the target in snubbed position or may be directly connected to the reel for the same purpose. In this regard, a feature of the invention is the use of remotely controlled means to cause release of such an anchorage means. In one practice of the invention, the releasable anchorage means is an elongated tension member and the remotely controlled means causes rupture thereof. For this purpose, an electrically energized heating means may be provided, for example, to raise. the temperature of the anchorage means sufliciently to cause it to fail. In this manner, release of the target from its snubbed position is accomplished without using any moving mechanical parts whatsoever. A further feature of the preferred practice of the invention is the employment of a similar remotely controlled means at the end of the target run to rupture the leading end of the unreeled tow cable for jettisoning both the tow cable and the target.

It is contemplated that the unit may further include means to retard or regulate the speed at which the reel rotates in response to the load on the cable in the unreeling operation. The load or drag on the cable progressively increases as the cable is unwound because of the progressive increase in the total surface area of the cable that is exposed to air friction. At the same time, however, the effectiveness of the cable load for applying torque to the reel progressively decreases as the diameter of the cable winding decreases to shorten the moment arm involved. It has been found that these two oppositely changing factors compensate for each other to such an extent that satisfactory control of the rate at which the cable is payed out may be achieved simply by providing substantially constant resistance to the unwinding rotation of the reel.

In the preferred practice of the invention, retardation of the rotation of the reel is accomplished by operatively connecting the reel to a self-contained hydraulic device which performs work on a confined body of liquid. A substantially constant retardation effect is achieved by selecting a liquid having minimum viscosity change with change in temperature and by air cooling the hydraulic device to minimize the rise in temperature of the liquid.

A further feature of the selected embodiment of the invention is that the support structure of the launching unit is a housing of tapered configuration that may be substituted for the usual conical fairing on the trailing end of a wing fuel tank. Thus the invention makes it a simple matter to adapt many different types of aircraft for service in towing targets.

The various features and advantages of the invention may be understood from the following detailed descrip: tion considered with the accompanying drawings.

In the drawings which are to be regarded as merely illustrative:

Figure l is a fragmentary perspective view of an aircraft fitted with a unit of the present invention;

Figure 2 is a longitudinal sectional view of the unit;

Figure 3 is a longitudinal horizontal section taken as indicated by the line 3-3 of Figure 2;

Figure 4 is a transverse section taken along the line 4-4 of Figure 2 showing the reel and associated speed regulating device in elevation;

Figure 5 is a fragmentary view showing a second form of anchorage means directly tied to the reel for holding the target in snubbed position; and

Figure 6 is a fragmentary view showing how a remotely controlled latch may cooperate with the reel to hold the target in snubbed position.

Figure 1 shows how an embodiment of the invention in the form of a self-contained unit may replace the usual fairing on the trailing end of a wing fuel tank 10 of an airborne vehicle to transport and launch an aerial target T. As may be seen in Figure 2, the nose of the target T is provided with an attachment ring 12 which is connected to the end of the tow cable 14. The tow cable 14 may be of any suitable material but in this instance comprises a length of piano wire. 7

The unit includes a support structure comprising a tapered housing, generally designated 15, and a rearwardly extending framework unitary therewith. The framework includes a forward ring member 16 which, as

, bestshown in Figure 1, is unitary with the housing and trailing fairing of the fuel tank.

rearwardlyv converging directions.

which the leadingend of the target T is seated or nestedv when the target is in its snubbed position for transportaion, as may be seen in Figure 1.

As bestshown in Figure 2, the housing 15 conforms tothe taper ofthe usual skirt22 at the end of the fuel tank and is mounted on the skirt to replace the usual In the construction shown, the tapered housing is attached to the fuel tank skirt 22 by suitable rivets 24.

As shown inFigures 3 and 4, the tapered housing 15 encloses a reel generally designated 25 and a speed-regulating device, generally designate-d 26, wh ich is opera- 4 a I i cable may be connected to the attachment ring 12 on the nose of the target T. Preferably, the nylon cable 64 which is drawn taut presses sidewise against a flanged stud 65 on the side of the reel 25 in such manner as to tend to rotate the reel in its winding direction. Thus the tow cable 14 is also maintained taut.

It is contemplated. that suitable.- remotely controlled means will be provided to cause the nylon cable 64 to 1 release the target T and to permit the reel 25 to pay out the towcable 14when the desired target area is reached. Various means may be provided for this purpose. In the present embodiment of the invention a remotely controlled electrically heated element .66 is provided for the application of heat to the nylon cable 64 to cause tively connected to the reel to restrain .the'rotation thereof 7 in the paying out of the tow cable 14. In the preferred practice of the invention the speedregulating device 26 is a hydraulic device which confines a body of viscous liquid and acts on the liquid in response to rotation of the reel. Preferably a liquid is used such as a silicone liquid, the viscosity of which changes but little in response to change in temperature. In this regard a feature of the present embodiment of the invention is the conceptof air-cooling the hydraulic device 26 to keep the temperature of the confined liquid from rising unduly.

To provide air cooling, a portion of the housing 15 is ofisetfrom the tapered configuration to provide'a down-1 wardly, extending airscoop having a'bottom wall 28 and two side walls 30. The two side walls 30 are tangential to the conical portion of the housing. 15 and extend Figure 13', the air scoop formed in this manner hasa. forward inlet opening .32 at the forward edge of the bottom wall 28' and has a larger rearward discharge. open-. ing 34'. Thus the airscoop is adapted to divert a portion of the airstream adjacent the housing into the interior; 40

of the housing to pass over the hydraulic 'device 26.

I Preferably, the hydraulicdevice 26 is mounted on the bottom wall 28 of the air scoop and carries the reel 25. In the construction shown, the hydraulic device is mounted on a basestructure 35,v the latter being attached to'the bottom wall 28 of the scoop by suitable bolts 38. Anupright spindle. 40 is. welded to the base structure 35 and has keyed thereto a suitable sleeve'42 on which the housing 44. of the hydraulicdevice is rotatably mounted by suitable bearings 45. The ,fixed sleeve 42 has'a central collar 46' united therewith and this collar carries a pair of spaced thin rings or radial wall members 48. These fixed radial wall members provide relatively large surfaces in contact with the viscous liquid with which the housing is filled. The rotary. housing 44 of the by: I

draulic unit is made in two sections, as shown inFigure 3, between which is sandwiched a third thin ring or radial wall member 50 which also has extension surfaces immersedin the viscous liquid.

For the purpose-of mounting the reel 25 on the housing '44 of the hydraulic device 26for rotation therewith, an axial post 52 is provided. T his'post has-a radial flange 54 at,its inner. end by .means of which it is. rigidly mountedonthe side ofthehousing 54, for example by suitable screws 55. The reel 25 has a tubular axial por: tion56 for mounting on the post SZ-andthe reel isheld in place by a suitable washer 58 in cooperation witha cap. screw 60 that is threaded into the end of the post; The tubular portion 56 of the reel is providedwith a suitable key 62 inengagement with the post 52. to cause the reel to rotate in unison with the post andthe housing I 44 of the hydraulic device 26.

Any suitable anchorage means may be used t'odhold the targetT in the snubbed position shown. in thedrawing. For example, as shown in Figures 2, 3 and 4, an.

elongated .anchoragemeans 64in the formofianylon As bestv shown in,

rupture thereof, nPreferably as shown in Figure 2,. a suitable leaf spring 70 is mounted inside the tapered housing 15 in a position to be flexed inwardly by the tow targetT. when the tow target is in its snubbed position: sothatwhen the nylon cable 64 is ruptured, the. spring thrusts the target rearward from the supportstructure into the airs tream. The end of the leaf spring may form asmall ring 71 to seat against the nose of the target T.

The heating element 66 for rupturing the nylon. cable 64 may comprise a well known type of heatingcoil mounted on a pair of bracket members 68. The taut nylon. cable. 64.passes around the heating element 66 and is-connected at its end to a suitable fixed member 69,-insidethe unithousing 15.

Preferably the invention further includes means to releasetheunreeledtow cable 14 from the reel 25 atthe endof the target run. for the purpose of jettisoning both the target and thetow cable. Various means may be' provided fonthis purpose. In the present practiceof the invention;. for. example, a suitable electrical conductor 72 is.mounted..on a pair of. brackets 74 for contactwith the. piano .wire. tow cable14 at a point thereon closetto. thereel 25. The reel is grounded to serve as partof an electrical circuit:which includes: the conductor 72 and the short portion of the piano wire tow cable 14 be-; tween the conductor and the reel 25. When the'circuit;

is closed, sufiicient current flowsthrough the portion of.

i the piano wire cable .14 between the conductor 72 andthe reel 25 to' cause-this portion of the tow cable to weaken and pull. apart under the tension caused by load on the.

cable.

The circuit for energizing the heating element 6 6 and 1 the circuitv for energizing the conductor 72 may be. re-" 1 motely controlled to close in sequence, first, for launching the target T, and, second, for jettisoning the tow cable 64. For this purpose, a sequential switch or relay 75 may be mounted inside the tapered housing 15, the sequence switch being connected to the heating element.

by a wire 76 and being connected to the conductor 72 by a second wire 78. The sequence switch 75 is initially operated by remote control to close the circuit through the heating element 66 to release the target and at the end of the target run the sequence switch 75 is again operated to close the circuit through the conductor 72.

The sequence switch 75 may be connected by a suitablecable .(not shown) to a control station on the aircraft itself if'theaircraft is a manned aircraft. On the other hand, if the airborne vehicle carrying the unit is. not

manned, the sequence switch'75 may be controlled from a remote station by radio in a well known manner, the

remote station being either on the ground or on a remote manned aircraft. 7

The manner is which the invention serves its purpose may be'understood from the foregoing description. For transportation of the tow target T to a targetarea, the target is movedinto its basket seat or cradle inthe sup! portstructure of the unit in opposition to the leaf spring 7t) andis held in position by the, nylon cable 64. The

nyloncable 64is pulled taut and anchored to the fixed member; '69 with the-nyloncable exerting force laterally against the'flan'ged stud 65 to z urge the reel 25 in" a clockwise direction as viewed in Figure Z. ;At this position of the reel, the tow. cable 1 4 is pulled taut to minimize the possibility of the tow cable snarling when the target is subsequently released by the nylon cable 64.

When the desired target area is reached, the sequential switch 75 is actuated by remote control to cause energization of the heating circuit through the heating element 66 that is in contact with the nylon cable 64. As a consequence, the nylon cable 64 is heated to a de- .gree to cause it torupture thereby both releasing the target and freeing the reel for unwinding rotation. The rupture of the nylon cord 64 permits the leaf spring 70 to thrust the target T rearward from its seat and causes the reel 25 to start to pay out the tow cable. When the target T is thrust into theairstream, it immediately places the tow cable 14 under substantial tension to cause the tow cable to unwind. The reel unwinds at a retarded rate by virtue of the hydraulic device 26 until the second end of the cable is reached, the second end being attached ;to the reel.

At the end of a target exercise, the sequential switch '15 is again actuated to cause the circuit to be closed through the conductor 72. Since the conductor 72 is in contact with the piano wire tow cable 14 and since the reel 25 is grounded, current flows through the short portion of the tow cable between the conductor and the reel. The flow of current is sufficient to raise the temperature of the tow cable to a point at which the load placed on the tow cable causes the tow cable to pull apart and drop away from the unit.

Figure 5 shows a modification of the invention in which no anchorage means whatsoever is connected directly to the tow target. Instead an anchorage means 80 in the form of a nylon cable is connected directly to the reel itself to prevent the reel from unwinding, the reel being maintained stationary with the tow cable 14 taut. Thus the tow cable alone holds the target in snubbed position and the nylon cable 80 holds the reel 25 in the wound position with the tow cable taut. The nylon cable 80 is in contact with the heating element 66 in the same manner as heretofore described so that energization of the heating element causes the nylon cable to rupture and thereby release the reel for unwinding the tow cable.

Figure 6 shows how a remotely controlled electrically actuated latch 82 may be substituted for the nylon cable 80 to hold the reel 25 in a position with the tow cable 14 taut and with the target in its snubbed position. In Figure 6, a reel 25a is provided with a series of circumferential ratchet teeth 84 for cooperation with a latch member which comprises an armature S5 of a solenoid 86. The latch member 85 normally engages the ratchet teeth 84 in the manner shown in Figure 6, the latch member'being held in this position by concealed spring means. When the solenoid 86 is energized, the latch ,member 85 is retracted to release the reel 25a for unwind- 'ing rotation. The solenoid 86 replaces the heating element 66 in the electric circuit that is controlled by initial operation of the sequential switch 75.

Our description in specific detail of the present preferred practice of the invention will suggest various changes, substitutions and other departures from our disclosure that properly fall within the spirit and scope of our appended claims.

We claim:

1. A device for use on an aircraft to transport an elongate rigid aerial tow target in snubbed position to a target run area and to launch the target for tow by the aircraft during flight thereof in the target run area, comprising: support structure to be fixed to the aircraft and including a rearwardly facing cradle to supportingly nest at least the forward portion of the target in its snubbed position with a major portion of the target in the airstream adjacent the aircraft to be acted upon by the airstream; a reel rotatablyecarried by said support structure to be wound with a tow cable. when the target is in its snubbed position with the forward portion of the target supportingly nested by said cradle; means coupled to the support structure to releasably retain the target in its snubbed position as said aircraft flies to said target run area, said coupled means making positive engagement directly with said reel at a point spaced substantially from the axis of the reel to immobilize the reel; means remote from said support structure for releasing said target-retaining means for release of the target and release of the reel for rotation as said aircraft approaches said target run area, whereby the cable unwinds from said reelunder the drag of the target for tow by the aircraft; means carried by said support structure for severing the tow cable whereby the aircraft may return to a selected landing field free of said target and tow cable; and means operable from a station remote from said support structure for activating said severing means.

2. A device for use on an aircraft for supporting thereon an elongate rigid target in flight of the aircraft to a target practice run and for launching the target for tow by the aircraft; comprising: a support structure to be mounted to the aircraft and defining a cradle facing rearwardly of the aircraft for engagingly receiving and supporting at least the forward portion of said target with a major portion of the target in the airstream adjacent the aircraft to be acted upon by the airstream; a length of cable having one end thereof secured to the forward portion of said target; a reel rotatably supported on said structure to which the opposite end of the cable is secured and upon which said cable is wound when the target is supported by said cradle; releasable means for direct positive engagement with said reel at a point spaced substantially from its axis of rotation to hold the reel against rotation in a direction to unwind said cable therefrom to thereby retain said target with its forward portion engaged with said cradle for support thereby as said aircraft flies to the area of said practice run; means for releasing said releasable means to free said reel for rotation as the aircraft is-flown into said target practice run, the reel being rotated by the tension forces in the cable created by the drag of the target, whereby said target is launched for tow by said aircraft during said target practice run; and means for releasing said cable from the aircraft to free said aircraft from said cable and target, said last named means being operable from a station remote from said support structure.

3. A device for use on an aircraft for supporting thereon an elongate rigid target as set forth in claim 2 in which said releasable means includes a circumferential series of ratchet teeth rotatable with said reel, latch means for engagement with said teeth and yielding means normally holding said latch means in its effective teethengaging position; and in which the releasing means comprises remotely controlled means to retract said latch means in opposition to said yielding means to free said reel for rotation.

4. A device for releasably holding an elongate rigid aerial tow target of a forwardly tapered streamlined configuration to an aircraft, comprising: a support structure to be mounted to the aircraft, said structure including a rearwardly facing cradle for supportingly nesting at least the forward portion of said target with a major portion of the target in the airstream adjacent the aircraft to be acted upon by the airstream; a reel rotatably carried by said support structure upon which is wound a length of cable having the one end thereof connected to the forward portion of said target and the opposite end thereof connected to said reel, said cable being wound upon said reel when the target is supported by said cradle; means for direct positive engagement with said reel at a point spaced substantially from its axis of rotation for retaining said reel against rotation to hold said target in its support position on said cradle; means carried by said support structure and engaged with the nose of-saidtarget when supported by said cradle for resiliently urging said target rearwardly of saidcradle'; remote control means for releasing said reel-retaining means, whereby said urging means resiliently thrusts said target rearwardly, thedrag of said target unwinding the cable from said reel; and means permanently operatively connected to said reel and immersed in a body of liquid to absorb energy to retard the rate of rotation of said reel as said cable is unwound therefrom under thedrag of the target in the towed flight thereof.

5. A device for use on an aircraft to transport an aerial tow target in snubbed position'to a target run area and to launch the target for tow by the aircraft during flight thereof in the targetrun area, comprising: support structure] to be fixed to the aircraft and including a rearwardly facing cradle to supportingly nest atleast the forward portion ofthe target in its snubbed position; a reel rotatably carried by said support structure to be wound with a tow cable when the target is in itssnubbed position with the forward portion supportingly nested by said cradle; an elongated means coupled tosaid support structure to anchor a portion of said reel to the support structure to releasably retain the target in its snubbed release the target whereby the cable unwinds from said reel" under "the drag of the target for tow by the air craft; means carried by said support structure for severing the tow cable whereby theaircraft may return to a selected'landinggfieldfree of said target and tow cable; and means operable from a station remote from said support structure foractivating said severing means.

position as said aircraft flies to said target run area;

remotely controlled means to cause rupture of said elongated means to release the reel for rotation and thereby ii 6L'A combination as set" forth in claim' S in which said remotely controlled rupture means is an electrically energized means to heat said elongated member thereby to cause rupture thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,137,450 Green 7,0,, Nov. 22, 1938 2,272,213 Lear Feb. 10, 1942 2,410,451 Landry Nov. 5, 1946 2,432,371 Berberich Dec. 9, 1947 2,460,194 Schultz Jan. 25, 1949 2,495,732 Jessen Jan. 31, 1950 2,499,012 Welsh Feb. 28, 1950 2,502,650 Harris Apr; 4, 1950 2,751,167 Hopper June 19, 1956 2,760,777 Cotton Aug. 28, 1956 2,813,719 Hopper 'Nov.19, 1957 FQREIGN PA N S 6 7 20 Great Br a n b- 27 1 52