US2678214A - Nonrigid tow target - Google Patents

Description

W. B. BREWER, JR

NONRIGID TOW TARGET May 11, 1954 3 Sheets-Sheet 1 Filed July 18, 1952 INVENTOR. W/QLTEE 5 BREWER JE.

yam/MW? May 11, 1954 Filed July 18, 1952 VII w. B. BREWER, JR 2,678,214

NONRIGID TOW TARGET 3 Sheets-Sheet 2 INVENTOR. WfiL 75E 5 BEfWEE J15. a/Me 3 Wm If" HTTOE/YEYS May 11, 1954 Filed July 18. 1952 W. B. BREWER, JR

NONRIGID TOW TARGET 3 Sheets-Sheet 3 INVENTOR. WHLTEE B- BEfWfE JAE.

HTTQENEX? element.

Patented May 11, 1954 NONRIGID TOW TARGET Walter B. Brewer, Jr., East Aurora, N. Y., assignor to the United States of America as represented by the Secretary of the Air Force Application July 18, 1952, Serial No. 299,714

8 Claims.

This invention relates to tow targets for aerial gunnery and particularly to tow targets of the nonrigid type.

Tow targets for aerial gunnery are subject to rapid deterioration due to the violent oscillations of the flexible fabric or similar materials from which they are made.

To maintain these oscillations at as low a value as possible it is current practice to incorporate, in the design of the tow targets, appropriate aerodynamic stabilizing elements near the trailing end of the target thereby introducing a powerful factor toward suppression or elimination of the troublesome oscillations.

The invention has for an object the provision of means in the stabilizing elements which facilitate the storing and packaging of the target as well as assisting in the operation of launching through control of the rate at which the target is unfurled.

' (Ether objects and advantages of the invention will become apparent from the following description and accompanying drawings in which like reference characters refer to like parts in the several figures.

Fig. 1 is a schematic view of apparatus embodying my invention shown with the tow cable reeled in and the target furled.

Fig. 2 is a view similar to Fig.1 but with the tow cable payed out and the target partly unfurled.

Fig. 3 shows the flexible fabric target completely unwound and extended as it appears after the operation of the device.

Fig. 4 shows the outer or main torque tube upon which the flexible fabric target is rolled in readying the device for operation.

Fig. 5 shows an internally threaded cylinder which is constructed to contain a hydraulic fluid, there being means to force said fluid from said cylinder through a restricted outlet to retard unfurling of the target.

Fig. 6 shows a slotted torque tube sleeve which is adapted to transmit rotation from the torque tube to the internally threaded cylinder.

Fig. 7 shows an externally threaded piston arranged to remain nonrotative while engaging the internal threads of the internally threaded cylinder, whereby rotation of the said cylinder effects relative axial movement of the cylinder with respect to the piston.

Fig. 8 shows the drag element, which serves also as a container for the torque tube with the target wrapped around it. y

Fig. 9 is a horizontal section through the drag Fig. 10 shows one of the flexible loops with which the front of the target is provided.

Fig. 11 shows one of the flexible loops with which the rear end of the target is provided.

Fig. 12 is an assembly view of the parts which appear separately in Figs. 4, 5, 6 and 7.

Like reference characters refer to like parts throughout the several views.

The drag element 29, as shown in Fig. 8, comprises a framework consisting of vertically extending angle sections 22 supported by bulkheads 22: 3. One of the four corners of the drag element 28 is open in the form of a slot 28 which extends substantially throughout the entire length of the drag element. Guide strips 28 with the lower portion of V form and the upper portion circular are spaced longitudinally of the drag element with the bottom of the V open and in register with the slot 2c of the drag element. At the open bottom of the V the corners are rounded. The dimensions of the guide strips 28 should be such that the target when closely rolled around the torque tube will enter through the guide strips quite freely. The purpose of this construction is important as will hereinafter appear.

The target, see Fig. 3, consists of a piece of woven fabric 3i] which, for purposes of description, but not by way of limitation, may be about 6 feet wide by 30 feet long. Ihe front end of the target is provided with reinforcing loops 32, Fig. 10, these loops being provided to receive the spreader bar at from which the bridle lines as extend and by which they are held spaced apart. The bridle lines converge (see Fig. 3) and meet in a common point at 38 where they are connected to the trailing end of the conventional tow cable 40 carried on a reel on the towing plane. A weight 4-2 on the bottom end of the spreader bar keeps the target in a vertical plane.

At the trailing end the target Girl is provided with reinforcing loops t l, Fig. 11, these loops being provided to receive a torque tube it, Fig. 4-, with the target 30 wrapped closely around it. This torque tubaand-target assembly may be en" tered longitudinally into the drag element 2%} within the space surrounded by the guide strips 28, Fig. 9. The reason for the shape of the guide strips 28 will now be apparent, for when the target is rolled around the main torque tube and is in place in the drag element 2 3 within the guide strips 28, and is being pulled through the slot 26 to unreel it, the tube-and-target assembly bear against the V sides 29 of the guide strips thereby oifering considerable resistance to being un wrapped.

The main torque tube 46, both inside and outwith the main torque tube it. bled the torque tube sleeve 52 may neither roa 3 side, is of uniform diameter throughout its length. Within the main torque tube, intermediate its ends, there is a hollow internally threaded cylinder 48, Fig. 5, closed at one end and open at the other. An externally threaded piston ts, Fig. '1, on the end of a tubular shank 52, fits freely into the internal threads of the cylinder 4 .3. A bearing collared near the outer end of the shank E2 maintains concentricity between the shank 52 and the main torque tube at. A block 56 at the extreme upper end of one of the vertical angle sections'22 of the drag elementf c supports a rod 5%, the inner end of which extends intoa slot to to prevent rotation of the shank 52 with respect to the drag element 2E3, whereby rotation of the cylinder it relative to the piston moves the cylinder axially. A small hole 55 in the piston 59 permits a hydraulic, fluid to escape escape slowly and thereby retard axial movement of the cylinder 48 as it is screwed over the piston 58.

The torque tube sleeve Fig. 6, in the assessbled device, lies between the main torque tube 4% and the cylinder .48. The torque tube sleeve 62 is slotted as at 6 3, two slots being 186 degrees apart, and the cylinder ii; has two pins d8 circumferentially spaced 180 degrees, and registering with the slots M. Two longitudinally spaced rivet holes 58' in the torque tube sleeve or register with two equally spaced holes in the main torque tube. tend through holes 658 in the torque tube sleeve and the corresponding holes in the main torque tube 66 to join these tubular members for unitary rotation. Rivets "it should be finished flush with both the outside and the inside of the tube assembly. To facilitate entry of the pins be into the slots es, the open ends of the slots are flared outwardly as at it.

As finally assembled, see Fig. 12, the main torque tube it with the torque tube sleeve 62 In the complete assembly, rivets is ex- Next the pin 58 is withdrawn to allow the piston 58 with its shank 52, together with the cylinder 48, to be lifted out of the torque tube t6, and the cylinder 48 filled with a hydraulic fluid the piston to being screwed into place, and the subassembly 48-52 returned to its position in the main torque tube 46. As an alternative the piston 5t with its shank 52 may be removed without withdrawing the cylinder 48, the cylind'er in that case being serviced in situ. The pin this now returned to the position shown.

In the schematic view, Fig. 1, a towplane i2 is equipped with the conventional cable reel it upon which the tow cable #53 is substantially fully rolled, the trailing end of the tow cable 1 at being at 38. Bridle lines 36 have their leading now riveted therein is slipped over the internal- 1y threaded cylinder at with the pins 66 in the slots 6d, the piston 5b is started into the cylinder .48, and the main torque tube lii may be rotated,

thereby rotating the sleeve 52 and the cylinder E8, the piston 5%) remaining nonrotative because of the pin 58. The bearing collarfild maintains concentricity of the outer end of the piston shank As thus assemtate nor move axially with reference to the main torque tube '56; the cylinder d8 may move axially but may not rotate with reference to the main torque tube 46; and the piston st, its shank 52 and bearing collar 5 may not move axially but may rotate with reference to the main torque tube 46.

In readying the device for operation, the main a torque tube 55 with the sleeve 62 inserted and fastened by rivets i8 is slipped through the loops Men the trailing end of the target 3%, then the target Ellis rolled around the outside of the tube 46. The tube 5% with the target rolled around it,is then inserted endwise into the drag elementid and'within the bounds of the guide strips 28, several inches of the leading end of the target being unrolled and passed endwise through the slot 25 when the tube it is being inserted endwise into the drag element The spreader bar 3% is now attached to the leading end of the target, the bridle lines being permanently secured to the spreader bar by loops 32, Fig. 10. From the spreader bar 3d, the bridle lines converge and are connected at as to the trailing end of the tow cable All.

ends joined at 38 to the trailing end of the tow cable 46, and diverge and are joined in spaced relation to the spreader bar 34. The leading end or the target, 36 is joined to the spreader bar 34 by loops 32.

Within the drag element 2:) andwithin the bounds of the guide strip '28, the target 30 is fully rolled except for several inches which protrude as at 18 from the slot 23 of the drag element 2%].

The device may now be launched by paying out tow cable M} from the reel M, the hydraulic system in the meantime operating automatically to control the unfurling of the target 38.

Fig. 2 shows the device with the tow cable extended and the target partly unfurled.

Having described an embodiment of my invention, I claim:

1. A nonrigid tow targetcomprising a rotatable rigid torque tube, a flexible fabric target closely rolled over the outside of said rigid torque tube, and resistance means including a cylinder closed at one end and a dash pot piston therein within said tube responsive to unrolling of said target from off the outside of said tube to move axially relatively toward each other to provide resistance to rotation of said tube to retard unrolling or" said target. a

2. A tow target comprising an elongated drag element, a torque tube positioned longitudinally in said'drag element and rotatable with reference thereto, a tow target wrapped snugly around said torque tube and adaptedto be unrolled' to rotate said torque tube, rotation retarding means within said torque tube including an internally threaded. cylinder and an externally threaded piston therein responsive to rotation of said torquetube to move relatively axially toward each other, anda resisting means within the cylinder opposing said axial movement.

3. A tow target comprising a drag element, a torque tube positioned vertically in said drag element and rotatable therein with reference thereto, a flexible fabric target secured to said torque tube and closely rolled around said torque tube whereby unrolling said target rotates said torque tube with reference to said drag element, and resisting means within said torque tube movable axially with respect thereto by unrolling of said target to rotate said torque tube.

,4. A tow target comprising a drag element, a

V torque tube positioned vertically in said drag 'unroll said target rotates said torque tube, a

sleeve within said torque. tube constructed to rotate therewith, a cylinder within said sleeve. Io-

tatable thereby and axially movable therein, a piston in said torque tube fixed against rotation and axial movement with reference to said drag element, and means responsive to rotation of said torque tube to move said cylinder axially with respect to said piston.

5. A tow target comprising a drag element, a torque tube positioned vertically in said drag element and rotatable therein with respect thereto, a flexible fabric target secured to said torque tube and closely rolled therearound, whereby pulling on the outer end of said fabric target to unroll said target rotates said torque tube, a sleeve within said torque tube constructed to rotate therewith and fixed against axial movement therein, an-internally threaded cylinder within said sleeve and rotatable thereby and axially movable therein, an externally threaded piston within said internally threaded cylinder fixed against rotation and axial movement with respect to said drag element, and means to release said piston to permit rotation thereof.

6. A tow target comprising an elongated hollow drag element slotted throughout its length, a torque tube of substantially less outside diameter than the inside diameter of said drag element positioned longitudinally in said drag element, guide strips carried by said drag element of substantially greater inside diameter than the outside diameter of said torque tube and slotted to correspond to said drag element, a flexible fabric target having one end secured to said torque tube and closely rolled therearound and the other end extended outwardly through the slots of the drag element and of the guide strips whereby pulling on the extending end of said target rotates said torque tube, a sleeve within said torque tube adapted to rotate therewith and fixed against axial movement therein, an internally threaded cylinder within said sleeve rotatable thereby and axially movable therein, and an externally threaded piston threadably received in said internally threaded cylinder and fixed against rotation and axial movement during rotation and axial movement of said cylinder during rotation of said torque tube by unrolling of said flexible fabric target from the said torque tube.

7. A tow target comprising an elongated hollow drag element of square transverse section with one corner slotted throughout its length,

guide strips of V-shaped contour in one corner of the drag element with the sides of the V lying along the sides of the drag element and the point of the v slotted and in alignment with the slot of the drag element, a torque tube extending longitudinally within the drag element and within the confines of the guide strips, a flexible fabric target having one end secured to said torque tube and closely rolled therearound and the other end extended outwardly through the said slots whereby pulling on the extending end of said target first pulls said target against the sides of the I then rotates the said target against the frictional resistance between the rolled target and the sides of the V, whereby the unrolling of the target is retarded.

8. A tow target comprising an elongated hollow framework of square transverse section with one corner slotted throughout its length, guide strips of V-shaped contour in one corner of the drag element with the sides of the V lying along the sides of the drag element, and the point of the V slotted and in alignment with the slot of the drag element, a torque tube extending longitudinally within the drag element and within the confines of the guide strips, a flexible fabric target having one end secured to said torque tube and closely rolled therearound, and the other end extended outwardly through the said slots, whereby pulling on the extended end of said target first pulls said target against the sides of the V, then rotates the said target against the frictional resistance between the rolled target and the sides of the V whereby the unrolling of the target is retarded, and hydraulic leakage means within the torque tube operative by rotation of the torque tube to control said hydraulic leakage means to further retard unrolling of said target.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 700,698 Mountford May 20, 1902 1 1,752,010 Lamkey Mar. 25, 1930 1,794,828 Bleriot Mar. 3, 1931 2,183,540 Campbell Dec. 19, 1939 2,523,738 Trimbach Sept, 26, 1950 2,538,719 Shee Jan. 16, 1951

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