US3456909A - Canopy landing structure - Google Patents

Description

July 22, 1969 w. H. WAINWRIGHT CANOPY LANDNG STRUCTURE s sheets-sheet 1 Filed rpril 4, 1967 INVENTOR. WILLIAM H. WAINWRIGHT FIGZ July 22, 1969 w. H. wAnNwRlGH-r 3,456,909

CANOPY LANDNG STRUCTURE Filed April 4,1967 v 5 sheets-sheet 2' INVENTOR. WILLIAM H. WAINWRIGHT July 22, 1969 w. H. wAlNwRlGHT 3,456,909

CANOPY LANDING STRUCTURE Filed April 4, 1967 3 SheetS-Sheet- INVENTOR. WILLIAM H. WAI NWRIGHT TM mum United States Patent Oflce 3,456,909 CANOPY LANDING STRUCTURE William H. Wainwright, 61 Highland St., Cambridge, Mass. 02138 Filed Apr. 4, 1967, Ser. No. 628,476 Int. Cl. B641 00 U.S. Cl. 244-114 9 Claims ABSTRACT OF THE DISCLOSURE A landing structure for airborne vehicles, personnel and material which can lbe used on the natural canopy formed by, tree tops, vines, bushes and similar ground cover. One or more tension nets are spread on top of the canopy to gather enough vertical reaction from the underlying ground cover to Support the required load. A rigid, skeletal space frame is positioned on the load receiving portion of the tension nets to provide a stable, substantially horizontal support for a landing platform that is secured to the frame. The platform can be a wire mesh net for landing personnel and small equipment or a solid platform to permit the landing of helicopters and heavy materiel.

Background of the invention This invention relates to landing structures for airborne vehicles, personnel and materiel and, more particularly, to a landing structure which can be used in areas where the natural ground cover precludes an initial ground landing by the airborne vehicle.

In many parts of the World, the natural ground cover is suiciently dense or otherwise structured to prevent helicopters from landing on the ground. Typical examples of such areas are found in the rain forests [and jungles of the equatorial zone and the deciduous forests of the temperate zones. It is often desirable in such areas to olf load and on load personnel and equipment either for military or commercial purposes. In addition, a temporary landing site is generally needed during the time required for the olf-loaded ground personnel to clear a suflicient land area to provide a permanent ground level landing site.

It is accordingly a general object of the present invention to provide a landing structure that can be airlifted to a remote landing site and then placed upon the local ground cover canopy to form a landing structure for airborne vehicles, personnel and materiel.

'It is a specific object of the present invention to provide a canopy landing structure that will support relatively heavy loads with a minimum number of structural components.

It is another object of the present invention to provide an extremely lightweight landing `structure that can be assembled into a few major components at a convenient location and then airlifted to the desired landing site where the components can be put together by a small number of personnel.

In the accomplishment of these objects, I employ one or more resilient, locally deformable, tension nets that can be airlifted to the la-nding site and then deployed on top of the ground cover canopy to form a central load receiving area and two or more opposed load distributing areas. If desired, a separate space frame having a suitable platform can be placed on the load receiving portion of the net or nets to provide a stable platform for helicopters, personnel and equipment.

Patented July 22, 1969 selected for purposes of illustration, and shown in the accompanying drawings.

Brief description of the several Views of the drawings FIGURE 1 is a view in perspective showing the deployment of two airlifted tension nets of the present invention on a tree top canopy and a space frame platform about to be deposited on the crossed nets;

FIGURE 2 is an enlarged plan view of a portion of one of the tension nets shown in FIGURE 1;

FIGURE 3 is a plan view of the space frame shown in FIGURE 1;

FIGURE 4 is a side elevation of the space frame shown in FIGURE 3; and

FIGURE 5 is a plan view of an alternate embodiment of the present invention utilizing a star shaped tension net and showing a helicopter resting on the space frame platform.

Description of the preferred embodiments Turning now to the drawings and particularly to FIG- URE 1 thereof, there is shown in perspective view, a representative example of the deployment of the landing structure of the present invention, indicated generally by the reference numeral 10, on a ground cover canopy 12 by threeairborne helicopters 14, 16 and 18. As shown in FIGURE 1, thefirst helicopter 14 has already d-eployed one tension net 20 on top of the ground cover canopy 12. The second helicopter 16 is shown in the process of laying down anothertension net 22 from a reeltype net carrier 24. After the twotension nets 20 and 22 have been laid down in a crossed configuration, the third helicopter 18 deposits a skeletal, rigid, spaced frame and landing platform, indicated generally as 26, on the crossed portion of the nets. Thereafter, men are landed on the nets to position and secure the spaceframe landing platform 26 for subsequent use by the helicopters as a helipad.

Having briefly described a typical deployment of the canopy landing structure 10, it will now be helpful to examine in detail the major structural components thereof. In its basic form, the present invention comprises a single tension net, for example, net 20 shown generally in FIGURE l and in greater detail in FIGURE 2. The purpose of the net is threefold: first to gather enough vertical reaction and horizontal support from the tree tops or canopy to both support and stabilize the required load including thespace frame platform 26, if one is employed; second, to provide an extension of the platform which will suppress the adjacent tree tops and provide clearance for helicopter rotors; and, third, to provide a safety net for personnel.

Preferably, the net is fabricated from a wire'rope 28 that is joined at intersections by suitable clamps orswaging sleeves 30 as shown in FIGURE 2.Wire clips 32 are used to secure the wire ropes whenever the ropes do not cross, as for example, along the outer longitudinal ropes which form the sides of the tension net. For the net dimensions and design loads hereinafter described, it had been found that a wire rope of 7 x 19 galvanized aircord type; U.S. military specifications: cable steel (carbon) flexible, preformed MIL-W-15llA is satisfactory.

The particular grid pattern of the net with 90 intersections has been found to provide a stronger and more 3 easily deployed net than the more commonly used fabrication technique of joining wires parallel to each other. This type of construction produces a resilient and locally deformable net that will readily conform to the complex topological features of the ground cover canopy 12. Since the net 20 is under tension in its operative position, it can be described from a functional standpoint as having a load receiving portion and at least two load distributing portions, identified by the reference numerals 20a and 20h-20c, respectively, in FIGURES 1 and 2.

Looking at these figures, it can be seen that the central load receiving portion 20a has much liner wire mesh than the end sections or load distributing portions 2Gb and 20c. For a design load of 10,000 lbs., the tension net 20 would typically have exterior dimensions of 250 ft. by -20 ft. Given these dimensions, each load distributing portion is approximately 90 feet long and the center section or load receiving portion is 60 ft. long. The grid pattern within each of the end load distributing portions has a nominal dimension of 2.5 ft. x 2.5 ft. square while the grid pattern within the central load receiving portion has a nominal dimension of 0.5 ft. x 0.5 ft. square thus producing a 5:1 size ratio.

It should be understood that the above dimensions are merely illustrative of a particular configuration and design load and, therefore, should not be construed as limiting the scope of the present invention. Furthermore, although the use of different mesh dimensions for the load receiving portion and the load distributing portions is preferred, it is not absolutely essential since a single mesh dimension can be employed for the entire net. It will therefore be apparent to those skilled in the art that the basic concept herein described is a canopy landing structure comprising at least one resilient, locally deformable tension net having a load receiving portion and a plurality of load distributing portions.

In order to facilitate the deployment of the tension net and maintain the net in a spread condition, a number of telescoping,transverse spreaders 34 are provided in each portion of the net. Thespreaders 34 are made to telescope so that they can be used with nets of varying widths thereby greatly reducing the number of individual components which must be stockpiled and moved through the supply pipeline.

Looking at FIGURE 2, the distal end of the tension net is provided with agrapnel 36 which engages the tree tops or other ground cover and helps to uncoil the net from thereel mechanism 24 as shown in FIG- URE l. Of course, other systems, such as an accordion folding of the net or an explosive charge can be used to assist in deploying the tension net over the ground cover.

One of the advantages of the present invention is its inherent flexibility to accommodate various design loads and stability requirements. For example, in its simplest form, a single small net can be used for disembarking troops. If slightly greater loads are to be handled, additional nets can be added with the load receiving portions of each net assembled in superposed relation as shown in FIGURE l. The next step up in strength and stability is the addition of a simple, single layer, rigid platform which provides a stable base for unloading equipment, mounting Winches, etc. This platform has not been depicted by itself in the drawings because it forms an integral part of the next step up in stability and strength. At this point, an additional surface platform is added with leveling legs using the rst platform as a base. Collectively, this structure defines the previously mentioned rigid, skeletal space frame andplatform 26 shown generally in FIGURE l and in greater detail in the plan and side elevational views of FIGURES 3 and 4 respectively.

Referring to FIGS. 3 and 4, the space frame andplatform 26 comprises a triangular base formed from threetubular members 38 and a hexagonal platform support constructed from sixtubular members 40 that are secured together bykeystone fasteners 42. The triangular base members and hexagonal platform support members are held in parallel, planar relation by a plurality of connectingmembers 44 which are secured at one end to thekeystone fasteners 42 and at the other end bytie plates 46 mounted on three vertical tubular supports 48. Threadably engaged within eachtubular support 48 is a levelingleg 50 that terminates in a pivotally mountedleveling pad 52. Levelingpad 52 has a generally inverted trough-shape with serrated edges to grip the tension net when the space frame is lowered onto the net by helicopter 18 as shown in FIG. 1.

The skeletal, hexogonal frame formed bymembers 40 provides a support for a suitable platform, such as, a relativene mesh net 54. The net 54 can be fabricated from wire or other materials including ordinary hemp rope and nylon or other synthetic materials. Alternatively, a solid continuous platform, formed for example from aluminum skinned sandwich panels, can be mounted on the hexagonal support to provide a landing platform for helicopters and a loading platform for heavy equipment.

Although the description of the canopy landing structure of the present invention has so far been limited to nets having a generally rectangular shape, it should be understood that the invention is not restricted to such configuration. For example, an alternate embodiment of the present invention is illustrated in FIGURE 5 wherein atension net 56 has a generally star-shaped configuration. In this embodiment, the centralload receiving portion 56a comprises a circular area while the load distributing portions 56b are formed generally by the six points of the stan Having described in detail the preferred embodiment of the present invention, it will now be apparent to those skilled in the art that numerous modifications can be made without departing from the scope of the invention.

For example, a single platform layer, pneumatic cushion, or other structure can be positioned on the load receiving portion of the net in place of the space frame. Additionally, it should be understood that in certain topological situations where the load receiving portion is positioned on top of a tree, the load distributing portions of the net may function substantially as guys for the central load receiving portion.

What I claim is:

1. A canopy landing structure comprising: a plurality of resilient, locally deformable tension nets each having a load receiving portion and a plurality of load distributing portions, said nets assembled with only the load receiving portions thereof in superposed relation.

2. A canopy landing structure comprising: at least one resilient, locally deformable tension net having a load receiving portion and a plurality of load distributing portions, said load receiving portion having a `liner mesh than said load distributing portions.

3. A canopy landing structure comprising: at least one resilient, locally deformable tension net having a substantially star-shaped configuration with the center of the star-shaped net forming the load receiving portion and the star points forming the load distributing portions.

4. A canopy landing structure comprising: at least one resilient, locally deformable tension net having a load receiving portion and a plurality of load distributing portions; and, a rigid, space frame positioned on said tension net in the load receiving portion thereof.

5. The structure of claim 4 further characterized by said space frame having a triangular base, a hexagonal platform support and interconnecting means for maintaining said base and platform support in planar, parallel relation.

6. The structure of claim 5 further characterized by a platform secured to said hexagonal platform support.

7. The structure of claim 6 wherein said platform comprises a net.

5 6 `8. The structure of claim 6 wherein said platform com- FOREIGN PATENTS 475,066 10/1952 Italy.

prises a continuous structure.

9. The structure of claim 4 further characterized by means for leveling said space frame.

OTHER REFERENCES References Cited 5 Science News, Helicopter Unloads on Treetops, 891250,

. 6, UNITED STATES PATENTS Apr 9 196 P 250mm "n 9/ 1957 Hawkins et al, 244-114 MILTON BUCHLER, Primary Examiner 6/1962 Grundy 244114 PAUL E. SAUBERER A 't t E amine 7/1963 Oestrich 244-114 10 Ss an X r 9/1964 Laufer 244-114

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