Abstract:
An aerial delivery system includes at least one container mounted on a platform, an impact attenuator initially interposed between the container and the platform, an activation tether arranged to cause contents of the container to disperse, and rigging material attached to the impact attenuator, the platform and the activation tether and configured to rotate the platform to face upward and the impact attenuator to face downward during aerial delivery.

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The invention described herein may be manufactured and used by or for the U.S. Government for governmental purposes without the payment of any royalties thereon or therefor. 
    
    
     FIELD 
     The disclosed embodiments relate in general to an aerial delivery system, and more particularly to providing aerial delivery while mitigating a risk of injury. 
     BACKGROUND 
     Natural disasters often result in a lack of food or clean water for the first 48-72 hours after the disaster occurs as a result of infrastructure damage, for example, power plants, water treatment plants, roads, ports and runways. Airdrops of humanitarian aid supplies such as medical supplies, food and clothing provide needed relief in these situations. In a related area, forestry fire fighters are generally resupplied with food and water by aerial delivery of multiple 50 pound bundles. Various military ground operations may require resupply of ammunition, clothing and rations through aerial delivery, and both military and commercial organizations may seek to provide information to a population through aerial delivery. 
     Present airdrop capabilities, in particular, humanitarian food and water drops, suffer from drawbacks including a lack of ability to deliver water and a large injury risk posed by delivery mechanisms including containers, skid boards and large food items, for example, Meals Ready to Eat (MREs) or Humanitarian Daily Rations (HDRs). The U.S. and British armies and private industry have used impact attenuators in several forms for aerial delivery. For example, external struts comprised of inner and outer cylinders that force hydraulic fluid through an orifice to dampen impact have been used on spacecraft capsules as well as on aircraft main landing gear. These systems provide great control over the force/time curve, however they are expensive, complicated, and beyond the expertise of the average rigger. Airbags have also been used in several military applications. The British have used a specially designed platform, the Medium Stress Platform (MSP), with recesses to house deflated airbags for cargo airdrop. Upon exit from the aircraft, the airbags inflate and attenuate the load during impact. This system utilizes a fixed venting area, resulting in a peaked force/time curve, where a “rectangular” profile is desired. The rectangular force/time curve can be obtained with airbags using variable venting areas, adding to the cost and complexity of the system. As much of the stroke of the airbag is used to build the pressure, the system is often excessively large, leading to possible hazards on the ground, including re-inflation of the airbag and payload roll over. In addition, the aircraft-platform interface has to be modified to accept these platforms. 
     Present delivery systems also suffer from clumping, where items have a tendency to clump together and fail to disperse over the drop zone. Furthermore, items that clump together generally fall faster and experience a much harder impact, reducing their survivability and usefulness after landing and creating a danger for those on the ground in the drop zone. 
     It would be advantageous to utilize an airdrop system that overcomes these and other problems and safely disperses various items directly over a population. 
     SUMMARY 
     The disclosed embodiments are directed to an aerial delivery system including at least one container mounted on a platform, an impact attenuator initially interposed between the container and the platform, an activation tether arranged to cause contents of the container to disperse, and rigging material attached to the impact attenuator, the platform and the activation tether and configured to rotate the platform to face upward and the impact attenuator to face downward during aerial delivery. 
     The disclosed embodiments are also directed an aerial delivery system having a plurality of containers mounted on a platform, an impact attenuator initially interposed between the containers and the platform, a rigging arrangement passing through the impact attenuator and the platform, the rigging arrangement including an activation tether arranged to cause contents of the containers to disperse, and a suspension point attached to an end of the activation tether, the rigging arrangement configured to rotate the platform to face upward and the impact attenuator to face downward during aerial delivery. 
     These and other aspects and advantages of the exemplary embodiments will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. Additional aspects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. Moreover, the aspects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate presently preferred embodiments of the present disclosure, and together with the general description given above and the detailed description given below, serve to explain the principles of the present disclosure. As shown throughout the drawings, like reference numerals designate like or corresponding parts. 
         FIG. 1  shows a diagram of an initial configuration of an aerial delivery system incorporating aspects of the present disclosure; 
         FIG. 2  shows an exemplary platform of an aerial delivery system incorporating aspects of the present disclosure; 
         FIG. 3  shows an exemplary assembly of the platform and an impact attenuator incorporating aspects of the present disclosure; 
         FIGS. 4 and 5  show an arrangement of rigging material of an aerial delivery system incorporating aspects of the present disclosure; 
         FIG. 6  shows an activation tether incorporating aspects of the present disclosure; 
         FIG. 7  shows an arrangement of a platform, an impact attenuator, and rigging material incorporating aspects of the present disclosure; 
         FIG. 8A  shows an arrangement of an enclosure net and containers positioned on an impact attenuator incorporating aspects of the present disclosure; 
         FIG. 8B  shows an arrangement of a lanyard attached to containers and to an attachment point of an activation tether according to the present disclosure; 
         FIG. 9  shows a diagram of an aerial delivery system incorporating aspects of the present disclosure; 
         FIG. 10  shows an exemplary deployment of an aerial delivery system incorporating aspects of the present disclosure; 
         FIG. 11  shows the results of the operation of a release mechanism according to aspects of the present disclosure; 
         FIG. 12  shows delivery items being dispersed according to aspects of the present disclosure; 
         FIG. 13  shows components of the delivery system being retained according to aspects of the present disclosure; and 
         FIG. 14  shows an exemplary result of deployment of the system after touch down according to aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , one embodiment of an aerial delivery system  100  incorporating aspects of the disclosed embodiments is illustrated. The aspects of the disclosed embodiments are generally directed to an aerial delivery system that allows for dispersion of items directly above an active population while mitigating the risk of injury. The disclosed embodiments at least provide for releasing items in tiers for improved dispersion and to avoid clumping, reconfiguration of impact attenuator material after deployment, and retention of all delivery components to avoid injury to the active population. 
       FIG. 1  shows a schematic diagram of an initial configuration of an aerial delivery system  100  according to the disclosed embodiments. Delivery system  100  includes a parachute  102 , one or more containers  104 , a platform  106  and an impact attenuator  108 . The impact attenuator  108  is initially positioned between the containers  104  and the platform  106 . An enclosure net  110 , in this example constructed of rigging materials, operates to hold the components of the delivery system together. The delivery system  100  may also include a release mechanism  112  and an activation tether described below. In at least one embodiment, the initial configuration is compatible with various aircraft cargo handling arrangements, for example, powered cargo handling equipment, forklifts, conveyors, rails and rollers in the aircraft cargo bay, where the initial configuration construction, materials, and dimensions are generally compatible with various aircraft cargo systems. 
       FIG. 2  shows an exemplary platform  106 . The platform may be made of a rigid material, for example, plywood, and may be provided with holes, placed in at least one aspect, so as to avoid interference with any cargo handling arrangement or other interface with the platform  106 . In at least one embodiment, the platform  106  has four holes, one located in each of four quadrants of the platform  106 . Two holes  202  may be placed adjacent one edge  204  of the platform and two holes  206  may be placed adjacent an opposite edge  208  of the platform. 
       FIG. 3  shows an exemplary assembly of the platform  106  and impact attenuator  108 . The platform  106  and impact attenuator  108  may be fastened together, for example, by gluing or any other suitable fastening technique. In at least one embodiment, the impact attenuator  108  may include different materials in a layered structure, for example, an inner honey comb layer  310  and an outer high density foam layer  312 . It should be noted that the impact attenuator may be constructed of any material or number of materials suitable for diminishing impact. The impact attenuator  108  may be provided with holes  302 ,  306  corresponding to the holes  202 ,  206  in the platform  106 . A first piece of rigging material  304  may be laced through the holes  302  in the impact attenuator  108  and the corresponding holes  202  in the platform adjacent edge  204  of the platform  106 . A second piece of rigging material  308  may be laced through the holes  306  in the impact attenuator  108  and the corresponding holes  206  in the platform adjacent edge  208  of the platform  106 . 
     As shown in  FIG. 4 , each piece of rigging material  304 ,  308  may be laced so that ends  404  of the first piece of rigging material  304 , and ends  408  of the second piece of rigging material  308 , extend from the impact attenuator  108  and exit through a side of the platform  310  facing away from the impact attenuator  108 . As shown in  FIG. 5 , ends  404  and  408  are secured together to form a rigging suspension point  510 . 
       FIG. 6  shows an activation tether  600  to be connected at one end to the suspension point  510 . The activation tether  600  includes a suspension point attachment  602 , a plurality of spaced apart tiered attachment points  604 , a cut knife  606 , and an upper attachment point  608 . 
     As shown in  FIG. 7 , the platform  106  and impact attenuator  108  are inverted and the rigging material  304 ,  308  is secured in place, allowing the platform to freely interface with various aircraft cargo handling arrangements, for example, powered cargo handling equipment, forklifts, conveyors, rails and rollers in the aircraft cargo bay, and any other device for transporting the aerial delivery system  100 . The rigging material  304 ,  308  and suspension point  510  may then be draped over the impact attenuator and the suspension point  510  may be attached to the activation tether  600 . 
     As shown in  FIG. 8A , enclosure net  110  is placed over the impact attenuator  108  with at least the activation tether  600  extending through and operating to retain the enclosure net  110 . In some embodiments, the suspension point  510  may also extend through the enclosure net  110 . Additional rigging (shown in  FIG. 1 ) may secure the enclosure net  110  to the impact attenuator  108  or the platform  106 . The containers  104  are stacked on the impact attenuator over the enclosure net  110  in alternating tiers with each tier oriented lengthwise perpendicular to the next. The containers  104  may be filled before assembling the aerial delivery system  100  or may be filled as each tier is assembled. In at least one embodiment, lanyards  810  are attached to adjacent containers  104  in each tier and then to one of the tiered attachment points  604  of the activation tether  600 , as shown in  FIG. 8B . While the lanyards  810  are shown attached to the bottom of the containers  104 , it should be understood that the lanyards may be attached to any portion of the containers so long as the contents of the containers are effectively emptied from the containers during deployment. 
       FIG. 9  shows a schematic diagram of at least one embodiment of the final assembly  900  of the aerial delivery system  100 , for example, for use in a High Altitude Low Opening (HALO) deployment. Extensions  910  of the enclosure net  110  are joined together to form an enclosure suspension point  915  which is fastened to release mechanism  112  which is fastened to a parachute suspension point  920  for parachute  102 . In some embodiments, release mechanism  112  may be a three ring release mechanism, a four ring release mechanism, or any other mechanism suitable for releasing a connection between the enclosure suspension point  915  and the parachute suspension point  920 . The release mechanism  112  operates to allow the enclosure suspension point  915  and the parachute suspension point  920  to separate according to a specified condition, for example, at a specified altitude or after a specified time period. In at least one embodiment, the release mechanism may include a wireless activation device which may be activated by one or more of altitude, timing, or a wireless signal. The upper attachment point  608  of activation tether  600  is also attached to the parachute suspension point  920 . In at least one exemplary embodiment, the cut knife  606  of the activation tether  600  is positioned to cut the extensions  910  of the enclosure net  110  upon release by the release mechanism  112  to provide a substantially uniform dispersion of the contents of containers  104 . In another exemplary embodiment of the final assembly  900 , for example, for use in direct deployment, the release mechanism may be eliminated with only the upper attachment point  608  of activation tether  600  attached to the parachute suspension point  920 . The parachute may be, for example, a 15′ ring slot parachute, a 26′ high velocity parachute, or any parachute having a canopy shape, size, configuration or suspension suitable for the embodiments described herein. 
     In a HALO deployment, the parachute  102  inflates upon exit from an aircraft and descends with the enclosure net  110  and containers  104  as shown in  FIG. 10 . Upon reaching a prescribed altitude or exceeding a prescribed time duration, the release mechanism  112  releases the enclosure net  110  and containers from the parachute  102  as shown in  FIG. 11 . As the separation distance increases, the still attached activation tether  600  extends and the lanyards  810  attached to each tier of containers  104  cause the containers  104  to change orientation, for example to invert, and their contents  1205  are dispersed tier by tier as shown in  FIG. 12 . Advantageously, the tiered release reduces clumping of the contents and provides for improved dispersion over the drop area. All the components of the delivery system  100 , including the parachute  102 , containers  104 , enclosure net  110 , platform  106  and impact attenuator  108  remain attached to activation tether  600  and lanyards  810  as shown in  FIG. 13 . As the activation tether  600  extends, the suspension point attachment  602  of the activation tether  600  pulls on the rigging suspension point  510  ( FIG. 5 ), causing the platform  106  and impact attenuator  108  to rotate and change orientation with the platform  106  facing up and the impact attenuator  108  facing downward before touching down. The down facing impact attenuator operates to reduce or eliminate injury to ground personnel from the delivery system during touch down. 
     In a direct deployment, the enclosure net  110  and containers  104  separate from the parachute  102  upon exiting the aircraft. Similar to the embodiment above, as the separation distance increases, the still attached activation tether  600  extends and the lanyards  810  attached to each tier of containers  104  cause the containers  104  to change orientation and their contents  1205  are dispersed tier by tier. In direct deployment, the containers  104  also remain attached to the lanyards  810  and activation tether  600 . Similar to the embodiment above, as the activation tether  600  extends, the suspension point attachment  602  of the activation tether  600  pulls on the rigging suspension point  510  ( FIG. 5 ), causing the platform  106  and impact attenuator  108  to rotate and change orientation with the platform  106  facing up and the impact attenuator  108  facing downward before touching down. 
       FIG. 14  shows an exemplary result of deployment of the system after touch down, with the platform  106  facing upward, the impact attenuator  108  facing down, the enclosure net  110  and activation tether  600  still attached. The parachute and containers (not shown in this Figure) remain attached to the activation tether and the lanyards. 
     The disclosed aerial delivery system provides improved content dispersion by releasing the content material in tiers, operates to reconfigure a support platform during flight so that an impact attenuator faces downward to protect ground personnel from a support platform or other components of the aerial delivery system, and retains all delivery system components together to minimize injury risk and to facilitate recovery of delivery system components if desired. 
     Thus, while there have been shown, described and pointed out, fundamental novel features of the invention as applied to the exemplary embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of devices and methods illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. Moreover, it is expressly intended that all combinations of those elements and/or method steps, which perform substantially the same function in substantially the same way to achieve the same results, are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.