Abstract:
An airborne mobile platform may have a wing having a length and a chord wise dimension, and a plurality of elongated structural components extending span-wise along the length of the wing. The elongated structural components may each have a localized hinge area. A device may be used for manipulating the elongated structural component to position the localized hinge area to selectively change a hinge line of the wing in response to an airflow over the wing.

Description:
FIELD 
     The present disclosure generally relates to airborne mobile platforms, and more particularly to controlling the cord-wise stiffness of the wings on a mobile platform in a manner that allows the natural aerodynamic bending forces experienced by the wings during flight to twist the wings as needed in a controlled fashion, to assist in controlling flight of the mobile platform. 
     BACKGROUND 
     Aircraft designers are tasked with developing efficient technologies for controlling an aircraft flight path. In the earliest years of aviation, the Wright brothers used mechanical wires to twist the wing for aircraft roll control. Traditionally, aircraft have used moveable flap-like control surfaces (ailerons) to roll the aircraft or adjust the aircraft attitude. Recently, aircraft designers have started to devise ways of controlling and using aircraft aero-elastic wing twisting for roll control. This has involved using such components as a torque tube disposed in each wing, and running substantially the full span-wise length of the wings, to assist in twisting the wings to help provide flight control maneuvering for the aircraft. Such systems, however, have often required large, heavy and expensive motors to provide the necessary twisting force to the torque tube. 
     Accordingly, it would be highly advantageous to provide some means for controllably twisting a wing to assist in controlling flight of an aircraft, but without the large, heavy and expensive wing twisting structures that have previously been attempted. 
     SUMMARY 
     The present disclosure relates to an airborne mobile platform that may comprise a wing having a length and a chord wise dimension, and a plurality of elongated structural components extending span-wise along the length of the wing. Each elongated structural component may have a localized hinge area. A device may be used for manipulating the elongated structural components to position the localized hinge area to selectively change a hinge line of the wing in response to an airflow over the wing. 
     In another aspect the present disclosure may comprise a wing, where the wing includes a plurality of elongated structural components extending span-wise along the wing. The elongated structural components may each have a localized hinge area. A subsystem may be used for manipulating the elongated structural components to selectively position the localized hinge area to controllably position a hinge line of the wing, and without imparting a twisting force to the wing. 
     In still another aspect the present disclosure may comprise a method for controllably positioning a hinge line on a wing of a mobile platform that includes providing a plurality of structural components extending span-wise within the wing. A localized hinge area may be formed in each structural component. Each structural component may be controlled to position the localized hinge area within the wing so as to controllably vary the position of a hinge line of the wing. 
     Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating various embodiments, are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of an aircraft with neutral, positive and negative hinge lines illustrated by dashed lines on one of the wings, and an apparatus for twisting the wing illustrated by dashed lines on the other wing; 
         FIG. 2  is a simplified diagrammatic view of one of the wings shown in  FIG. 1 , with the wing shown in phantom, and illustrating a plurality of structural components within the wing for controllably forming the hinge line along the wing; 
         FIG. 2A  is a simplified diagrammatic plan view of the wing of  FIG. 2  illustrating the orientation of the hinge line formed when the structural components are positioned as shown in  FIG. 2 ; 
         FIG. 2B  is an end view of the wing of  FIG. 2A  illustrating the upward twisting of the leading edge of the wing at the wing tip as a result of the orientation of the hinge line in  FIG. 2A ; 
         FIG. 2C  is a perspective view of one of the structural components shown in  FIG. 2  better illustrating the angular orientation of the cutouts formed on the structural component. 
         FIG. 3  is a simplified diagrammatic plan view of the wing of  FIG. 2  but with the structural components having been rotated 90 degrees; 
         FIG. 3A  is a simplified plan view of the wing of  FIG. 3  illustrating the orientation of the hinge line formed by the positioning of the cutouts in the structural components shown in  FIG. 3 ; 
         FIG. 3B  is an end view of the wing of  FIG. 3A  illustrating the downward twisting at the tip of the wing as a result of the orientation of the hinge line shown in  FIG. 3A ; 
         FIG. 4  is a simplified, diagrammatic perspective view of a wing shown in phantom, with internally mounted structural components, in which the structural components each have a cruciform shape when viewed cord-wise, with cutout sections selectively arranged along various panels of each of the cruciform shaped structural components; 
         FIG. 4A  is a plan view of the wing of  FIG. 4  illustrating the orientation of the hinge line formed when the cutouts are disposed as illustrated in  FIG. 4 ; 
         FIG. 5  is a simplified, diagrammatic perspective view of the wing of  FIG. 4 , but with the structural components having been rotated 90°; 
         FIG. 5A  is a plan view of the wing of  FIG. 5  illustrating the orientation of the hinge line formed by the positioning of the cutouts in the cruciform shaped structural components of  FIG. 5 ; 
         FIG. 6  is a simplified, diagrammatic plan view of a wing incorporating telescoping tubular structural components; 
         FIG. 6A  is a simplified perspective view of a portion of one of the telescoping tubular structural components shown in  FIG. 6 ; and 
         FIG. 7  is a perspective view of a structural component that makes use of a spiral cut-out to form a localized hinge area. 
     
    
    
     DETAILED DESCRIPTION 
     The following description of the various preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the present disclosure, its application, or uses. 
     Referring to  FIG. 1 , there is shown an exemplary airborne mobile platform, in this example an aircraft  10 , including a pair of wings  12   a  and  12   b , and a body or fuselage portion  14 . While an aircraft is illustrated, it will be appreciated that the present disclosure is applicable to any airborne mobile platform, manned or unmanned, that makes use of wings to control its flight. 
     Wing  12   b  of the aircraft  10  includes a dashed line  16  that illustrates a “neutral” sweep hinge line. The neutral sweep hinge line can be viewed as representing the natural bending line of the wing as the wing experiences aerodynamic forces during flight. Dashed line  18  represents a “pseudo” wing hinge orientated to provide a negative sweep hinge line. Dashed line  20  represents another pseudo hinge line that is orientated to provide a positive sweep hinge line. Wing  12   a  is illustrated with a structural component or assembly  22  represented by dashed lines disposed inside the wing. It will be appreciated, however, that wing  12   b  similarly includes structural component  22 , but the dashed lines indicating its presence have been deleted for clarity. Thus, each of the wings  12   a  and  12   b  include structural component  22 , and each are preferably independently controlled by a suitable flight control computer or other subsystem carried on the aircraft  10 . Each wing ( 12   a  and  12   b ) includes hinge sweeps  16 ,  18  and  20  as well. 
     In brief, the structural components  22  in the wings  12   a  and  12   b  serve to modify the orientation of the hinge line in each wing to provide either a negative hinge sweep, as indicated by dashed line  18 , or a positive hinge sweep, as indicated by dashed line  20 , or possibly any intermediate degree of hinge sweep between hinge lines  18  and  20 . Controlling the orientation of the hinge line in each wing  12   a  and  12   b  allows the natural aerodynamic forces experienced by the wings during flight to assist in twisting the wings as needed to achieve the desired flight control characteristics. For example, during landing operations, a negative hinge sweep is desirable, while at cruise altitudes a neutral hinge sweep is most desirable. A particular advantage of the system and method described herein is that since the natural aerodynamic forces experienced by the wings provide a significant degree of the force needed to twist the wings  12   a ,  12   b , that heavy, large and expensive motors and other like devices, that would otherwise be needed to twist the wings, are not needed with the present system and method. 
     Referring to  FIGS. 2-2C , one embodiment of the structural component  22  is illustrated in wing  12   b . The structural component  22 , in this embodiment, includes three independent, elongated tubes  26   a ,  26   b  and  26   c . The tubes  26  may be formed from aluminum, from composites, or any other suitable material. Tubes  26   a  and  26   c  are each coupled at an end near a root of the wing  12   b  to a driving implement  28 . Driving implement  28  may comprise an electric motor, an hydraulic actuator, or any other suitable form of implement for rotating the tubes  26   a  and  26   c . Tube  26   a  can be seen to have a first cutout  26   a   1  near a tip of the wing  12   b , and a second cutout  26   a   2  near the root of the wing. In this embodiment the center tube  26   b  includes only a single cutout  26   b   1  and is not coupled to the driving implement  28 . Tube  26   c , however, includes a pair of cutouts  26   c   1  and  26   c   2 . Tube  26   a  is also illustrated in  FIG. 2C . It will be noted that cutouts  26   a   1  and  26   a   2  are angularly displaced from one another by about 90°. The same is true for cutouts  26   c   1 ,  26   c   2  in tube  26   c.    
     Referring to  FIG. 2A , when the tubes  26   a ,  26   b  and  26   c  are orientated as illustrated in  FIG. 2 , the hinge line formed has a negative sweep, as shown in  FIG. 2A . During flight, the natural aerodynamic bending force on the wing  12   b , with the hinge line  18  as orientated as shown in  FIG. 2A , will cause the leading edge  24   c  of the wing  12   b  to twist upwardly, as shown in  FIG. 2B . The degree of twisting is at a maximum at the wing tip  24   b.    
     To change the sweep of the hinge line, the driving implement  28  is used to rotate the tubes  26   a  and  26   c  approximately 90°. This places the cutouts  26   a   1  and  26   c   2  in upright facing orientations which changes the positions of localized hinge areas in the tubes  26   a  and  26   c . With tubes  26   a - 26   c  positioned as shown in  FIG. 3 , the hinge line produced has a positive sweep, as illustrated in  FIG. 3A . This enables the tip  24   b  of the wing  12   b  to be twisted by aerodynamic forces being experienced by the wing  12   b  such that the tip  24   b  (as well as the leading edge  24   c ) is twisted downwardly in accordance with arrow  32  in  FIG. 3B . Thus, by simply rotating each of the tubes  26   a  and  26   c  by 90°, the hinge line on the wing  12   b  can be significantly and controllably changed. The natural aerodynamic forces acting on the wing  12   b  contribute significantly to twisting of the wing tip  24   b.    
     It will be appreciated that while only two cutouts have been illustrated in each of the tubes  26   a  and  26   c , that more or less than two cutouts could be employed. Additionally, the dimensions and shape of each cutout could be altered to tailor the localized hinge areas in each tube  26  as needed to form the desired hinge line or hinge lines. A greater or lesser number of tubes  26  could be employed to suit the needs of specific applications, and the lengths of the tubes  26  can be tailored to the length and shape of the wing  12   b.    
     Referring to  FIG. 4 , an elongated structural component  50  in accordance with an alternative embodiment of the present system and method is illustrated. The structural component  50  includes a plurality of elongated structural members  52   a ,  52   b  and  52   c . Each of the structural members  52   a - 52   c  includes generally perpendicularly extending panels or walls  54   a   1 - 54   a   4 . Panel  54   a   3  has a cutout  56  while panel  54   a   4  has a cutout  58  arranged approximately 90 degrees from cutout  56 . Structural member  52   b  includes only a single cutout  60 , while structural member  52   c  includes cutouts  62  and  64  disposed angularly about 90° from one another and at opposite ends thereof. Each of the cutouts  56 - 64  form a localized hinge area in their respective structural members  52   a ,  52   b  and  52   c . When the cutouts  56 - 64  are arranged as shown in  FIG. 4A , then negative sweep hinge line  18  is formed on the wing  12   b , as shown in  FIG. 4A . When the driving implement  28  is used to rotate the structural members  52   a  and  52   c  approximately 90°, such that cutouts  56  and  64  are facing upwardly, as shown in  FIG. 5 , then the positive sweep hinge line  20  is produced as shown in  FIG. 5A . Again, the number and precise location of each of the cutouts used on the structural members  52   a ,  52   b  and  52   c  can be varied to control the localized hinge areas in the wing  12   b  to produce a hinge line having a desired orientation on the wing  12   b . The structural members  52   a ,  52   b  and  52   c  could be formed from aluminum, from composites, or any other suitably strong, lightweight material. 
     Referring to  FIGS. 6 and 6A , still another structural component  70  representing another alternative embodiment of the present system and method is illustrated. Structural component  70  comprises a plurality of sleeved structural members  72   a ,  72   b  and  72   c  that may be of identical construction. A portion of member  72   a  is shown in  FIG. 6A . In  FIG. 6A , member  72   a  can be seen to include an outer tubular member  74  and an inner tubular member  76  having a plurality of opposing cutout portions  78  and  80 . Thus, when portion  74  is slid relative to portion  76 , the cutout areas  78  and  80  form a localized hinge area in the overall support member  72   a . Preferably, portion  74  has a wall thickness which is substantially less than the wall thickness of portion  76 , so that the majority of stiffness of each structural member  72  is significantly influenced by the position of its associated inner tubular member  76 . Thus, by controllably positioning the outer tubular member  74  relative to inner tubular member  76 , one can change the longitudinal hinge point in the support member  72   a.    
     With further reference to  FIG. 6 , each of the sleeved support members  72   a  can be controlled by the driving implement  28  such that the inner member  76  associated with each is longitudinally moved to a desired position to produce a localized hinge line in the wing  12   b . The positions of the inner members  76  can thus be aligned to produce a hinge line having a negative sweep, a positive sweep, or virtually any intermediate sweep angle that may be desired. 
     In  FIG. 7 , an alternative structural component  90  is illustrated. Structural component  90  forms a tube having a spiral cutout  92  extending over an angular orientation of about 90°. By rotating the tube  90 , the precise location of the hinge area that it forms can be infinitely adjusted along the 90° arc defined by the spiral cut-out  92 . For example, in the drawing of  FIG. 7 , rotating the structural component  90  counterclockwise according to arc line  94  will cause the localized hinge area to move in the direction of arrow  96 . Rotating the structural component  90  clockwise would cause the localized hinge area to move in a direction opposite to line  96 . 
     From the foregoing, the various embodiments of the structural component, taken together with the driving implement, can be used to create localized hinge areas in the wing that form a hinge line having a desired sweep. It is a particular advantage of the present system that the natural aerodynamic forces acting on the wings  12   a ,  12   b  can be used to twist the tips of the wings  12   a ,  12   b . Controlling the sweep of the hinge line on each wing  12   a ,  12   b  can contribute to producing highly maneuverable aircraft. The ability to controllably change the hinge line on each wing, using the natural aerodynamic forces experienced by the wing, rather than large, expensive and heavy motors or actuators, further enables the present system to be implemented on smaller, lighter aircraft where conventional wing twisting systems might not be possible, practical or cost effective. 
     While various embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the present disclosure. The examples illustrate the various embodiments and are not intended to limit the present disclosure. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.