Abstract:
A rotary wing with a curved outer surface, inlet openings and an edge foil for use in helicopters to improve lift and efficiency, maximizing the gross weight lift and the horizontal flight speed capabilities and minimizing performance penalties and unstable, inefficient operation.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit from U.S. Provisional Patent Application No. 62/247,325, filed Oct. 28, 2015, the contents of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    This disclosure relates to a rotary winged aircraft capable of vertical takeoff and landing. Currently existing rotary blade aircraft suffer from several design limitations that limit the gross weight lift and horizontal flight speed capabilities with performance penalties that make for unstable and inefficient operation. 
         [0003]    The conventional rotary blade system for helicopters provides lift by coupling more than one rotor blade to a relatively vertical shaft around which the blades rotate. The rotating blades generate lift by creating low-pressure above the blades and directing air flow downward. This lift is transferred to the helicopter through a coupling of the rotating blades to the shaft, and the housing of the shaft within the helicopter. The lift and horizontal flight speed capabilities of helicopters are limited by a variety of factors such as vehicle gross weight, blade configuration, blade rotation speed, blade drag, etc. There is a need for reductions in the limitations which affect these performance characteristics of helicopters so that lift and horizontal flight speed capabilities may be improved, in addition to overall helicopter flight stability and efficiency. 
       SUMMARY 
       [0004]    An object of the present invention is to propose a rotary wing with the general shape of an airfoil, much like the shape of an airfoil that is commonly used on fixed wing airplanes, around its perimeter. The top of the airfoil is longer than the underside, accelerating airflow laterally over the top of the wing during lateral movement, via the Bernoulli effect, and accelerating airflow downward over the edge of the wing via the Coanda effect. The preferred embodiment has a generally paraboloid-shape with a convex-shaped top outer surface and a concave-shaped inner surface with a plurality of inlet openings for the movement of directed air, an edge foil surrounding and connecting an outer shell circumference which may enclose the inlet openings, and inward blades utilized to draw air under the shell and downward, thereby directing an aircraft upward. The wing could be shaped in various manners, with a curved top outer surface, in order to produce the effects of accelerated lateral movement of air over the top of the wing, and accelerated downward movement of air over the edge of the wing. Embodiments may include one of the following features, or any combination thereof. 
         [0005]    In one aspect, a heavy-lift high-speed rotary wing may be made of a variety of materials and shaped in manners which would accelerate downward airflow via the Coanda effect, while also accelerating lateral airflow via the Bernoulli effect. The rotary wing may be in the general shape of a paraboloid with a convex-shaped top outer surface, a concave-shaped inner surface, at least one central hole through and around the top center of the shell, and an outer shell rim which lies in a shell plane. An interior volume may exist between the inner surface of the shell and the shell plane, The perimeter of the central hole or holes in the shell may be coupled to a tube or multiple tubes extending into the interior volume, toward a vehicle such as a helicopter. There may be at least two inlet openings in the shell, symmetrically located around the central hole, the inlet openings allowing air to be drawn via the rotation of the rotary wing around its central axis which is at the center of the central hole or holes and perpendicular to the shell plane. The shell may have an edge foil surrounding the outer shell rim circumference and connecting the ends of blades and the edge foil may enclose the inlet openings. The blades may exist proximate and below each inlet opening, where each blade has a leading face that creates a vacuum to draw air through the inlet openings. There may be a plurality of attachment structures to transfer rotary motion to the rotary wing and to transfer lift from the rotary wing to a vehicle to be lifted by the rotating shell. 
         [0006]    In another aspect, at least two inlet openings may be evenly spaced around the shell and they may be of a variety of shapes such as circular, oval, teardrop or other shapes symmetrically located on the shell. There may be at least two blades proximate and below the inlet openings. This symmetry attempts to negate possible adverse effects from leading faces of the blades. In addition, the edge foil that is coupled to the outer shell rim along the shell plane may be directed downward, below the shell plane. The edge foil may be angled toward a point where the central axis intersects the shell plane, but it may also be directed parallel to the central axis or even angled slightly away from the central axis. This shape of the shell and edge foil allow an aircraft to have forward motion without the characteristic losses and instabilities of a standard helicopter blade system. 
         [0007]    In one embodiment, a tube may extend downward from the inner surface of the shell, around the perimeter of the central hole, and end proximate the shell plane. This tube length optimizes the air flow up and down the tube and the pressurization within the interior volume, both of which increase the lift capabilities of an aircraft. The tube could be multiple tubes within a larger tube or multiple individual tubes, each coupled to the inner surface of the shell to enable the flow of air in or out of the tubes. One or more of the tubes may extend downward from the inner surface of the shell, around the perimeter of the central hole, and end proximate the shell plane. 
         [0008]    In one aspect, each blade may also feature a trailing face behind which air is pressurized and accelerated downward toward a vehicle such as a helicopter. Each blade may be symmetrically shaped so that the angle of the leading face is equal and opposite to that of the trailing face, but the shapes of the blades and angles of the leading and trailing faces could be varied, while remaining balanced under the shell. The air flows and pressures generated by the leading and trailing faces of each blade, provide the lift which directs the rotating shell upward, in the trajectory of the central axis around which the shell rotates. 
         [0009]    In another embodiment, the upper ends of the blades may be coupled to the inner surface of the shell along the perimeters of the inlet openings which may be arc-shaped when viewed parallel to the shell plane. Inlet openings may be of a variety of shapes such as circular, oval, teardrop or other shapes symmetrically located on the shell. In yet another aspect, the lower ends of the blades may lie proximate the shell plane with the leading and trailing blade faces extending from the outer shell rim toward the central axis. The wing could feature two or more inlet openings of multiple possible shapes and two or more blades of a variety of possible shapes, as long as they are evenly spaced under the shell around the central axis. The wing could also feature an edge foil that extends downward from the shell rim and parallel to the central axis or angled slightly outward, away from the central axis. In this non-limiting example, each blade may be coupled to an attachment structure, and each attachment structure may be coupled to a hub through which rotational forces may be transferred between the rotary wing and an aircraft. Attachment structures may be in a variety of potential locations coupling the shell to a vehicle which provides rotary motion to the shell, and to which lift may be provided from the shell. 
         [0010]    In another aspect, a rotating paraboloid-shaped shell allows the rotary wing to create a vacuum above it via the Coanda effect, accelerating airflow outward along the top, outer surface of the shell, and downward over the edge foil. This feature of the paraboloid-shaped shell increases the downward flow of air at the edge foil of the rotary wing as compared to existing blade designs which generate vortices at the ends of individual rotating blades. The inventive shell and edge foil combination may enable the rotary wing to behave as an airfoil while minimizing blade-end turbulence, and therefore increasing useable downward air flow. Reduced turbulence provides greater overall flight stability. 
         [0011]    In one embodiment, as the rotational speed of the rotary wing increases, airflow may return as a column of airflow at the center of the wing and then flow through the interior volume of the shell where inside surfaces of the blades may create a vacuum via the Bernoulli effect and accelerate the airflow downward. Some of the airflow may escape upward through the tube or tubes and out the top of the shell. In addition, some of the airflow through the interior volume may be directed toward the edge foil and accelerated by the edge foil. 
         [0012]    The outer surface of the shell and the edge foil may behave as an airfoil as utilized in a fixed-wing aircraft. The airfoil shape allows the rotary wing to accelerate downward airflow via the Coanda effect, while also accelerating lateral airflow via the Bernoulli effect. Lift may be generated through the movement of air over the surface of the wing and the air moved by the effects of the leading face and the trailing face of each blade residing within a space comprised of the interior volume and a space circumscribed by the edge foil, Existing blade designs generate and control lift by increasing the speed of the blade rotation, adjusting the leading edge angle of the rotating blades, and adjusting the blade system&#39;s angle of attack. Lift generated by the rotary wing may be controlled by the speed of its rotation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIGS. 1 a  and 1 b    are top views of an embodiment of a heavy lift-high speed rotary wing, isolated and mounted on an aircraft, respectively. 
           [0014]      FIGS. 2 a , 2 b , and 2 c    are bottom views of embodiments of a heavy lift-high speed rotary wing; isolated, isolated alternate configuration, and mounted on an aircraft, respectively. 
           [0015]      FIG. 3  is a side view of an embodiment of a heavy lift-high speed rotary wing. 
           [0016]      FIG. 4  is a perspective view of a bottom of an embodiment of a heavy lift-high speed rotary wing. 
           [0017]      FIG. 5 a    is a view of cross-section  5 - 5  from  FIG. 1   a.    
           [0018]      FIG. 5 b    is a perspective view of cross-section  5 - 5  from  FIG. 1   a.    
           [0019]      FIG. 6  is an isometric side-bottom view of an embodiment of a heavy lift-high speed rotary wing mounted to an aircraft. 
           [0020]      FIGS. 7 a  and 7 b    are descriptions of airflow during vertical flight of an embodiment of a heavy lift-high speed rotary wing; side view of wing and aircraft, side view with one blade and part of aircraft, respectively. 
           [0021]      FIG. 8  is a description of airflow during high speed horizontal flight of an embodiment of a heavy lift-high speed rotary wing. 
           [0022]      FIG. 9  is a detail view of a blade of the heavy-lift high speed rotary wing. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    The device described herein is one non-limiting example of a rotary wing constructed and arranged to enable efficient and stable heavy lifting without compromising the high speed forward flight of a vehicle such as a helicopter. The rotary wing reduces helicopter performance penalties incurred by conventional helicopter main rotor designs. The device could be utilized in a variety of other applications which involve the movement and pressurization of air or other masses. The preferred embodiment has the general shape of a paraboloid with a convex-shaped top outer shell surface ending at an outer shell rim. The shell need not be paraboloid shaped as long as it has a curved top outer surface so that it will behave as an airfoil, in that airflow above the wing is accelerated as compared to airflow below the wing. Therefore, various shapes may suffice, including but not limited to those that are close to being paraboloid-shaped, thus the scope is not limited to a strictly paraboloid shape. Embodiments may include one of the following features, or any combination thereof. 
         [0024]      FIG. 1 a    is a top view of an embodiment of a heavy lift-high speed rotary wing  10  comprising a shell  11  made of a variety of materials in the general shape of a paraboloid with a convex-shaped top outer surface  19 , at least one hole  12  through the top of the shell  11 . There are a plurality of inlet openings  13  (in this non-limiting example there are three inlet openings  13  spaced at 120 degree intervals evenly spaced around the shell). There should be at least two openings, and the openings should be evenly spaced around the shell in order to balance forces created as the wing spins. The entire rotary wing is preferably circumscribed by an edge foil  15 . A plurality of attachment structures  18  are visible through hole  12 .  FIG. 1 b    shows rotary wing  10  mounted upon aircraft  20  with tail  23  protruding laterally. Openings  13  are, in this example, generally arc-shaped when viewed from above, but they do not need to have this shape as long as they function to allow airflow through them, as further explained herein. 
         [0025]      FIG. 2 a    is a bottom view of a heavy lift-high speed rotary wing  10 . Shell  11  is circumscribed by airfoil  15  and has a plurality of inlet openings  13  facing a plurality of concave downward and inward blades  14  coupled to attachment structures  18 .  FIG. 2 b    shows rotary wing  10  with multiple holes  12   a  around hub  21 , revealing an alternate configuration from that shown in  FIG. 2 a   .  FIG. 2 c    shows rotary wing  10  mounted upon aircraft  20  with tail  23  protruding laterally. 
         [0026]      FIG. 3  is a side view of a heavy life-high speed rotary wing  10 . A non-limiting example of attachment structures  18  may be seen more clearly as they extend downward from where they are coupled to concave-shaped inward blades  14 . In this embodiment, edge foil  15  is directed downward from outer shell rim  23  and angled inward. Attachment structures  18  couple to hub  21  and each inlet opening  13  connects to, and is encompassed by, edge foil  15 . 
         [0027]      FIG. 4  is a perspective view of a bottom of a heavy lift-high speed rotary wing  10  comprising a paraboloid-shaped shell  11 . There are a plurality of inlet openings  13  (in this non-limiting example there are three inlet openings  13  spaced at 120 degree intervals evenly spaced around the shell) with the entire rotary wing circumscribed by edge foil  15  with exterior surface  25  and interior surface  35 . A plurality of attachment structures  18  join at hub  21 . In this embodiment, blades  14  have an inside surface  34  and are coupled to attachment structures  18 , blades  14  extending and coupling to shell  11 , along the perimeter of inlet openings  13 . The blades need to be proximate the openings but do not necessarily need to lie along the perimeters of the openings. Tube  17  is coupled to shell  11 , extending downward from inner surface  31  of shell  11 . 
         [0028]      FIG. 5 a    is a cross-sectional view of a heavy lift-high speed rotary wing  10  taken along line  5 - 5  of  FIG. 1 a   . This view provides a clear depiction of an embodiment of blades  14  located below shell  11 . Also, two attachment structures  18  can be seen in order to understand how rotary wing  10  may be attached to an aircraft along central axis  16  at hub  21 . In this embodiment, tube  17  is coupled to shell  11  along the perimeter of hole  12  in shell  11 , tube  17  extending downward to its end located proximate shell plane  27  established by outer shell rim  23 . Tube  17  could potentially be shorter or longer than this. Edge foil  15 , with interior surface  35 , faces blades  14  and is coupled to shell  11  at outer shell rim  23 . Edge foil  15  is angled toward a point  29  where central axis  16  intersects shell plane  27 , such that the edge foil is neither parallel with, nor perpendicular to the shell plane. 
         [0029]      FIG. 5 b    is a bottom perspective view of a heavy lift high speed rotary wing  10  taken along line  5 - 5  of  FIG. 1 a   . This view lends clarity to an embodiment of rotary wing  10  with blades  14  having a concave-shape, a shape and position of the tube  17 , and one of the potential locations for attachment structures  18  with connections to hub  21 . An angled view of inlet openings  13  and edge foil  15 , with interior surface  35  and exterior surface  25 , can also be seen for this embodiment of wing  10 . 
         [0030]      FIG. 6  is a perspective side-bottom view of the heavy lift-high speed rotary wing  10  mounted upon vehicle  20 . Tube  17  is attached to inner surface  31  of shell  11  along the perimeter of hole  12 . In this embodiment, rotary wing  10  is rotated around axis  16  via hub  21  through a plurality of attachment structures  18 . Attachment structures  18  are attached to blades  14 , but they do not need to be attached to the blades. Blades  14  attach to inner surface  31  of shell  11  along the arc-shaped perimeters of inlet openings  13  in shell  11 . A variety of other structures for attaching the shell to the aircraft are contemplated and included herein, each depending on the construction of the wing and the manner in which the wing is coupled to a particular aircraft. 
         [0031]      FIGS. 7 a  and 7 b    illustrate airflow while the rotary wing  10  is rotated counter-clockwise [viewed from above] during vertical operation. Operation is identical for clockwise operation but this figure describes counter-clockwise operation. The airflow arrows  40 ,  41 ,  42  and  43  denote airflow in the direction of the arrows, with the arrow&#39;s relative length denoting air speed and relative width denoting volume of airflow. The leading face  54  of blades  14  creates a vacuum drawing airflow  41  into inlet openings  13  in shell  11 . The trailing face  64  of blades  14  then accelerates the airflow  42  downward. Shell  11  additionally creates a vacuum above it via the Coanda effect and accelerates airflow  41  outward where exterior surface  25  of edge foil  15  via the Coanda effect accelerates it downward joining airflow  42 . Airflow  42  becomes a laminar flow downward for a distance before returning as a column of airflow  43  toward tube  17  (best viewed on  FIG. 4 ) of the of the heavy lift-high speed rotary wing  10 . The airflow  43  then flows through the interior volume of the heavy lift-high speed rotary wing  10  where inside surface  34  of blades  14  (best viewed on  FIG. 4 ) creates a vacuum via the Bernoulli effect and accelerates the airflow  40  downward in a parallel laminar flow. In addition, some of the returning airflow  43  escapes through tube  17  (best viewed on  FIG. 4 ) where it joins the airflow  41  accelerated by outer surface  19  of shell  11 . This action is replicated for the plurality of inlet openings  13  and blades  14 . Inner surface  31  of shell  11  (best viewed on  FIG. 4 ) functions similar to outer surface  19  of shell  11  (best viewed on  FIG. 3 ) and assists via the Coanda effect in accelerating airflow  43  toward interior surface  35  of edge foil  15  (best viewed on  FIGS. 4, 5   a  and  5   b ) where it functions like exterior surface  25  of edge foil  15  (best viewed on  FIG. 4 ) and via the Coanda effect accelerates airflow  43  into laminar airflow  40 . Laminar airflow  42  and  40  trap airflow  43  and with the addition of airflow  41  substantially raises the air pressure under the heavy lift-high speed rotary wing  10  contributing to the heavy lift ability of the heavy lift-high speed rotary wing  10 . 
         [0032]      FIG. 8  describes airflow while the heavy lift-high speed rotary wing  10  is experiencing horizontal flight. The airflow arrows  45  denote airflow in the direction of the arrows with the relative length of the arrows denoting airspeed. The totality of outer surface  19  of shell  11  and exterior surface  25  of edge foil  15  define an airfoil much like the shape of an airfoil that is commonly used on fixed wing airplanes where the top of the airfoil is longer than the underside and accelerates airflow via the Bernoulli effect. Shell  11  and edge foil  15  protect blades  14  from strongly interacting with the free stream air flow  45 . This protection prevents potential roll problems commonly associated with rotary winged aircraft during high speed horizontal flight where the attacking wing generates more lift than the retreating wing. 
         [0033]      FIG. 9  illustrates a blade  14  from a heavy lift-high speed rotary wing with leading face  54  and trailing face  64 . Blade inside surface  34  is on the convex side of blade  14  and blade outside surface  24  is on the concave side of blade  14 , blade outside surface  24  facing the interior surface  35  of the edge foil  15 . 
         [0034]    A number of implementations have been described. Nevertheless, it will be understood that additional modifications may be made without departing from the scope of the inventive concepts described herein, and, accordingly, other embodiments are within the scope of the following claims.