Patent Document

BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention generally relates to aircraft and particularly relates to flight control of aircraft without external, aerodynamic control surfaces.  
           [0003]    2. Description of the Prior Art  
           [0004]    In a typical aircraft, moveable aerodynamic control surfaces are installed on wings or other portions of the aircraft that are exposed to the airflow during flight. These control surfaces are moveable relative to the aircraft and include, for example, ailerons, trim tabs, canards, and rudders. These surfaces use aerodynamic effects to cause moments in the yaw, pitch, and roll directions for controlling the orientation of the aircraft or for stabilizing the aircraft during flight. Moveable, external control surfaces are complicated, requiring many parts and adding to the weight of the aircraft. Another characteristic of external control surfaces which may be undesirable is that they create drag in operation. Also, the radar cross-section of an aircraft increases when the control surfaces are displaced from their nominal positions, reducing the stealth characteristics of the aircraft.  
           [0005]    Modern aircraft advances include vectored thrust and internal engines. Vectored thrust is used in vertical takeoff and landing (VTOL) or short-takeoff and vertical landing (STOVL) applications and for producing quicker maneuvers or allowing steeper angles of attack. Thrust vectoring is done externally, generally by using a rotating or articulating nozzle.  
           [0006]    In some military applications, engines are installed deep within the body of the aircraft. Though this tends to reduce the external heat signature and reduce the exposed surfaces that would increase the radar cross-section of the aircraft, it is more difficult to implement thrust vectoring.  
           [0007]    SUMMARY OF THE INVENTION  
           [0008]    An apparatus and method for flight control of an aircraft provides a body with adjustable intake ports ducting air into an internal intake manifold. Adjusting the openings of the intake ports changes the amount of air flowing over the surfaces surrounding the intakes, changing the amount of lift created by those surfaces. The intake manifold feeds air to at least one engine, and an exhaust manifold communicates the exhaust of the engine to exhaust exit ports. The exhaust manifold contains a plurality of moveable components that direct exhaust within the exhaust manifold and to particular exhaust exit ports for producing various levels of force imbalance among the exit ports. A compressor powered by the engine provides air to bleed-air ports on the wings for creating roll moments. Varying lift on the forward surfaces with the intake ports, vectored exhaust, and bleed air are used to control and stabilize the aircraft during flight, obviating the need for aerodynamic control surfaces.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    The novel features believed to be characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings.  
         [0010]    [0010]FIG. 1 is a top view of an aircraft constructed in accordance with the present invention.  
         [0011]    [0011]FIG. 2 is a top view of the aircraft in FIG. 1 showing the components in a second orientation.  
         [0012]    [0012]FIG. 3 is a top view of the aircraft in FIG. 1 showing the components in a third orientation.  
         [0013]    [0013]FIG. 4 is a sectional view of the rear portion of the aircraft of FIG. 1.  
         [0014]    [0014]FIG. 5 is a rear view of the rear portion of the aircraft of FIG. 1.  
         [0015]    [0015]FIG. 6 is a sectional view of the rear portion of the aircraft of FIG. 1 showing the components in a second orientation.  
         [0016]    [0016]FIG. 7 is a sectional view of the rear portion of the aircraft of FIG. 1 showing the components in a third orientation.  
         [0017]    [0017]FIG. 8 is a sectional view of the rear portion of the aircraft of FIG. 1 showing the components in a fourth orientation.  
         [0018]    [0018]FIG. 9 is a top view of a second embodiment of an aircraft constructed in accordance with the present invention, the aircraft being a VTOL or STOVL configuration.  
         [0019]    [0019]FIG. 10 is a front view of the aircraft of FIG. 9.  
         [0020]    [0020]FIG. 11 is a sectional view of a second embodiment of the rear portion of the aircraft of FIG. 1.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    Referring to FIG. 1, aircraft  11  has a diamond-shaped body and integrated wings with no external aerodynamic flight control surfaces. The right side of the figure shows the upper exterior of aircraft  11 , whereas the left side of the figure shows the upper surface  13  removed, exposing the inner portion of lower surface  15  and the internal components. A cockpit  17  is located in the front portion of aircraft  11  for containing a pilot. Alternatively, aircraft  11  may be an unmanned aerial vehicle (UAV), in which the cockpit  17  may contain computers for controlling aircraft  11  and payload, or the computers maybe located elsewhere in aircraft  11 , obviating the need for cockpit  17 .  
         [0022]    Air intake ports  19  are positioned to either side of cockpit  17  and on upper surface  13  and on lower surface  15 . For each surface, the number of intake ports  19  on each side of cockpit  17  is equal, though the number of intake ports  19  on surfaces  13 ,  15  may differ. Also, the number and size of intake ports  19  may differ for various aircraft configurations and sizes. Each intake port  19  has a sliding door (not shown), like those shown in FIGS. 4 through 8, for modulating the amount of airflow entering intake port  19  and passing into an intake manifold  21  located in the forward section of aircraft  11 . By modulating the amount of airflow entering intake ports  19 , the remaining airflow over surfaces  13 ,  15  is altered, changing the amount of drag and lift created by surfaces  13 ,  15  and causing pitch moments to develop. These pitch moments cause aircraft  11  to move toward a nose-down or nose-up attitude. For example, restricting air entering the intake ports  19  on lower surface  15  causes more air to travel over lower surface  15 , creating more lift on lower surface  15 . This lift creates a pitch moment, tending to cause the nose of aircraft  11  to move downward. Closing ports on one side of upper surface  13  and the opposite side of the lower surface  15  produces a roll moment, the side of upper surface  13  with the closed ports tending to move upward, the opposite side of lower surface  15  tending to move downward.  
         [0023]    Intake manifold  21  provides intake air to one or more engines, which, in multiple engine configurations, may be spaced apart and equidistant from the longitudinal centerline. Air in intake manifold  21  divides and passes into two engines  23 , the axes of engines  23  being oriented longitudinally and offset to either side of the longitudinal centerline of aircraft  11 . The air first enters a compressor  25 , preferably oversized, which pressurizes the air using rotating, bladed fans (not shown), then passes into a combustion section  27 . Fuel is added to the pressurized air, and the mixture is ignited to produce a rearward-directed exhaust of hot gases. These gases pass through bladed rotors (not shown) in a turbine section  29 , causing the rotors to rotate. The fans and the rotors are attached to a shaft (not shown) passing through engine. As the gases cause the rotors to rotate, the shaft rotates, causing the fans in compressor  25  to rotate for pressurizing the air entering engine.  
         [0024]    Air from each compressor  25  can also pass laterally into a bleed-air manifold  31  leading to bleed-air ports  33  on surfaces  13 ,  15  and into a crossover passage  34  connecting manifold  31 . Two sets of two bleed-air ports are located on each surface  13 ,  15 , and each set is laterally located equidistant from and on opposite sides of the longitudinal centerline of aircraft. Because bleed-air ports are located away from the centerline, air passing out of bleed-airports  33  creates roll moments, tending to cause aircraft  11  to rotate about a longitudinal line. For example, air passing out of the bleed-air ports  33  on the right side of lower surface  15  creates a roll moment tending to cause the right side of aircraft  11  to move upward. Each port also has a sliding door, like those shown in FIGS. 4 through 8, for covering the ports  33  and controlling the amount of bleed air passing through ports  33 .  
         [0025]    Adjustable vanes  35 ,  37 ,  39 ,  41  and wedges  43  are located within an exhaust manifold  45  for vectoring exhaust exiting from turbines  29 . The left side of FIG. 1 and FIGS. 2 and 3 show the forward primary vane  35 , rear primary vane  37 , secondary vanes  39 , left and right trailing edge vanes  41 , and exhaust wedges  43 . Forward primary vane  35  is between and immediately behind the exhaust exits of engines  25 , whereas rear primary vane  37  is located at the rear of the exhaust manifold directly behind vane  35 . Vanes  35 , 37  are bisected by a vertical plane passing through the central longitudinal axis of aircraft  11 . Two sets of secondary vanes  39 , one set being on each side of aircraft  11 , each comprise inner, middle and outer vanes  39 . Trailing edge vanes  41  are located along the trailing edges of aircraft  11 , downstream of primary vane  35  and secondary vanes  39 . Vanes  35 ,  37 ,  39 ,  41  pivot on vertical axes, whereas wedges  43  pivot on a horizontal axes. Primary vanes  35 ,  37  and secondary vanes  39  have a symmetric, teardrop-shaped horizontal cross-section with a rounded end and a tip. Trailing edge vanes  41  have a curved, airfoil-shaped horizontal cross-section and also have a rounded end and a tip. Wedges  43  have a shape as shown in FIGS. 4 through 8. The tips of vanes  37 ,  39 ,  41  are pointed upstream (toward the engines  23 ), whereas the tip of primary vane  35  points downstream. Manifold  45  also has fixed vanes  47  which direct airflow and provide structural support for manifold  45 . Though not shown, excess bleed air from bleed-air manifold  31  can be vented rearward along surfaces  13 ,  15  over exhaust manifold to cool surfaces  13 ,  15  and further reduce the heat signature of aircraft  11 .  
         [0026]    [0026]FIG. 1 depicts vanes  35 ,  37 ,  39 ,  41  in their orientation for forward flight with both engines  23  operating properly. Tips of primary vanes  35 ,  37  are oriented to bring their tips into alignment, wherein the tips are as near as possible to each other and are along the vertical plane passing through the longitudinal centerline. This orientation allows much of the exhaust from engines  23  to pass directly to primary exit ports  48 , causing a forward force on aircraft  11 , ports  48  being located to the rear of and on each side of rear primary vane  37 . Primary ports  48  have an opening on each surface  13 , 15 , as shown in FIGS. 4 through 8. Secondary vanes  39  are rotated to divert some of the exhaust exiting engines  23  toward trailing edge vanes  41 , and trailing edge vanes  41  are rotated to redirect the exhaust out of trailing edge ports  49 . Trailing edge ports  49  are located to each side of trailing edge vanes  41 , ports  49  comprising an opening on upper surface  13  and an opening on lower surface  15 , each opening having a door (not shown), like those for intake ports  19 , for closing each opening on each port  49 . Corresponding vanes  39 ,  41  on both sides of aircraft  11  have the same orientation during normal forward flight. Because the exhaust exiting trailing edge ports  49  is exiting at an angle relative to the longitudinal axis of aircraft  11 , the longitudinal vector component provides additional forward thrust, and the lateral component provides yaw stabilization of aircraft  11 . To cool the exhaust exiting ports  48 ,  49 , excess bleed air may also be vented around ports  48 ,  49  to reduce the infrared signature of the exhaust.  
         [0027]    The orientation of vanes  35 ,  37 ,  39 ,  41  for left yaw is shown in FIG. 2. Aircraft  11  yaws when a moment is created by more exhaust being directed out of trailing edge ports  49  on one side of aircraft  11  than out of ports on the other side. To direct more exhaust out of trailing edge ports  49  on the right side, as shown in the figure, secondary vanes  39  on the left side are rotated to restrict exhaust from passing forward of vanes  39 , causing more exhaust to pass into the center of manifold  45 . The tips of all trailing edge vanes  41  are rotated to the left to allow more exhaust to exit trailing edge ports  49  at greater angles relative to the longitudinal axis. The tip of forward primary vane  35  is rotated to the right side, causing more exhaust from the right engine to be diverted away from right primary exit port  48  and toward right trailing edge ports  49 . Likewise, the tip of rear primary vane  37  is rotated to the left, diverting more exhaust from the left engine to the right portion of manifold  45  and away from left trailing edge ports  49 . The thrust imbalance between the trailing edge ports  49  causes the nose of aircraft  11  to rotate to the left. To cause the nose to yaw to the right, the orientations of vanes  35 ,  37 ,  39 ,  41  are moved to positions that are the mirror of those of vanes  35 ,  37 ,  39 ,  41  in a left yaw orientation.  
         [0028]    A serious situation occurs when one of engines  23  is not operating, causing an imbalance in the amount of exhaust in the two sides of the exhaust manifold  45 . FIG. 3 depicts the orientation of vanes  35 , 37 , 39 , 41  when thrust from only one engine is available. In this instance, only the right engine is operating, and thrust must be provided throughout exhaust manifold  45  to prevent aircraft  11  from uncontrollably yawing to the left.  
         [0029]    To prevent exhaust of the right engine from passing forward through left engine, the tip of forward primary vane  35  is rotated to the left, and the inner left secondary vane  39  is rotated so that its tip is near the tip of forward primary vane  35 . The tip of forward primary vane  35  is rotated to the left for a much greater angle than is used during yaw maneuvers. The middle secondary vane  39  is rotated to position its tip near the rounded, downstream end of inner secondary vane  39 , and outer secondary vane  39  is rotated to position its edge near the rounded, downstream end of the middle secondary vane  39 . Vanes  39  act as a block, preventing exhaust from passing out of exhaust manifold  45  and forward through left engine. The tip of rear primary vane  37  is also rotated for a much greater angle than in yaw maneuvers, but to the right. Much of the exhaust moving toward the right primary exit port  48  is diverted by rear primary vane  37  toward the left side of exhaust manifold  45 . The inner, right-hand secondary vane  39  is positioned to divert exhaust from the right side of exhaust manifold  45 , working together with rear primary vane  37  for this purpose.  
         [0030]    [0030]FIGS. 4 through 8 show details of one of the movable exhaust wedges  43  located at the primary exit ports  48  and shown in FIGS. 1 through 3. Exhaust wedge  43  has an upper surface  51  and a lower surface  53 , each being concave in longitudinal cross-section, convex in lateral cross-section, and converging to an edge at the forward end of exhaust wedge  43 . The rear surface  55  of wedge  43  is in sliding contact with the inner surface  57  of the rear outer wall of aircraft  11 . Exhaust wedge  43  rotates about a horizontal axis  59  for moving the tip of each exhaust wedge  43  up or down to control the amount of exhaust directed through an upper opening  61  and a lower opening  63  of each primary exit port  48 . Each opening  61 ,  63  has a sliding door  65  for covering opening  61 ,  63  when exhaust wedge  43  is moved to a position that seals one of the openings  61 ,  63 , though only one opening  61 ,  63  can be sealed at a time. FIGS. 4 and 5 show exhaust wedge  43  in the forward flight position and doors  65  in their retracted positions. Exhaust exits both openings  61 ,  63 , providing forward thrust and vertical thrust vector components, the vertical thrust component assisting in pitch control and stability of aircraft  11 .  
         [0031]    To cause the maximum downward pitch moment (for quickly rotating the nose of aircraft  11  downward), the tip of exhaust wedge  43  is rotated upward, as shown in FIG. 6. Upper surface  51  near the leading end contacts a protrusion  67  on the upper inner surface of primary exit port  48  to seal upper opening  61 , preventing exhaust from exiting upper opening  61 . Door  65  for upper opening  61  is closed. The intersection of lower surface  53  and rear surface  55  aligns with the rear portion of lower opening  63 , causing all exhaust to be directed to lower opening  63 , door  65  being completely retracted. The imbalance of force due to exhaust passing through lower opening  63  without an opposing force through upper opening  61  causes a pitch moment, tending to cause the rear of aircraft  11  to move upward. This positioning of exhaust wedges  43  may also be used in a VTOL aircraft to provide some forward thrust, while also assisting in upward thrust.  
         [0032]    [0032]FIG. 7 shows exhaust wedge  43  in an upward-pitch orientation for causing the nose of aircraft  11  to pitch upward. Wedge  43  is rotated to position the leading end near a protrusion  69  on the lower inner surface of primary exit port  48 , diverting more exhaust toward upper opening  61  than in forward flight (FIG. 4). This causes an imbalance in thrust between openings  61 ,  63 , causing a moment tending to rotate the rear of aircraft  11  downward, pitching the nose of aircraft  11  upward. Exhaust wedges  43  can be rotated to seal the lower opening  63 , as described above for upper opening  61 , as shown in FIG. 8. Upper surface  51  of exhaust wedge  43  is in contact with protrusion  69 , providing maximum force to pitch the nose upward.  
         [0033]    Referring to the FIGS. 1 through 8, in operation, a pilot or computer controls the flight of aircraft  11  from cockpit  17 . Air for engines  23  flows into intake manifold  21  through the open doors on intake ports  19 . In level flight, the doors for the intake ports  19  on each side of the cockpit  17  will be open the same amount, though the doors on the upper surface  13  may be open a different amount than those on the lower surface  15 . The intake doors may be fully open or may be partially closed. Air travels from intake manifold  21  into compressor sections  25  of engine  23 , where the air is pressurized. A portion of the air is ducted to bleed-air ports  33  on the upper and lower surface  15  of wings. Bleed air may be released during normal, level flight to endure roll stability of aircraft  11 . Thrust is produced when exhaust passes rearward from the turbine sections  29  of engines  23 , into exhaust manifold  45 , and exits aircraft  11 . Exhaust exits out of aircraft  11  through primary exit ports  48  and trailing edge ports  49 , the amount of exhaust being equal on both sides of aircraft  11  for straight and level flight.  
         [0034]    To perform a roll maneuver in which the right wing move downward, the doors of intake ports  19  on the upper left and lower right portions of aircraft  11  are closed, producing greater lift on the surfaces  13 ,  15  surrounding these intake ports  19 . Additionally, bleed air is released from the upper right and lower left bleed-air ports  33 . The combination of the increased lift and bleed air cause aircraft  11  to roll, the right wing moving downward. Only one of the forces are needed to roll aircraft  11 , but using all of the available force sources causes a higher roll rate.  
         [0035]    To yaw aircraft  11 , primary vanes  35 ,  37  rotate in opposite directions to divert exhaust from on side of exhaust manifold  45  to the other side and from one primary exhaust exit  48  to the other exit  48 . Secondary vanes  39  rotate to positions which prevent exhaust from passing forward of vanes  39  on the side where less thrust is desired. Trailing edge vanes  41  also rotate to change the direction that trust moves out of trailing edge ports  49 . The combination of the orientation of vanes  35 ,  37 ,  39 ,  41  causes a larger amount of exhaust to exit on one side of aircraft  11 , causing aircraft  11  to rotate about a vertical axis, the nose moving to the side opposite the larger thrust.  
         [0036]    Pitch is induced through changes in lift at intake ports  19  and through changes in the orientation of exhaust wedge  43  at primary exit ports  48 . As described above for causing roll, the doors on intake ports  19  can be closed to produce more lift on the surrounding surface. When the intake doors on either the upper or lower surface  15  are closed, a lift force is created on that surface, causing the nose to move in the direction of that surface. Also, exhaust wedges  43  move to direct more or less flow out of upper opening  61  or lower opening  63  at the primary exit ports  48 . For example, as more exhaust is passed out of upper opening  61 , the nose of aircraft  11  pitches upward.  
         [0037]    An optional embodiment for the internal ducting of exhaust is shown in FIGS. 9 and 10. A vertical takeoff and landing (VTOL) aircraft  71  is shown in the figures. Aircraft  71  has two engines  73  which feed exhaust into an exhaust manifold  75 . Exhaust manifold  75  has moveable, internal vanes like those shown in FIGS. 1 through 3 and four exhaust ports  77  in the lower surface  79  of aircraft  71 . Ports  77  direct exhaust downward to lift the rear portion of aircraft  71 , ports  77  having sliding doors (not shown) for closing ports  77 . A gear-driven, ducted lift fan  81  is located in the forward portion of aircraft  71  for providing additional upward thrust. A gear box  83  located forward of engines  73  transfers torque from engines  73  to lift fan  81 . The air for lift fan  81  is not in communication with intake manifold  85 ; the air is drawn from above aircraft  71  through an opening  87  in upper surface  89 , as shown in FIG. 10. The air passes through lift fan  81  and exits aircraft  71  through an opening  91  (FIG. 10) in lower surface  79 .  
         [0038]    An alternate embodiment of a primary exit port  93  is depicted in FIG. 11. A center exhaust port  95  is located in the rear surface  97  and near the vertical center of the aircraft. An upper opening  99  and a lower opening  101  are positioned adjacent to center exhaust port  95 , each opening  99 ,  101  having a sliding door  103  near the outer surface of aircraft  11 . Between center exhaust port  95  and each opening  99 ,  101  is a moveable vane  105 ,  107 , each rotating on a horizontal axis  109 ,  111 . Vanes  105 ,  107  rotate between inner and outer positions, the leading ends of vanes  105 ,  107  being in contact when vanes  105 ,  107  are in their inner positions. Vanes  105 ,  107  are shown in the figure in their inner position, diverting exhaust to openings  99 ,  101  and preventing exhaust from exiting through center exhaust port  95 . When upper vane  105  is in the inner position, upper vane  105  diverts exhaust upward toward upper opening  99 . When upper vane  105  is in the outer position, exhaust passes to the center exhaust port  95  and is prevented from passing into upper opening  99 , the inner end of which is covered by upper vane  105  as the leading end of vane  105  contacts an upper, inner surface  113  of exhaust manifold  45 . Lower vane  107  operates in the same manner as upper vane  105 , but lower vane  107  does not rotate to a position in which the tip of vane  107  contacts the lower, inner surface  115  of exhaust manifold  45 . Instead, lower opening  101  always remains at least partially open, allowing exhaust to pass through lower opening  101 .  
         [0039]    The present invention allows an aircraft to be controlled in flight without the use of external aerodynamic control surfaces. The many advantages include reduced complexity and weight, reduced radar cross-section, reduced drag, and higher maneuver rates. Control of the aircraft when an engine is out is greatly improved by a means for balancing thrust between the left and right sides of the aircraft. Also, the various embodiments provide for VTOL capability with little or no changes to aircraft.  
         [0040]    While the invention has been shown in only a few of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit thereof.

Technology Category: 4