Abstract:
An aircraft with wings that may be fixed for flight and which swing and fold for storage and for maneuvering and otherwise operating the aircraft while not in flight is disclosed. An embodiment includes wings which swing backwards and through the body of the aircraft and then fold by drooping elevons which span the trailing edges of the wings along the sides of the body. Another embodiment includes wings which swing forward and control surfaces which fold upwards at the sides of the aircraft. The invention provides for a narrow width for the aircraft when not in flight using a simple mechanism.

Description:
BACKGROUND OF THE INVENTION 
     The invention concerns an aircraft with wings which are fixed for flight and which may both swing and fold when the aircraft is not in flight. 
     Aircraft have been using wings to make manned, controlled flights for over 100 years, starting with the airplane flown by the Wright brothers in 1903. Aircraft have advantages in speed and freedom of movement, yet they are, compared with many machines of similar complexity, relatively rare. Aircraft have only been produced in numbers of a few thousand of each individual type. Aircraft use has been confined mainly to warfare and to the carrying of paying passengers in largest and fastest airplanes practical between huge airports on the outskirts of large cities. The inventor supposes the lack of production of aircraft and of flexibility in their use may be due in part to the difficulty in storing airplanes and maneuvering them when not in flight. 
     Airplanes lift themselves by the action of fixed wings on the air, and the greater the amount of air, the more efficient is the lifting. This fact makes a large wingspan, as compared with the weight of the aircraft, very important to high efficiency. Only with structurally efficient materials, design and construction can an airplane be equipped with efficient wings. Such wings, which are rigid and span a relatively large space, have made airplanes difficult to store. Only airplanes designed for naval warfare, and so for storage aboard ships, have commonly used wings that are customarily folded upon landing and then unfolded again for flight. The inventor supposes an aircraft with folding wings that offer sufficient benefit in comparison with their added weight and cost has been lacking. 
     An exemplary design for an airplane for naval warfare is that of the F-14 Tomcat, which was constructed with wings that swing, rather than fold. That is, the wings rotate approximately in their own plane, maintaining the same orientation with the ground, and rotating about an essentially vertical axis. The swinging wings are useful to reduce wing span not only for storage aboard ship, but also to greatly improve speed and maneuvering while flying at high speeds. With swinging wings, however, the solid area of the aircraft when viewed from above, that is in plan or in the top view, is essentially unchanged, the F-14 barely fit aboard the largest ships, and the F-14 cannot itself operate on the water. 
     Airplanes are challenging to store because they are designed to fly. One aspect of this challenge is that a parked airplane may be blown about by a strong wind, especially if the airplane is relatively light, such as an airplane for carrying a few people. Swinging wings, such as those on the F-14, do only a little to reduce this problem, since they reduce wing span but do not significantly reduce the solid area of the aircraft in plan. Known folding wings may reduce the solid area of an aircraft in plan, but if so, they typically add solid area in the side view, area which is also affected by winds on the ground or at sea. Another aspect of this challenge of storage is that the wings may be somewhat easily damaged while on the ground or at sea, and swinging alone or folding alone typically does little or nothing, besides reducing wing span, to protect the wings. 
     BRIEF SUMMARY OF THE INVENTION 
     An object of the invention is to provide an aircraft with wings that may be fixed for flight and which may both swing and fold when the aircraft is not in flight, to reduce the space required to maneuver and otherwise operate the aircraft when not in flight and to store the aircraft. An aspect of the invention is that the fixed, swinging and folding wings provide sufficient wing span for efficiency in flight and then greatly reduce the width of the aircraft when it is not in flight. An aspect of an embodiment of the invention is that the fixed, swinging and folding wings substantially reduce the solid area of the aircraft in plan, and keep nearly constant the solid area of the aircraft when viewed from other directions. An aspect of an embodiment of the invention is that the fixed, swinging and folding wings may be stored in part within the body of the aircraft for protection. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan or top view of an aircraft with fixed, swinging and folding wings, showing both a position for flight and a stored position (dotted lines). 
         FIG. 2  is a plan or top view of the same aircraft with fixed, swinging and folding wings, showing a stored position. 
         FIG. 3  is an elevation or side view of the same aircraft with fixed, swinging and folding wings, showing a stored position. 
         FIG. 4  is a plan view of another aircraft with fixed, swinging and folding wings, with a wing in a position for flight and a wing in a stored position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 ,  2 , and  3  show a preferred embodiment of the invention, which is an aircraft  101  with a body  102 , a left wing  103 , and a right wing  104 . The aircraft is an airplane, that is, an aircraft that is lifted in flight by wings which may be fixed with respect to the rest of the aircraft while flying. 
     The term “wing” has been used by others to describe both wings of an airplane together, and is linked with the terms “monoplane” (one wing), “biplane” (two wings, one atop the other), “tandem wing” (two wings, one following the other), etc. It should be clearly understood that the use of the term “wings” in describing and claiming the invention does not limit the invention to biplanes, tandem wing aircraft, etc. 
     It should also be clearly understood that while the wings are said to be “fixed”, this term, as is commonly understood by those skilled in the art, as in “fixed-wing aircraft,” does not preclude the moving of the wings or parts thereof in flight for control, efficiency, etc. The wings of the Wright brothers&#39; airplane of 1903 are fixed in this sense, although warping the wings was an essential feature to control the aircraft. The F-14 Tomcat is also considered a “fixed-wing” aircraft, although its wings swing in or out for best efficiency at different speeds. These and similar motions still allow, by common understanding, the airplane wings to be accurately described as “fixed”. 
     Furthermore, the invention is applicable to any aircraft with fixed wings. An alternate embodiment of the aircraft (not shown) could be equipped with wings that could be fixed for flight and also a rotor to provide lift under certain conditions of flight, such as for hovering or flying at very low speeds. In such a case the aircraft might be classified as a helicopter or auto-gyro, but the aircraft could include wings that could be fixed for lifting the aircraft in flight and could therefore include the invention. 
     The wings  103 ,  104  of the aircraft  101  are also of rigid material, in that they are made of metal, carbon-fiber-plastic composite or similar, relatively stiff material. Such wings are distinguished from wings covered with relatively flexible fabric, which were used by the Wright brothers and continue to be used for some low-speed aircraft. While it is relatively easy to fold wings covered with flexible fabric, wings of rigid material have advantages in structural efficiency, in holding an airfoil shape at higher speeds, in resistance to puncturing, snagging and tearing, and in overall durability. Providing wings of rigid material which fold simply and effectively is an aspect of this embodiment. 
     An airplane typically has a tail, including horizontal aerodynamic surfaces distinct from the wings and used to provide stability in flight. The aircraft  101  has a vertical tail  107 . The action of a horizontal is incorporated into the wings  103 ,  104 , by size and design, especially by extending the wings rearward toward the rear of the body  102 . The aircraft  101  has no horizontal tail, which is preferred, in that the horizontal surface area that provides this stabilizing function is incorporated into the wings  103 ,  104  and so this area swings and folds with them to reduce the size of the aircraft. 
     An airplane typically has control surfaces, that is, moveable surfaces on the aircraft, which may be directed for maneuvering the airplane as it flies through the air and which may include: ailerons hinged along the trailing edges of the wings, elevators hinged along the trailing edges of the horizontal tail, and a rudder hinged along the trailing edge of the vertical tail. Ailerons can roll the aircraft left and right, elevators can pitch the aircraft up and down, and the rudder can yaw the aircraft left and right. 
     Alternately, functions of these control surfaces may be combined, such as by the use of elevons for the functions of both elevators and ailerons, especially in the case of an aircraft without a horizontal tail.  FIGS. 1 ,  2 , and  3  show a left elevon  113  as a part of the left wing  103  and attached by a left hinge  123  to the rest of that wing and also a right elevon  114  as a part of the right wing  104  and attached by a right hinge  124  to the rest of that wing. Each hinge  123 ,  124  is a joint between the respective elevon  113 ,  114  and the remainder of the wing  103 ,  104  which allows the elevon to move, that is to fold, along the hinge relative to the rest of the wing, as is well known to those skilled in the art. 
     The left wing  103  can swing using a left pivot joint  133 , and the right wing  104  can swing using a right pivot joint  134 . Each pivot joint  133 ,  134  is located near the leading edge and the inboard end of the respective wing  103 ,  104 , referring to the wing as it is positioned for flight. The wings  103 ,  104  remain essentially horizontal as they swing, although a small angle of a few degrees may be useful to allow them to overlap one another. A small amount of vertical motion in each pivot joint  133 ,  134  may be used to allow wings at the same level in flight to overlap one another. 
     As the wings  103 ,  104  swing from their flight position toward their stored position, the left hinge  123  crosses over the right wing  104  and the right hinge  124  crosses over the left wing  103 . The hinges  123 ,  124  and elevons  113 ,  114  pass under an upper part  105  of the body  102  and the tail  107  and over a lower part  106  of the body. 
     The left wing  103  overlaps the right wing  104 , in plan, that is when viewed from above or in the top view, in the stored position, as shown in  FIGS. 1 and 2 . This overlap significantly reduces the solid area of the aircraft  101  in plan with the wings in the stored position and decreases the effects of winds on the aircraft while not in flight. This overlapping of the wings also places both elevons  113 ,  114  in positions above free space, where both can be folded to vertical positions using the hinges  123 ,  124 . 
     In this embodiment, the hinges  123 ,  124  are used both for control in flight and for moving the wing, especially the elevons  113 ,  114 , from a position for flight to a position for storing or maneuvering the aircraft  101  when not in flight. When used to pitch the aircraft  101  up or down, the elevons  113 ,  114  both move in the same direction, either both downward or both upward. Both elevons  113 ,  114  move downward, that is, droop, for storage. For storage, the hinges  123 ,  124  droop the elevons  113  or  114  more than 60 degrees, that is fold the elevons sharply with respect to the rest of the wings  103 ,  104 , to essentially vertical positions which eliminate a majority of the plan area for the elevons. 
     Each of the elevons  113 ,  114  fully spans the wing  103 ,  104  to which it is hinged, so that folding the elevons reduces the whole width of the stored wings in plan. Thus, the maximum width of the stored wings  103 ,  104  is reduced and the maximum width of the aircraft in this configuration is reduced, with the several benefits described. 
     The upper part of the body  105  covers part of the wings  103 ,  104 , when stored, which is shown in  FIGS. 1 ,  2 , and  3 , especially in  FIG. 3 . That is, the upper of the body  105  covers the remainder of the upper stored wing, the right wing,  104 , which in turn covers, in part, the remainder of the lower stored wing, the left wing  103 . The lower part of the body  106  is covered by the wings  103 ,  104 , when stored, which is shown especially in  FIG. 3 , and which may protect the wings from debris from the ground. 
     For an aircraft for use at sea, the lower part of the body  106  may protect the wings  103 ,  104  from waves and even help to provide floatation for the aircraft for emergency landing or for amphibious operation. The elevons  113 ,  114 , when drooped help to shed water from the wings  103 ,  104 , and when the elevons are folded close to the lower part of the body  106 , they afford little space to catch water from below. 
     The aircraft  101  has wheels  108 A,  108 B,  108 C for supporting the aircraft while on the ground. The main wheels  108 A,  108 B are partly enclosed by the elevons  113 ,  114  in their stored position. The nose wheel  108 C may be steered for aiding the maneuvering of the aircraft while on the ground. The aircraft  101  has a canopy  109  for entry and egress of any occupants and for visibility while piloting and maneuvering the aircraft. The aircraft is also provided with a propulsion device which in this embodiment a fan  110 , such as part of a turbofan engine or, alternately, a fan connected to a piston engine. The wings  103 ,  104  while in the stored position allow the fan  110  to be operated for maneuvering the aircraft on the ground or water. 
     A transformation in the aircraft  101  from the flight position for the wings  103 ,  104  shown in  FIG. 1  to the stored position shown in  FIGS. 1  (dotted lines),  2 , and  3  is, for the embodiment show therein, as follows. The left and right elevons  113 ,  114  each assume an essentially flat position with respect to the rest of the left and right wings  103 ,  104 , respectively. The left and right wings  103 ,  104  swing using left and right pivots  133 ,  134 , respectively, inward, with the right wing  104  above and overlapping the left wing  103 , and both wings, especially the elevons  113 ,  114 , passing through the body  102 , that is below a part of the body  105  and above another part of the body  106 . With left hinge  123  positioned along the right side of the body, and right hinge  124  positioned near the left side of the body, the elevons  113 ,  114  fold sharply downward, or droop, which reduces the width of the aircraft  101  for maneuvering and otherwise operating the aircraft when not in flight and for storage of the aircraft. This process may be reversed for unfolding the wings  103 ,  104  for flight. 
     In operation of the aircraft  101 , the swinging and folding sequence described above might be performed near the end of the runway, just after landing. The reverse, or unfolding and swinging sequence also might be performed near the end of the runway, just before engine testing. Thus, the aircraft  101  can become and remain relatively compact, especially in width, while maneuvering and otherwise operating on the ground, especially in going to and from its hangar or parking area. 
     In another preferred embodiment of the invention shown in  FIG. 4 , an aircraft  401  has a body  402  with a substantial width for obtaining lift, a first wing  403 , and a second wing  404 . The first wing  403  includes a control surface  413 , a folding joint  423  for moving the control surface relative to the rest of the wing, and a swinging joint  433  for moving the wing relative to the body  402 . The second wing  404  includes a control surface  414 , a folding joint  424  for moving the control surface relative to the rest of the wing, and a swinging joint  434  for moving the wing relative to the body  402 . 
     The first wing  403  is shown in an outstretched in a position for flight and the second wing  404  is shown in a folded position for storage. In this embodiment, the swinging joints  433 ,  434  are located near the folding joints  423 ,  424 , that is near the folding edges of the wings  403 ,  404 . The wings  403 ,  404  swing using the joints  433 ,  434  from a position for flight forward to a position for storage, and the control surfaces  413 ,  414  fold upward from a position for flight to a folded position for storage. 
     The aircraft  401  has a vertical tail  407 , which supports a propeller  410  that is a propulsion device for this embodiment. The wings  403 ,  404  in the stored position are lower than the propeller  410  in height and allow the propeller to continue to be operated, if desired. The propeller  410  is in part enclosed by the control surfaces  413 ,  414  when they are folded upwards. Since the control surfaces  413 ,  414  fold upward and the propulsion device is above the rest of the wings  403 ,  404 , the wings may be just above the wheels so that the canopy  409  allows visibility towards the rear. 
     According to these examples, there are many other embodiments which may be constructed according to the invention which will be clear to those skilled in the art.