Abstract:
A toy model aircraft aims to imitate V-22 Osprey with high emulation by being providing with flight characteristics of V-22 Osprey at a shrunk size of a toy specification. The model aircraft of the invention includes a fuselage, two fixed wings extended outwards from two sides of the fuselage and a tail wing at the tail of the fuselage. Each fixed wing includes a propeller engine installed at a distal end thereof and a rotor. The two rotors of the propeller engines rotating in opposite directions, and the propeller engines are coupled to form an integrated body through a rotary axle mechanism connecting to the wings. The fuselage holds a rotary axle driving means to drive the rotary axle mechanism to rotate and the propeller engines at two ends of the rotary axle mechanism are rotated concurrently between the vertical direction and horizontal direction.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a toy model aircraft and particularly to a VTOL (vertical take-off and landing) model aircraft having flight characteristics of helicopters and fixed-wing aircrafts. 
       BACKGROUND OF THE INVENTION 
       [0002]    Helicopter flies through air buoyancy generated by spinning of rotors. By changing the climbing power and tilted direction of the pulling force of the rotors, flight conditions of the helicopter can be maintained or altered. It provides many advantages such as vertical take-off and landing and hover in the air. But its cruising speed is lower and safety is less desirable. On the other hand, a fixed-wing aircraft flies through air buoyancy generated by a pressure difference formed by fast airflow passing through the upper and lower sides of airfoils. By changing the angles of ailerons, elevators or rudder, it has higher cruising speed and safety, but requires longer take-off distance and cannot hover in the air. In 1950s and 1960s, some companies in U.S., Canada and Europe developed tilted rotor aircrafts that have advantages of both helicopter and fixed-wing aircraft. Bell helicopter Co. and Boeing helicopter Co. developed a V-22 Osprey multi-purpose aircraft based on the multi-purpose VTOL aircraft R&amp;D plan (JVX plan) released by U.S. Department of Defense. It is one of few successful cases. 
         [0003]    V-22 Osprey also is called tiltrotor aircraft. It has two rotor tilt system assemblies which are turnable between the horizontal position and vertical position respectively installed on a tip of a wing which is similar to the airfoil of the fixed-wing aircraft. When the aircraft is in vertical take-off and landing, the rotor shaft is perpendicular to the ground surface. The aircraft flies like a transverse helicopter, and also can hover in the air, or fly forwards and backwards and crab. After it has reached a certain flying speed, the rotor shaft can be tilted forwards for ninety degrees in a horizontal condition, then the rotors can serve as a pulling propeller. In such a condition, the tilted rotor aircraft can fly in higher speed for longer distance like the fixed-wing aircraft. Thus the tilted rotor aircraft is a unique rotor aircraft with abilities of the helicopter that can perform vertical take-off and landing and hover in the air, and also with abilities of a turboprop that can fly in high cruising speed. 
         [0004]    Model aircraft has been developed following the real aircraft. As V-22 Osprey tiltrotor aircraft is a novel aircraft different from the conventional helicopter or fixed-wing aircraft, to modify V-22 Osprey to a model aircraft is a great challenge. At present, most model aircraft imitating V-22 Osprey merely imitates the profile or provides merely helicopter function. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention aims to provide a model aircraft with high emulation of V-22 Osprey that has same flight characteristics and can be shrunk to a toy specification. 
         [0006]    To be a real aircraft has to take many factors into account, such as: the fuselage must have space to accommodate a certain number of passengers or cargos, strong power to carry the loads to fly at high speed; the hull must be sealed and can withstand high pressure at high altitudes; the fuselage has to arrange complex electric control circuits and wiring, etc. However, a model aircraft does not need to consider those factors. Its casing and frame can be made of light PVC material, and the interior space can be fully used for installing electric or mechanical structures without carrying people or cargos. The engine power merely has to meet flight requirement. Considering the aforesaid differences of the real aircraft and model aircraft, the present invention provides a VTOL model aircraft that includes a fuselage, two fixed wings extended outwards from two sides of the fuselage, and a tail wing at the tail of the fuselage. Each of the two wings has a distal end equipped with a propeller engine. The two propeller engines respectively have a rotor rotating in opposite directions. The invention also has a rotary axle mechanism coupled with the wings in an integrated manner. The fuselage also holds a rotary axle driving means to drive the rotary axle mechanism and the propeller engines at two ends thereof to turn concurrently between the vertical direction and horizontal direction. 
         [0007]    The present invention employs the propeller engine to replace the turbine engine of the real aircraft. Because the model aircraft has a light weight and does not need to carry people or cargos, the propeller engine can provide adequate power to meet requirements of vertical take-off and landing and cruise. The fuselage of the model aircraft also does not need to leave space for accommodating people or cargos, hence the rotary axle driving means can be directly installed in the fuselage to directly drive the rotary axle mechanism and the two propeller engines to turn concurrently between the vertical direction and horizontal direction. The rotary axle mechanism is located transversely across the fuselage and wings, and provides mechanical and synchronous rotation of the propeller engines. Compared with the real aircraft that needs to install a rotor tilt system assembly on the distal end of the wing, the present invention provides a much simplified structure without complex electrical control synchronous mechanism. 
         [0008]    When the propeller engines of the model aircraft of the invention are in the vertical condition, the pitch of the propeller can be changed to allow the aircraft to perform vertical take-off and landing, and hover in the air. By changing the tilt direction of the rotor shaft and pitch, the aircraft can fly forwards and backwards, and crab. When the propeller engines are turned to the horizontal condition and the pitch of each propeller engine can be fixed at a selected value, cruising flight can be performed. Thus the model aircraft of the invention can function and operate like a real V22 Osprey aircraft to achieve high emulation. By incorporating the characteristics of the model aircraft, the invention simplifies the driving means of the real aircraft with a novel driving structure adapted to the size of the model aircraft at a shrunk size within 0.5 to 3 meters. Compared with the conventional model aircraft that partly imitates V22 Osprey aircraft or only imitates the profile of V22 Osprey aircraft, the present invention provides a full imitation design with substantial features and outstanding improvements. 
         [0009]    The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a schematic view of the model aircraft of the invention in a vertical take-off and landing or hover condition. 
           [0011]      FIG. 2  is a schematic view of the internal structure of the invention according to  FIG. 1 . 
           [0012]      FIG. 3  is a schematic view of the invention in a cruising flight condition. 
           [0013]      FIG. 4  is an enlarged view of a propeller engine. 
           [0014]      FIG. 5  is an exploded view of a propeller engine. 
           [0015]      FIG. 6  is an enlarged view of a rotary oblique plate. 
           [0016]      FIG. 7A  is a schematic view of the propeller engine according to  FIG. 1  in an operating condition. 
           [0017]      FIG. 7B  is a fragmentary enlarged view according to  FIG. 7A . 
           [0018]      FIG. 8A  is another fragmentary enlarged view according to  FIG. 7A . 
           [0019]      FIG. 8B  is a yet another fragmentary enlarged view according to  FIG. 7A . 
           [0020]      FIG. 9  is an exploded view according to  FIG. 3 . 
           [0021]      FIG. 10  is an enlarged view of the rotary axle mechanism. 
           [0022]      FIG. 11  is an exploded view of the linkage bar mechanism. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0023]    Please refer to  FIG. 1 , the present invention aims to provide a model aircraft which includes a fuselage  1 , two fixed wings  2  extended outwards from two sides of the fuselage  1  and a tail wing  3  located at the tail of the fuselage  1 . The two wings  2  respectively have a propeller engine  4  and  5  at a distal end with a rotor  42  and  52  coupled thereon rotating in opposite directions to offset rotation of the fuselage  1 . The aircraft also has wheels  6  respectively located at two sides of the bottom and below the prow. While the model aircraft is in vertical take-off and landing, or hover in the air, the propeller engines  4  and  5  are in a working condition. Seeing from the front side of the aircraft, the rotor rotates clockwise, and the other rotor  52  rotates counterclockwise as shown by the arrows in the drawings. Rotation of the rotors  42  and  52  generates an upward pulling force. By adjusting the rotating pitch of the rotors  42  and  52 , the pulling force can be adjusted. When the pulling force is greater than the gravity of the aircraft, the aircraft can take off vertically. When the pulling force is equal to the gravity the aircraft can hover in the air, and when the pulling force is smaller than the gravity the aircraft can be controlled to land steadily. 
         [0024]    Refer to  FIG. 2  for the internal structure of the aircraft. The propeller engines  4  and  5  include respectively a rotary nacelle  41  and  51  with the rotor  42  and  52  at the front end. The rotary nacelles  41  and  51  hold a driving mechanism and a pitch control means of the rotors  42  and  52 , and are coupled to form an integrated body through a rotary axle mechanism  8  connected to the wings  2 . The rotary axle mechanism  8  transversely stretches over the fuselage  1  which holds a rotary axle driving means  9  to drive the rotary axle mechanism  8  to rotate so that the propeller engines  4  and  5  at the two ends thereof can be turned concurrently between the vertical direction and horizontal direction. The arrows in the drawings indicate that the propeller engines  4  and  5  are rotated from the vertical direction to the horizontal direction. 
         [0025]    When the propeller engines  4  and  5  are rotated to the horizontal direction as shown in  FIG. 3 , the aircraft is in a cruising flight condition, and the rotors  42  and  52  are latched at a selected pitch. The pulling force generated by the rotation is changed to forward thrust force to drive the aircraft to fly in the cruising flight condition. In such a condition, like an ordinary fixed-wing model aircraft, flight condition is controlled through ailerons, an elevator and rudders. As shown in the drawings, an aileron  21  is located at the rear edge of the fixed wing  2  to control transverse manipulation of the aircraft. The tail wing  3  includes a horizontal tail  31  and vertical tails  32  at two ends of the horizontal tail  31 . The horizontal tail  31  has an elevator  311  at an upper rear edge. The two vertical tails  32  respectively have a rudder  321  at a rear edge. The aileron  21 , elevator  311  and rudder  321  are controlled respectively through independent cruising control steering engines  73 ,  72  and  71 . 
         [0026]    In addition to the two types of flight conditions mentioned above, the propeller engines  4  and  5  also can be rotated to a selected angle relative to the vertical direction, such as between 10° and 80° in the forward or reverse direction so that desired pitch of the rotors  42  and  52  can be adjusted to generate desirable pulling force to realize forward or backward flying of the aircraft. 
         [0027]    Please refer to  FIGS. 4 and 5  for the detailed structure of the propeller engine, the propeller engine  5  is taken as an example. It includes the rotary nacelle  51  and rotor  52  at the front end of the rotary nacelle  51 . The rotor  52  include a central hub  521 , three rotor blades  524  and three blade clips  523  which are coupled with the central hub  521  through three radial rotary shafts  522  which are evenly spaced from each other on the circumference of the central hub  521 . Each blade clip  523  has a front end clamping one rotor blade  524  and is turnable about the radial rotary shaft  522  to alter the pitch of the rotor  52 . The central hub  521  also has a rotor shaft  513  extended to the rotary nacelle  51 . The driving mechanism includes a motor  511  and a gear set  512 , and is installed on a distal end of the rotor shaft  513 . The pitch control means includes a pitch control steering engine  514 , a rotary oblique plate  53  and a plurality of pulling rods located in the middle of the rotor shaft  513 . 
         [0028]    Referring to  FIG. 6 , the rotary oblique plate  53  includes an upper plate  532  and a lower plate  531  that are interposed by a coil spring  533  to connect with the rotor shaft  513  through a spherical hinge  534  in an inclined manner. The coil spring  533  is wedged among the upper plate  532 , lower plate  531  and spherical hinge  534 . The lower plate  531  has two turnable nodes  535  on the periphery at the same straight line and a tilt control node  536  perpendicular to the straight line where the turnable nodes  535  are located. The turnable nodes  535  are held on a rotary seat consisting of two bracing plates  541 . The tilt control node  536  is connected to the pitch control steering engine  514  through a lower pulling rod  542 . The upper plate  532  has pitch control nodes  537  on the circumference evenly spaced from one another at a number mating the rotor blades. The blade clip  523  has an eccentric control end  526  on one side. The pitch control nodes  537  and the eccentric control end  526  are connected through upper pulling rods  543  with a mating number. Refer to  FIG. 7A  for the assembly structure and  FIG. 7B  for the coupling structure after rotated. 
         [0029]    Refer to  FIG. 7A  for the operation principle of the propeller engine. The motor  511  drives the rotor shaft  513  to rotate through the gear set  512 , and the rotor shaft  513  further drives the three rotor blades  524  at the front end thereof to rotate to provide power for take-off, landing, hover and cruising of the aircraft. When the propeller engines  4  and  5  are not in the horizontal condition, i.e. during take-off, landing, forward or backward fly or crab, the pitch of the propeller engines  4  and  5  has to be changed to adjust the pulling force of the engines for the aircraft to balance the gravity thereof and to alter the flight condition. Alteration of the pitch of the propeller engines is controlled through the pitch control steering engine  514  as shown in  FIG. 7A . The pitch control steering engine  514  pulls the lower plate  531  braced by the bracing plate  541  through the lower pulling rod  542  as shown in  FIG. 8A . The lower plate  531  is tilted to drive the upper plate  532  to tilt also, and the upper plate  532  pulls the eccentric control end  526  on the one side of the blade clip  523  through the upper pulling rod  543  to change the pitch of the rotor blade  524  clamped by the blade clip  523 . When the propeller engines  4  and  5  are in the horizontal condition, i.e. the aircraft is in the cruising flight condition, the pitch control steering engine  514  controls the pitch of the rotor blade  524  at a selected value without changing. 
         [0030]    To ensure that the upper plate  532  is tilted upwards only in one direction, the invention further provides a positioning node  538  on the circumference of the upper plate  532  corresponding to the tilt control node  536  of the lower plate. The positioning node  538  is coupled on the rotor shaft  513  through an anchor seat turnable synchronously with the rotor shaft  513 . The anchor seat includes a coupling member  544  and a holding clip  545  that are coupled in a turnable manner. The assembled structure is shown in  FIG. 8B . The anchor seat and the lower pulling rod  542  are located on the same plane. The anchor seat confines the upper plate  532  from tilting to the left and right sides. 
         [0031]    Refer to  FIG. 9  for the exploded view of the invention. The fuselage  1  includes a main body consisting of an upper structure  13 , a middle structure  14  and a lower structure  15 . The main body has a front end coupled with a prow casing  11  through a front frame  12 , and a rear end coupled with the tail wing  3  through a rear frame  16 . The lower structure  15  has a battery box  18  with a lid  17 . The prow casing  11  holds a wireless receiving module  19  and its related circuit structures. The rotary axle mechanism  8  and rotary axle driving means  9  are installed on the middle structure  14 . Detailed structure can be seen in  FIG. 10 . The rotary axle mechanism  8  includes a rotary axle  81  transversely running through the two fixed wings  2 , a gear set  82  in the middle mating the rotary axle driving means  9 , and a bracing tube  84  to support rotation of the rotary axle  81 . The rotary axle  81  has two bearings  85  at two ends. The gear set  82  has a potentiometer  83  located thereon to measure turning angle of the rotary axle  81 . When changing the angle of the propeller engines  4  and  5  is needed, the rotary axle driving means  9  drives a screw  91  to rotate, then the screw  91  also drives the rotary axle  81  to rotate through the gear set  82 , so that the rotation angle of the propeller engines  4  and  5  coupled on two ends of the rotary axle  81  can be adjusted. The potentiometer  83  can accurately measure the rotation angle of the rotary axle  81 . The measured rotation angle is fed back to a control circuit to control the rotary axle driving means  9  to precisely position the rotation angle of the propeller engines  4  and  5 . 
         [0032]    The cruising control steering engines  73 ,  72  and  71  are connected to the aileron  21 , elevator  311  and rudder  321  through a linkage bar mechanism shown in  FIG. 11 . The linkage bar mechanism includes a swing bar  74 , an extended pulling rod  75  and a clip sheet  76 . The extended pulling rod  75  has two ends, one end is coupled with the clip sheet  76  and another end is coupled with the swing bar  74  through spherical hinges. The swing bar  74  has another end connected to the cruising control steering engine. The clip sheet  76  is connected to the aileron  21 , elevator  311  or rudder  321 . The aforesaid structure controls vertical take-off and landing and veer of the aircraft during cruising flight.