Abstract:
A linkage device for a remote control model helicopter with coaxial and counter rotating double-propeller includes a servo steering engine operating system, a tail motor operating system and a receiver controlling device; the servo steering engine operating system includes a forward and backward servo steering engine operating unit and a leftward and rightward servo steering engine operating unit; the receiver controlling device is connected to both the servo steering engine operating system and the tail motor operating system and for controlling the forward and backward servo steering engine operating unit and the tail motor operating system to link simultaneously. Compared to a conventional three-channel or four-channel model helicopter, the model helicopter using the linkage device has better resistance to winds and meets requirements to fly fast against winds outdoors.

Description:
CROSS REFERENCE OF RELATED APPLICATION 
       [0001]    This is a U.S. National Stage under 35 USC 371 of the International Application PCT/CN2010/002183, filed Dec. 28, 2010. 
     
    
     BACKGROUND OF THE PRESENT INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The present invention relates to a linkage device for a model helicopter, and more particularly to a linkage device for a remote control model helicopter with coaxial and counter rotating double-propeller. 
         [0004]    2. Description of Related Arts 
         [0005]    The conventional remote control model helicopter with coaxial and counter rotating double-propeller mainly comprises a landing gear, a body, a receiver controlling device, a motor power transmitting device, a rotor lifting device, a flybar device and a forward and backward device. 
         [0006]    The forward and backward device of a conventional four-channel model helicopter is embodied as an operating unit of a forward and backward servo steering engine in a servo steering engine controlling system which is realized by a manner that the servo steering engine drives a servo steering engine joystick; that the servo steering engine joystick further drives a swashplate to tilt; and that the swashplate further drives a rotor head via a rotor connecting rod to force a rotating plane of a lower rotor to tilt forwardly or backwardly. However, the forward and backward device thereof has a disadvantage that, when the rotating plane of the lower rotor tilts forwardly and the helicopter flies forwardly, under the action of a centrifugal force of the flybar, the upper rotor would produce an opposite equal force tilting backwardly to counteract with the force driving the helicopter to fly forwardly; and vice versa. Thus this type of helicopter has relatively weak forces of flying forwardly and backwardly and is vulnerable to airflows; a strong wind may stop the helicopter. 
         [0007]    The forward and backward device of a conventional three-channel model helicopter is embodied as a tail motor operating system which is realized by a manner that a tail motor rotates positively and reversely to drive a screw propeller to rotate positively and reversely, so as to generate forces to lower or raise a head thereof. The conventional three-channel model helicopter also has the problem of the weak forces of flying forward and backward. Because the tail motor is related with power matching, an appearance and a center of gravity, a volume, a size and a weight thereof are strictly limited, and thus the tail motor has a small power and provides very small motive forces; moreover, under the action of the centrifugal forces of the flybar, the rotating plane of the upper rotor tilts opposite to a tilting direction of the body and a force of the tilting adequately counteracts with the force lowering or raising the head thereof generated by the positive and negative rotations of the tail motor, so that the body thereof is unable to effectively generate torque to lower or raise the head; and thus the conventional three-channel helicopter is unable to fly in outdoor winds. 
       SUMMARY OF THE PRESENT INVENTION 
       [0008]    An object of the present invention is to provide a linkage device for a remote control model helicopter with coaxial and counter rotating double-propeller having a good resistance to winds, so as to satisfy requirement for the model helicopter to fly fast against winds outdoors. 
         [0009]    In order to accomplish the above objects, the linkage device of the present invention adopts following technical solutions. The linkage device comprises a servo steering engine operating system, a tail motor operating system and a receiver controlling device. The servo steering engine operating system comprises a forward and backward servo steering engine operating unit and a leftward and rightward servo steering engine operating unit. The receiver controlling device is connected to both the servo steering engine operating system and the tail motor operating system and able to control the forward and backward servo steering engine operating unit and the tail motor operating system to link simultaneously. 
         [0010]    The receiver controlling device is for controlling the forward and backward servo steering engine operating unit and the tail motor operating system to link simultaneously to control the forward and backward servo steering engine operating unit and the tail motor operating system to act simultaneously when the model helicopter flies forwardly and backwardly. 
         [0011]    The forward and backward servo steering engine operating unit comprises a forward and backward servo steering engine, a servo steering engine joystick, a swashplate, a rotor head connecting rod, a rotor head and rotors. The forward and backward servo steering engine is installed on a body of the model helicopter; a first end of the servo steering engine joystick is installed on the forward and backward servo steering engine and a second end thereof is connected to the swashplate; a first end of the rotor end connecting rod is installed on the swashplate and a second end thereof is installed on the rotor head; the rotors are installed on the rotor head. The tail motor operating system comprises a tail motor frame, a tail motor, a screw propeller and tail motor fasteners. The tail motor frame is fixed on a back of the body; the tail motor is fixed on the tail motor frame via the tail motor fasteners; and the screw propeller is fixed on the tail motor. 
         [0012]    The tail motor operating system further comprises a tail motor manual switch connected to the receiver controlling device. 
         [0013]    The receiver controlling device comprises a radio frequency (RF) signal circuit, a micro controller unit (MCU) and a motor driving circuit, wherein the MCU is connected to the servo steering engine operating system; the motor driving circuit is connected to the tail motor operating system; after receiving a controlling instruction, the RF signal circuit is processed by the MCU and then sends controlling signals into the servo steering engine operating system and the motor driving circuit. 
         [0014]    The present invention combines a conventional three-channel model helicopter with a conventional four-channel model helicopter via the receiver controlling device, and controls a lower rotor to tilt via the forward and backward servo steering engine operating unit of the servo steering engine operating system to counteract with reaction forces of an upper rotor; meanwhile, the tail motor operating system receives an instruction of the receiver controlling device that the tail motor drives the screw propeller to rotate positively or reversely to generate an upward force or a downward force without restrictions which acts on the body of the helicopter to form and keep a relatively big angle tilting forwardly or backwardly, when rotating planes of the upper rotor and the lower rotor also form and keep an identically big angle, in such a manner that the upper rotor and the lower rotor rotate to generate a relatively big force pushing forwardly or backwardly to provide a relatively strong forwardly or backwardly driving force for the helicopter to reach effects of a strong resistance to winds and a fast flying speed, so as to satisfy needs of flying against the winds outdoors. 
         [0015]    These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a perspective view of a linkage device for a remote control model helicopter with coaxial and counter rotating double-propeller according to a preferred embodiment of the present invention. 
           [0017]      FIG. 2  is a block diagram of circuit principles of a receiver controlling device of  FIG. 1 . 
           [0018]      FIG. 3  is a sketch view of installing the linkage device according to the preferred embodiment of the present invention. 
       
    
    
       [0019]    In the drawings:  1 —forward and backward servo steering engine;  2 —tail motor;  3 —screw propeller;  4 —receiver controlling device;  5 —tail motor manual switch;  6 —RF signal circuit;  7 —MCU;  8 —motor driving circuit;  9 —servo steering engine joystick;  10 —swashplate;  11 —rotor head connecting rod;  12 —rotor head;  13 —rotor;  14 —tail motor frame;  15 —tail motor fastener;  16 —leftward and rightward servo steering engine. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]    Referring to  FIG. 1  of the drawings, according to a preferred embodiment of the present invention, a linkage device for a remote control model helicopter with coaxial and counter rotating double-propeller comprises a servo steering engine operating system (only a forward and backward servo steering engine  1  and a leftward and rightward servo steering engine  16  showed), a tail motor operating system (only a tail motor  2  and a screw propeller  3  showed) and a receiver controlling device  4 . The receiver controlling device  4  is respectively connected to the forward and backward servo steering engine  1 , the leftward and rightward servo steering engine  16  and the tail motor  2  via electric wires and able to control the forward and backward servo steering engine  1  and the tail motor  2  to link simultaneously to control the forward and backward servo steering engine operating unit and the tail motor operating system to act simultaneously when the helicopter flies forwardly and backwardly. The screw propeller  3  is installed on the tail motor  2 . A tail motor manual switch  5  is installed on the electric wires connecting the tail motor  2  and the receiver controlling device  4  to control whether the tail motor operating system accepts and executes acting instructions from the receiver controlling device  4 . 
         [0021]      FIG. 2  shows circuit principles of the receiver controlling device  4  which comprises a RF signal circuit  6 , an MCU  7  and a motor driving circuit  8 , wherein the MCU  7  is connected to the forward and backward servo steering engine  1  and the leftward and rightward servo steering engine  16 ; and the motor driving circuit  8  is connected to the tail motor  2 . After receiving a first controlling instruction of flying forwardly or backwardly, the RF signal circuit  6  is processed by the MCU  7  and sends two groups of controlling signals into the forward and backward servo steering engine  1  and the motor driving circuit  8 ; a first group comprises pulse position modulation (PPM) signals for controlling the forward and backward servo steering engine  1  to act according to the first controlling instruction of flying forwardly or backwardly; a second group comprises pulse width modulation (PWM) signals for synchronously controlling the motor driving circuit  8  to drive the tail motor  2  to act according to the first controlling instruction of flying forwardly or backwardly. Thereby it is realized that the forward and backward servo steering engine  1  and the tail motor  2  are linked simultaneously, so as to accomplish a purpose of improving performance in resisting winds. When the model helicopter flies indoors or without winds, the tail motor manual switch  5  can be turned off, when a signal route to reach the tail motor  2  is cut off and the tail motor  2  is idle, so as to satisfy needs of flying without winds. After receiving a second controlling instruction of flying leftwardly or rightwardly, the RF signal circuit  6  is processed by the MCU  7  and sends the first group of PPM signals into the leftward and rightward servo steering engine  16  to control the leftward and rightward servo steering engine  16  to act according to the second controlling instruction of flying leftwardly or rightwardly. 
         [0022]      FIG. 3  shows an installing structure of the linkage device of the present invention. The servo steering engine operating system is installed on an upper part of a body, comprising the forward and backward servo steering engine operating unit and the leftward and rightward servo steering engine operating unit which is provided at backside and not showed, wherein the forward and backward servo steering engine operating unit comprises the forward and backward servo steering engine  1 , a servo steering engine joystick  9 , a swashplate  10 , a rotor head connecting rod  11 , a rotor head  12  and rotors  13 . The forward and backward servo steering engine  1  is installed on the body; a first end of the servo steering engine joystick  9  is installed on the forward and backward servo steering engine  1  and a second end thereof is installed on the swashplate  10 ; a first end of the rotor end connecting rod  11  is installed on the swashplate  10  and a second end thereof is installed on the rotor head  12 ; the rotors  13  are installed on the rotor head  12 . The tail motor operating system, provided on a tail part of the body, comprises a tail motor frame  14 , a tail motor  2 , a screw propeller  3  and tail motor fasteners  15 . The tail motor frame  14  is fixed on a back part of the body; the tail motor  2  is fixed on the tail motor frame  14  via the tail motor fasteners  15 ; and the screw propeller  3  is fixed on the tail motor  2 . The receiver controlling device  4  is provided in a front part of the body. 
         [0023]    After receiving a synchronous controlling instruction of flying forwardly or backwardly, the receiver controlling device  4  sends synchronous action signals into the forward and backward servo steering engine  1  and the tail motor  2 , and then the forward and backward servo steering engine operating unit and the tail motor operating system act simultaneously. A specific process is as follows. The forward and backward servo steering engine  1  drives the servo steering engine joystick  9 ; the servo steering engine joystick  9  drives the swashplate  10  to tilt; and the swashplate  10  drives the rotor head  12  via a rotor head connecting rod  11  to force a rotating plane of a lower rotor  13  to tilt forwardly or backwardly. When the rotating plane of the lower rotor  13  tilts forwardly according to instructions, the tail motor  2  drives the screw propeller  3  to positively rotate synchronously to generate a downward force to lift the tail part of the helicopter and lower the head of the helicopter and instantly the helicopter gains force components tilting forwardly to fly forwardly; when the rotating plane of the lower rotor  13  tilts backwardly according to instructions, the tail motor  2  drives the screw propeller  3  to reversely rotate synchronously to generate an upward force to press the tail part of the helicopter downwardly and lift the head and instantly the helicopter gains force components tilting backwardly to fly backwardly. Thereby, even flying in a windy weather, the helicopter is protected from airflows. The tail motor manual switch  5  can be turned on and off according to practical needs to control whether the tail motor  2  is synchronously linked with the forward and backward servo steering engine  1 . When the tail motor manual switch  5  is turned off, the forward and backward servo steering engine  1  drives the rotating plane of the lower rotor  13  to tilt forwardly or backwardly under instructions, but the tail motor  2  is idle, so as to suit for flying indoors or without winds. Similarly, a tail motor circuit can be turned off via wireless instructions to realize flying without winds when the tail motor operating system and the forward and backward servo steering engine operating unit are unable to link simultaneously, i.e., the tail motor operating system is idle and the forward and backward servo steering engine operating unit acts. 
         [0024]    After receiving the synchronous controlling instruction of flying leftwardly or righwardly, the receiver controlling device  4  sends action signals to the leftward and rightward servo steering engine  16  and instantly the leftward and rightward servo steering engine operating unit acts to force the helicopter to fly leftwardly or rightwardly. 
         [0025]    In order to prove superior performance of the linkage device of the present invention, a testing and comparison experiment about resistance to winds is held between identical helicopter types of each conventional model helicopter with coaxial and counter rotating double-propeller on the market and a model helicopter with coaxial and counter rotating double-propeller using the linkage device of the present invention. Table 1 shows results thereof. 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
             
             
               
                   
                   
               
               
                   
                 flying tests of model helicopters against winds of each scale 
                   
               
             
          
           
               
                 350 
                   
                 scale 0 
                 scale 1 
                 scale 2 
                 scale 3 
                 scale 4 
                   
               
               
                 helicopter 
                 test 
                 status of the 
                 status of the 
                 status of the 
                 status of the 
                 status of the 
               
               
                 types 
                 frequency 
                 flight speed 
                 flight speed 
                 flight speed 
                 flight speed 
                 flight speed 
                 conclusion 
               
               
                   
               
               
                 350 two- 
                 5 
                 3 m/s 
                 0 m/s 
                 0 m/s 
                 0 m/s 
                 0 m/s 
                 suitable for flying 
               
               
                 channel 
                   
                 stable &amp; 
                 going with winds 
                 going with winds 
                 unable to take 
                 unable to rake 
                 indoors 
               
               
                 helicopter 
                   
                 controllable 
                 &amp; losing control 
                 &amp; losing control 
                 off 
                 off 
               
               
                 350 three- 
                 5 
                 6 m/s 
                 4 m/s 
                 2 m/s 
                 0 m/s 
                 0 m/s 
                 suitable for flying 
               
               
                 channel 
                   
                 stable &amp; 
                 stable &amp; 
                 bumpy &amp; hardly 
                 going with winds 
                 unable to take 
                 indoors or in outdoor 
               
               
                 helicopter 
                   
                 controllable 
                 controllable 
                 controllable 
                 &amp; losing control 
                 off 
                 breeze 
               
               
                 350 four- 
                 5 
                 7 m/s 
                 5 m/s 
                 3 m/s 
                 0 m/s 
                 0 m/s 
                 suitable for flying 
               
               
                 channel 
                   
                 stable &amp; 
                 stable &amp; 
                 bumpy &amp; 
                 going with winds 
                 unable to take 
                 indoors or in outdoor 
               
               
                 helicopter 
                   
                 controllable 
                 controllable 
                 controllable 
                 &amp; losing control 
                 off 
                 breeze 
               
               
                 350 helicopter 
                 5 
                 14 m/s 
                 12 m/s 
                 10 m/s 
                 8 m/s 
                 5 m/s 
                 suitable for flying 
               
               
                 using the 
                   
                 stable &amp; 
                 stable &amp; 
                 stable &amp; 
                 stable &amp; 
                 bumpy &amp; 
                 indoors or in outdoor 
               
               
                 present 
                   
                 controllable 
                 controllable 
                 controllable 
                 controllable 
                 controllable 
                 winds below scale 4 
               
               
                 invention 
               
               
                   
               
             
          
         
       
     
         [0026]    The results show that, in a condition of no winds, the model helicopter using the linkage device of the present invention flies faster than the conventional model helicopter; in a condition of winds below scale  4 , the model helicopter using the linkage device of the present invention flies faster than the conventional model helicopter and has better stability and controllability than the conventional model helicopter, especially in relatively strong winds of scale  3  to scale  4 , the conventional model helicopter totally lose control while the model helicopter using the linkage device is still able to fly against winds. 
         [0027]    One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting. 
         [0028]    It will thus be seen that the objects of the present invention have been fully and effectively accomplished. Its embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.