Ultralight coaxial rotor aircraft

Abstract

An ultralight coaxial dual rotor helicopter having a substantially L shaped frame. Attached to the back of the frame is a vertical shaft engine, and a pair of yaw paddles for controlling yaw of the craft. The drive shaft connects to a belt drive at the top of the frame, which transmits the engine power to a transmission and coaxial drive gear for driving the rotors. Crank actuators are provided for tilting the rotor axis to control the pitch and roll of the craft. A pilot seat and ballast tank are attached to the front of the frame. The ballast tank may be filled with a volume of water to balance the craft for the weight of the pilot. The fuel tank is located behind the pilot seat on the centerline of the helicopter, such that as fuel is used and the weight of fuel in the tank changes, the balance of the craft will not be affected.

1 . An ultralight coaxial rotorcraft, comprising: 
 an airframe,    a coaxial rotor set attached to the airframe,    a prime-mover operatively coupled to the rotor set,    a control system, further comprising:    a hand grip rotatably, tiltably, connected to the airframe,    a rotor thrust control,    wherein movement of the handgrip about a yaw axis gives a yaw attitude control input to the control system, and movement about a roll axis gives a roll attitude control input, and movement about a pitch axis gives a pitch control input, whereby control of rotorcraft attitude in pitch roll and yaw is facilitated.    
   
   
       2 . The ultralight coaxial rotorcraft of  claim 1 , wherein the coaxial rotorcraft is configured to provide a pitch and a roll control by moving a center of gravity of the rotorcraft with respect to a rotor thrust vector.  
   
   
       3 . The ultralight coaxial rotorcraft of  claim 1 , wherein the airframe comprises a rigid vertical portion and a forwardly extending boom.  
   
   
       4 . The ultralight coaxial rotorcraft of  claim 3 , wherein the handgrip is carried by a handlebar carried by a tiltable member carried by the forwardly extending boom.  
   
   
       5 . The ultralight coaxial rotorcraft of  claim 3 , further comprising a seat attached to the rigid vertical portion and to the forwardly extending boom.  
   
   
       6 . The ultralight coaxial rotorcraft of  claim 1 , wherein the prime-mover comprises a four stroke internal combustion engine.  
   
   
       7 . The ultralight coaxial rotorcraft of  claim 6 , wherein the engine is mounted so that an output shaft rotates about a vertical axis.  
   
   
       8 . The ultralight coaxial rotorcraft of  claim 1 , wherein the prime-mover is coupled to the rotors through pulleys connected by a continuous belt, and wherein the pulleys can be of different size whereby a shaft speed reduction is facilitated.  
   
   
       9 . The ultralight coaxial rotorcraft of  claim 1 , further comprising a hydraulic actuator operatively coupled to the rotor and to the control system.  
   
   
       10 . A rotorcraft, comprising: 
 a rotor controllable to provide pitch and roll attitude control;    a yaw attitude control apparatus;    a control system comprising a handlebar yoke having a movable and turnable handlebar, where moving the handlebar in a fore-and-aft direction controls pitch attitude, and moving the handlebar generally side-to-side in port and starboard directions controls roll attitude, and rotating the handlebar about a generally vertical axis controls yaw attitude.    
   
   
       11 . The rotorcraft of  claim 10 , further comprising a rotatable handgrip, wherein a magnitude of thrust from the rotor is controlled by the rotatable handgrip.  
   
   
       12 . The rotorcraft of  claim 11 , further comprising a prime mover operatively coupled to the rotor and a throttle connection between the rotatable handgrip and the prime-mover, whereby power to the rotor from the prime mover is variable by actuation of the handgrip.  
   
   
       13 . The rotorcraft of  claim 12 , wherein the throttle connection between the rotatable handgrip and the prime mover comprises a cable.  
   
   
       14 . The rotorcraft of  claim 10 , wherein the connection between the handlebar control and the rotor comprises a pair of links which when moved in tandem provide pitch attitude control input and when moved differentially provide roll attitude control.  
   
   
       15 . A rotorcraft, comprising: 
 an airframe;    a rotor operatively coupled to the airframe;    a control system, further comprising a handlebar which is pivotably connected to the airframe at a base connection, and which tipable fore and aft and port and starboard about the base connection, tipping the handlebar fore and aft provides a pitch attitude control input and tipping the handlebar port and starboard provides a roll attitude control input.    
   
   
       16 . The rotorcraft of  claim 15 , wherein the handlebar is rotatable about an axis extending through a central point on the handlebar and substantially through the base connection, and wherein rotation of the handlebar about said axis provides a yaw attitude control input.  
   
   
       17 . The rotorcraft of  claim 15 , wherein the handlebar control further comprises a rotatable handgrip, and wherein rotation of the handgrip provides a rotor thrust vector magnitude control input.  
   
   
       18 . An aircraft control system configured for controlling the attitude of an airframe of the aircraft, comprising; 
 a stem pivotally connected to the airframe so as to be tipable fore and aft and port and starboard,    a handlebar rotatably carried by the stem,    a pitch attitude control input being obtainable by tipping the handlebar and stem fore and aft, and a roll attitude control input being obtainable by tipping the handlebar and stem port and starboard, and a yaw attitude control being obtainable by rotating the handlebar about a yaw axis.    
   
   
       19 . The aircraft of  claim 18 , wherein the control system further comprises a twist-grip handgrip, which is rotatable with respect to the handlebar, and wherein a trust force reacting on the airframe can be varied in magnitude by rotation of the handgrip.  
   
   
       20 . (canceled)  
   
   
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