VTOL Air Vehicle With Fixed-Inclined Rotors and a Rudder Vane

This paper describes a vertical take off and landing (VTOL) aircraft equipped with a rotor obliquely fixed to the wing and a control surface that changes the direction of the slipstream of the propeller. Conventional VTOL aircraft, such as lift-cruise or tilt rotor, show either increased drag and weight, resulting in reduced efficiency and payload capacity, or added mechanical complexity accompanied by sophisticated control requirements. Unlike other conventional VTOL aircraft, this vehicle achieves a stable transition between fixed-wing and rotary-wing modes simply by changing the pitch attitude of the aircraft. As the rotor is mounted at an inclined angle, it can control the pitch not only during hovering but also during horizontal flight by using differential thrust between the front and rear propulsion. Moreover, the roll angle can be controlled by using differential thrusts between the left and right thrusts. Additionally, this aircraft achieves yaw axis control by changing the direction of the rotor's slipstream. The control surface that adjusts the direction of the slipstream is termed the “rudder vane,” which is expected to provide rapid yaw response during hovering and naturally enhance directional stability during horizontal flight. Overall, this design promises improved energy efficiency, reduced mechanical and software complexity, and enhanced maneuverability, making the vehicle particularly well suited to demanding real-world operational environments. In this paper, mathematical modeling of a fixed-tilt rotor VTOL aircraft equipped with a rudder vane is performed, and a control law for the aircraft is designed and validated via flight tests.