VTOL Aircraft Yaw Control via Thrust Vectoring and Coaxial Propellers
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Solution Overview
Problem
Existing hybrid tail-sitter aircraft face instability in hover, sensitivity to wind gusts, and yaw control issues due to high aspect ratio wings and complex control surface configurations, which limit their practicality and safety for various applications.
Innovation Solution
Aircraft design featuring coaxial counter-rotating propellers, elevons for pitch and roll control, and a thrust-vectoring system with fixed fins for yaw control, reducing the number of control surfaces and eliminating the need for bulky fuselage and rudders, allowing for stable operation and efficient use in cluttered environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high aspect ratio wings are used, then lift efficiency is improved, but gust sensitivity and stability deteriorate
Solution Approach 1:
The patent implements a dynamic control system with multiple independently controlled rotors that can adjust their rotational speeds in real-time. This dynamic adjustment allows the aircraft to maintain stability in hover by compensating for gusts and disturbances, resolving the contradiction between using high aspect ratio wings for lift efficiency and maintaining hover stability.
Solution Approach 2:
The control system changes operational parameters (rotor speeds) to maintain stability. By independently varying the rotational speed of each rotor, the system can counteract gust-induced disturbances and maintain stable hover despite using high aspect ratio wings that are inherently more gust-sensitive.
2Ease of operation
If complex control surface configurations are used, then control authority is improved, but device complexity increases
Solution Approach 1:
The patent extracts the yaw control function from traditional complex control surfaces (rudders, differential tail rotor) and implements it through a simplified thrust-vectoring system using fixed fins combined with differential thrust from the main rotors. This reduces control surface complexity while maintaining adequate control authority.
Solution Approach 2:
The main rotors serve multiple functions: they provide lift, enable pitch and roll control through differential speed adjustment, and contribute to yaw control through coordinated differential thrust. This multi-functionality reduces the need for separate complex control surfaces, simplifying the overall control system.
3Stability of the object's composition
If bulky fuselage and rudders are used, then yaw stability is improved, but weight and complexity increase
Solution Approach 1:
The patent extracts the yaw stability function from the traditional bulky fuselage and rudder configuration and implements it through a compact thrust-vectoring system using fixed fins positioned in the slipstream. This approach provides adequate yaw stability without the weight and complexity of traditional solutions.
Solution Approach 2:
The patent replaces the mechanical rudder system with a thrust-vectoring approach where differential rotor thrust provides yaw control authority. This substitution eliminates the need for large moving rudder surfaces and complex hinge mechanisms, reducing weight and complexity while maintaining yaw stability.
4Device complexity
If single propeller configuration is used, then simplicity is improved, but yaw control capability deteriorates
Solution Approach 1:
The patent segments the propulsion system into multiple independently controlled rotors instead of using a single propeller. This segmentation enables differential thrust control, providing yaw authority while maintaining relative simplicity in the overall configuration. The fixed fins work in conjunction with the segmented propulsion to enhance yaw control without requiring complex movable control surfaces.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enhances stability and control during hover and vertical takeoff/landing, reduces weight and complexity, and enables safe operation in moderate winds and cluttered spaces, making it suitable for diverse applications including urban and indoor use.
Implementation Method 1
coaxial counter-rotating propellers
Implementation Method 2
The two distant motors and propellers help to increase roll-inertia for increased roll stability
Implementation Method 3
The single slipstream induces yawing moment as the slipstream strikes a vertical stabilizer
Implementation Method 4
elevons for pitch and roll control
Implementation Method 5
Elevons are used instead of ailerons+an elevator, which reduces the total number of control surfaces
Implementation Method 6
a thrust-vectoring system with fixed fins for yaw control
Implementation Method 7
The thruster (2) rotates about the hinge axis (116) to vector thrust for aircraft yaw control
Implementation Method 8
The thruster (2) rotates about the hinge axis (116) to vector thrust for aircraft yaw control
Implementation Method 9
The mount (8) has at least one thruster (2) attached. The thruster (2) rotates about the hinge axis (116)
Data Source
AI summary
An unmanned aircraft capable of vertical takeoff, vertical landing, and/or flight in a hovering orientation is presented; its fixed-wing is positively-swept and of low aspect-ratio with suitable airfoils. The unmanned aircraft includes a thruster comprising two contra-rotating motors and propellers forward of the fixed-wing's leading-edge and a rudderless fin aft of the center-of-mass, all of which lie on the aircraft's plane-of-symmetry. Two elevons provide pitch and roll control. The unmanned aircraft can stand upright on its feet.A control system for aircraft with at least one wing is also presented. The control system includes a mount and attached thruster which lie on the plane-of-symmetry forward of the fixed-wing's leading-edge. A hinge axis approximately perpendicular to the aircraft's horizontal plane passes through the mount. The thruster rotates about the hinge axis for aircraft yaw control.