Ducted Fan Aerodynamic Features for Control Redundancy
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Solution Overview
Problem
Aircraft with ducted fans lack sufficient control authority and redundancy, particularly in modular and morphable air vehicles, which require advanced aerodynamic features to manage various flight configurations efficiently.
Innovation Solution
The ducted fan incorporates morphable leading edges, air dams, and movable vanes that can be asymmetrically or differentially deployed to adjust thrust vectors, providing additional control authority and redundancy by altering lift and drag characteristics based on flight conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ducted fans are used without additional aerodynamic features, then the device complexity is low, but the control authority and redundancy are insufficient
Solution Approach 1:
The duct is divided into multiple independent aerodynamic control surfaces (leading edge flaps, trailing edge flaps, ailerons, spoilers) that can be operated separately to provide differential control authority. Each surface segment can be independently actuated to achieve precise control moments while maintaining overall structural integrity.
Solution Approach 2:
The aerodynamic control surfaces are designed to be movable and adjustable during flight, allowing the duct to dynamically adapt its aerodynamic characteristics. The surfaces can be deflected to various angles to provide control authority across different flight regimes, transforming a static structure into a dynamic control system.
2Adaptability or versatility
If aerodynamic features are added to improve control authority, then the control options increase, but the manufacturing complexity increases
Solution Approach 1:
The aerodynamic control surfaces serve multiple functions: they provide roll control through ailerons, pitch control through elevator surfaces, and can act as spoilers for drag management. The same duct structure simultaneously provides thrust augmentation and aerodynamic control, reducing the need for separate control systems.
Solution Approach 2:
The control surfaces are designed with adjustable deflection angles and positions that can be optimized for different flight conditions. By changing the geometric parameters of the control surfaces (deflection angles, surface areas, positions), the duct can adapt its aerodynamic characteristics without requiring multiple physical components.
3Productivity
If the duct structure is simplified, then the ease of manufacture improves, but the efficiency in different flight modes decreases
Solution Approach 1:
The aerodynamic control surfaces are designed to be periodically adjusted during flight to optimize performance for different flight phases. The surfaces can be deflected to specific angles during takeoff, cruise, and landing phases, allowing the duct to periodically adapt its aerodynamic characteristics to match flight requirements.
Solution Approach 2:
Different portions of the duct are equipped with specialized aerodynamic features optimized for their specific locations and functions. The leading edge has flaps for lift control, the trailing edge has flaps for drag and lift control, and the sides have ailerons for roll control. Each local region has quality characteristics tailored to its aerodynamic role.
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
This configuration enhances control options and efficiency by optimizing thrust and drag for different flight modes, allowing the aircraft to hover, fly at low speeds, or high speeds with improved stability and maneuverability.
Implementation Method 1
the flow of inrush air across the curved throat generates lift in the direction of thrust of the ducted fan as a result of the Bernoulli relation
Implementation Method 2
the air dam extends from the surface of the duct leading edge portion and interrupts the flow of inrush air over the leading edge portion of the duct, reducing lift generated by the flow of inrush air
Implementation Method 3
A first vane and a second vane may be disposed within a flow of air moving from the ducted fan and may be actuated differentially to redirect the thrust vector
Data Source
AI summary
A ducted fan for an aircraft or other vehicle includes aerodynamic features to selectably move the thrust vector of the ducted fan from the axis of rotation of the ducted fan, providing additional and redundant control authority to a control system. The control system may apply the aerodynamic features asymmetrically about the circumference of the duct and may apply the aerodynamic features differentially among a plurality of ducted fans. The aerodynamic features may include a morphing leading edge portion, an air dam, vanes and trailing edge control surfaces.