Trailing-Rotor Fixed Wing Layout for Stall Recovery Control
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Solution Overview
Problem
Existing aircraft designs, particularly those with tilt rotors, fail to efficiently transition between hover and cruise positions, leading to instability and control issues during stall out, and existing aircraft designs have tilt wings, fail to efficiently transition between cruise position and hover position, leading to instability and control issues during stall out.
Innovation Solution
Aircraft with a forward swept and fixed wing, equipped with trailing edge mounted tilt rotors and a T-tail configuration, which maintains control and stability during stall out by utilizing a canard and T-tail configuration, enhancing stability and control during high-speed flight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If tilt rotors are mounted on the trailing edge of a fixed wing, then the aircraft can transition between hover and cruise positions, but the aircraft experiences instability and control issues during stall out
Solution Approach 1:
The horizontal tail is divided into two separate surfaces: a conventional horizontal stabilizer and a T-tail horizontal stabilizer. This segmentation allows each surface to perform specific functions during different flight phases, with the T-tail providing dedicated stall recovery control independent of the main wing and canard
Solution Approach 2:
The T-tail configuration positions the horizontal stabilizer in a higher vertical dimension, above the rotor downwash region. This spatial repositioning allows the tail to maintain aerodynamic effectiveness during hover and transition phases when it would otherwise be obscured by rotor wake turbulence
2Device complexity
If a conventional horizontal tail is used, then the structure is simpler, but the aircraft loses control authority during deep stall conditions
Solution Approach 1:
The T-tail horizontal stabilizer acts as an intermediary control surface that can independently generate pitching moments to recover from deep stall conditions. When the canard and main wing are stalled and unresponsive, the T-tail provides a direct aerodynamic lever arm to restore controlled flight
Solution Approach 2:
The asymmetric placement of the T-tail above the rotor disk creates differential aerodynamic effects during various flight phases. During hover, the tail operates in clean airflow above the downwash, while during forward flight, it provides enhanced stall recovery authority through its elevated position
3Volume of moving object
If the horizontal tail is positioned low, then the structure is more compact, but the tail enters the rotor wake and loses effectiveness
Solution Approach 1:
The horizontal tail is repositioned from the lateral dimension (low vs high placement) to the vertical dimension (above the rotor disk). This dimensional change allows the tail to escape the rotor wake region while maintaining structural integration with the fuselage
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 configuration improves stability and control during stall out and high-speed flight, allowing for safer and more efficient transitions between vertical takeoff and landing, and forward flight, with reduced drag and increased flight range.
Implementation Method 1
The horizontal tail surfaces are positioned above the rotor wake to improve stability and control during stall out
Implementation Method 2
if some or all of the horizontal lift surfaces of the aircraft were to stall out
Implementation Method 3
Aircraft with a forward swept and fixed wing, equipped with trailing edge mounted tilt rotors
Implementation Method 4
trailing edge mounted tilt rotors and a T-tail configuration, which maintains control and stability during stall out
Data Source
AI summary
An aircraft that includes a canard having a leading edge and a trailing edge, a forward swept and fixed wing having a trailing edge, and a plurality of tilt rotor submodules, a dovetail, and a T-tail. The plurality of tilt rotor submodules are coupled to the trailing edge of the forward swept and fixed wing. The dovetail is attached to an underside of a fuselage. The T-tail is located above the dovetail. A horizontal plane of the T-tail is at a height that is higher than a horizonal plane of the forward swept and fixed wing.