Tiltrotor Active Wing Extensions for Structural Mode Damping
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Solution Overview
Problem
Tiltrotor aircraft face stability issues due to structural modes like pitch-plunge and whirling movements, which can be catastrophic, and existing passive damping systems are inefficient and add weight, reducing endurance.
Innovation Solution
A pylon assembly with a rotatable wing extension that remains in the slipstream of the proprotor, using a linkage arm or actuator to synchronize rotation with the rotor assembly, and a feedback loop system to oscillate the wing extension at a dampening frequency to stabilize the aircraft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If passive damping systems are added to dampen structural modes, then stability is improved, but weight increases and endurance decreases
Solution Approach 1:
The wing extension is made dynamically movable rather than fixed, allowing it to actively respond to and dampen structural modes through controlled movement, replacing the need for heavy passive damping systems
Solution Approach 2:
The wing extension uses the aircraft's existing rotational motion and aerodynamic forces to provide damping, effectively using the aircraft's own operational characteristics to stabilize itself without external heavy damping systems
2Stability of the object's composition
If structural stiffness is increased to improve stability margins, then stability is improved, but weight increases and fuel consumption increases
Solution Approach 1:
Instead of increasing static structural stiffness, the invention uses dynamic movement of the wing extension to provide stability, allowing the structure to remain lighter while maintaining stability margins through active damping during flight
3Device complexity
If the wing extension remains stationary in the slipstream, then structural simplicity is maintained, but download forces increase and efficiency decreases
Solution Approach 1:
The wing extension is designed to rotate dynamically with the rotor assembly, maintaining it within the slipstream throughout the rotation cycle, which continuously minimizes download forces and maximizes aerodynamic efficiency
Solution Approach 2:
The wing extension maintains continuous alignment with the slipstream throughout the rotor rotation cycle, ensuring uninterrupted minimization of download forces and sustained aerodynamic efficiency
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 solution effectively dampens structural modes without adding weight, improving stability and endurance by minimizing download forces and enhancing the aircraft's efficiency in forward flight.
Implementation Method 1
The wing extension is operable to oscillate at a dampening frequency to dampen a mode of the aircraft
Implementation Method 2
the minimal dimension of the wing extension remains in the slipstream of the proprotor
Data Source
AI summary
A tiltrotor aircraft includes a fuselage supporting first and second wings each having an outboard end. First and second nacelles are respectively coupled to the outboard ends of the first and second wings. The first and second nacelles each have an outboard end. First and second wing extensions are rotatably coupled, respectively, to the outboard ends of the first and second nacelles. First and second actuators are operable to respectively move the first and second wing extensions to dampen a mode of the first and second wings, thereby stabilizing the tiltrotor aircraft.