Tiltrotor Wing Extensions Synchronized with Rotor Slipstream
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Solution Overview
Problem
Tiltrotor aircraft with fixed nacelles experience high download forces on wing extensions due to rotorwash during vertical takeoff, hovering, and landing, reducing lift generation by proprotors.
Innovation Solution
A pylon assembly with rotatably coupled wing extensions that synchronize with the rotor assembly, keeping the minimal dimension within the slipstream, and a stabilization system using actuators and feedback loops to oscillate wing extensions and dampen structural modes, reducing download forces and enhancing stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wing extensions are attached to fixed nacelles, then the effective wingspan is increased to assist cruise efficiency and range, but high download forces are caused on the wing extensions due to rotorwash during vertical takeoff, hovering, and landing
Solution Approach 1:
The wing extensions are made dynamically rotatable relative to the fixed nacelles, allowing them to change orientation between horizontal (for cruise efficiency) and vertical/aligned with rotor wash (to minimize download forces during VTOL operations). This dynamic adjustment resolves the contradiction by adapting the wing extension configuration to different flight phases.
Solution Approach 2:
The orientation parameter of the wing extensions is changed based on flight mode. During cruise, the wing extensions are positioned horizontally to maximize wingspan and efficiency. During vertical takeoff, hovering, and landing, the wing extensions are rotated to align with the rotor wash direction, changing their aerodynamic parameters to minimize harmful download forces.
2Device complexity
If wing extensions remain fixed in horizontal orientation, then structural simplicity is maintained, but lift generation by proprotors is reduced due to rotorwash interference
Solution Approach 1:
The wing extensions incorporate a rotation mechanism that allows them to dynamically adjust their orientation relative to the nacelles and rotor assembly. This dynamic capability enables the system to optimize lift generation by positioning wing extensions away from rotor wash during vertical operations while maintaining structural efficiency during cruise.
Solution Approach 2:
The wing extension system is segmented into rotatable sections that can independently adjust their orientation. This segmentation allows different parts of the wing structure to be positioned optimally for different flight phases, reducing rotor wash interference during VTOL while maintaining cruise efficiency.
3Force
If wing extensions are made rotatable to synchronize with rotor assembly, then download forces are minimized by keeping minimal dimension in slipstream, but device complexity increases
Solution Approach 1:
The rotation mechanism for the wing extensions is merged with the existing rotor assembly mounting structure. The wing extensions are coupled to the rotor assembly through shared mechanical interfaces and actuation systems, so that the same rotational actuation that positions the rotor also positions the wing extensions, reducing overall system complexity.
Solution Approach 2:
The rotational mechanism serves multiple functions: it positions both the rotor assembly and the wing extensions simultaneously, and it can operate in different modes (full rotation, partial rotation, locked positions) depending on flight phase. This multi-functionality reduces the need for separate dedicated mechanisms for each component.
4Stability of the object's composition
If actuators and feedback loops are added for stabilization, then structural vibrations are dampened and stability is improved, but device complexity and energy consumption increase
Solution Approach 1:
Feedback sensors detect structural vibrations and wing extension position, and this information is fed to control systems that adjust actuator commands in real-time. This closed-loop feedback stabilizes the aircraft by continuously counteracting disturbances while optimizing wing extension orientation during flight transitions.
Solution Approach 2:
The stabilization system utilizes controlled mechanical vibrations and oscillations of the wing extensions to counteract unwanted structural vibrations through active damping. By introducing controlled vibrational movements, the system reduces overall structural vibrations and improves stability during flight operations.
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
Minimizes download forces on wing extensions by keeping them within the slipstream and stabilizes the aircraft by actively oscillating wing extensions to counteract structural vibrations, improving lift generation and overall flight efficiency.
Implementation Method 1
A rotor assembly is rotatably coupled to the fixed pylon and is operable to rotate between a vertical takeoff and landing orientation and a forward flight orientation. The rotor assembly includes a proprotor operable to produce a slipstream.
Implementation Method 2
The wing extension is operable to rotate generally with the rotor assembly such that the minimal dimension of the wing extension remains in the slipstream of the proprotor.
Implementation Method 3
An actuator is coupled to the wing extension and is operable to move the wing extension to dampen a mode of the wing, thereby stabilizing the tiltrotor aircraft.
Data Source
AI summary
A pylon assembly for a tiltrotor aircraft includes a fixed pylon having an outboard end. A rotor assembly is rotatably coupled to the fixed pylon and is operable to rotate between a a vertical takeoff and landing orientation and a forward flight orientation. The rotor assembly includes a proprotor operable to produce a slipstream. A wing extension is rotatably coupled to the outboard end of the fixed pylon. The wing extension is operable to rotate generally with the rotor assembly such that a minimal dimension of the wing extension remains in the slipstream of the proprotor.