Variable-Sweep Wing Tiltrotor for High-Speed Flight
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Tiltrotor aircraft are limited by forward airspeed induced proprotor aeroelastic instability, which restricts their maximum airspeed in forward flight.
Innovation Solution
A variable-sweep wing system for tiltrotor aircraft that shifts between a substantially straight wing configuration for low-speed forward flight and a swept wing configuration for high-speed forward flight, using a driveshaft and crank linkage to transmit torque and facilitate wing configuration changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If tiltrotor aircraft use a fixed straight wing configuration for forward flight, then the proprotors can maintain stable operation, but the maximum airspeed is limited due to aeroelastic instability
Solution Approach 1:
The patent applies the dynamics principle by making the wing sweep angle variable rather than fixed. The wing airframe is configured to shift between a substantially straight wing configuration and a swept wing configuration based on flight conditions. This dynamic adjustment allows the aircraft to overcome the speed limitation imposed by proprotor aeroelastic instability by sweeping the wings at higher speeds, thereby resolving the contradiction between achieving higher speeds and maintaining proprotor stability
Solution Approach 2:
The patent changes the geometric parameter of the wing sweep angle to resolve the contradiction. By varying the sweep angle from straight to swept configuration, the aircraft can operate at higher airspeeds without experiencing proprotor aeroelastic instability. This parameter change allows the system to adapt to different flight regimes and overcome the speed limitation while maintaining operational reliability
2Speed
If tiltrotor aircraft use a variable-sweep wing configuration to increase speed, then maximum airspeed is improved, but the device complexity increases due to additional linkage mechanisms
Solution Approach 1:
The patent applies the universality principle by designing the wing linkage mechanism to perform multiple functions simultaneously. The same linkage system that enables wing sweeping also facilitates the shifting between straight and swept configurations, and can be integrated with the existing proprotor tilt mechanism. This multi-functionality reduces the need for separate dedicated mechanisms, thereby limiting the increase in device complexity while still achieving the speed improvement benefit
3Loss of energy
If tiltrotor aircraft maintain pylon axes parallel to fuselage axis in both configurations, then drag penalties are minimized, but the structural design complexity increases
Solution Approach 1:
The patent applies the dynamics principle by making the pylon axis orientation adaptable rather than fixed. The pylon is designed to maintain its axis parallel to the fuselage axis in both straight and swept wing configurations through a movable or adjustable mounting mechanism. This dynamic alignment capability minimizes drag penalties across different flight regimes while the mechanism itself is integrated into the existing wing-pylon-fuselage structure, limiting the increase in structural design complexity
Data Source
AI summary
A variable-sweep wing for a tiltrotor aircraft includes a fuselage link coupled to the fuselage and a pylon link coupled to a pylon. A wing airframe has a root end pivotably coupled to the fuselage link and a tip end pivotably coupled to the pylon link. A driveshaft is coupled between the fuselage link and the pylon link and is positioned within the wing airframe. The driveshaft is operable to transmit torque from the main gearbox to a proprotor gearbox. A crank is coupled between the fuselage link and the pylon link and is positioned within the wing airframe. The fuselage link, the pylon link, the driveshaft and the crank form a linkage such that pivoting the crank relative to the fuselage link causes the wing airframe to shift between a substantially straight wing configuration for low-speed forward flight and a swept wing configuration for high-speed forward flight.