Tiltrotor Blade Lock Assembly for Aeroelastic Stability
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Solution Overview
Problem
Tiltrotor aircraft face limitations in maximum airspeed due to forward airspeed induced proprotor aeroelastic instability during forward flight, restricting their high-speed cruising capabilities.
Innovation Solution
The implementation of a blade lock assembly with a drag brace, fold crank, and actuator assembly that allows for the rotation and locking of proprotor blades, enabling them to transition between horizontal and vertical planes of rotation, thereby minimizing drag and stabilizing the aircraft in both rotary and non-rotary flight modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If proprotors operate in forward flight mode with horizontal plane of rotation, then vertical thrust is provided for takeoff and hovering, but forward airspeed induced proprotor aeroelastic instability occurs limiting maximum airspeed
Solution Approach 1:
The proprotor blades are made rotatable relative to the proprotor hub, allowing dynamic adjustment of blade orientation between horizontal (for vertical thrust) and vertical (for forward flight) planes. This dynamic reconfiguration resolves the contradiction by enabling the system to adapt its configuration to different operational requirements, eliminating aeroelastic instability during high-speed forward flight while maintaining vertical thrust capability when needed
2Power
If proprotor blades are rotated to vertical plane for forward flight, then forward thrust is generated, but proprotor aeroelastic instability limits cruising speed
Solution Approach 1:
The blade rotation mechanism allows the proprotor to dynamically change its plane of rotation from horizontal to vertical based on operational needs. During high-speed forward flight, the blades can be rotated to a vertical plane where they function more like conventional airplane wings, reducing drag and eliminating aeroelastic instability, thereby enabling higher cruising speeds while maintaining forward thrust capability
3Adaptability or versatility
If proprotors are used instead of conventional propellers, then vertical takeoff and landing is enabled, but forward airspeed capability is reduced
Solution Approach 1:
The proprotor assembly is designed with rotatable blades that can operate in multiple configurations: horizontal plane for vertical thrust (helicopter mode) and vertical plane for forward thrust (airplane mode). This multi-functionality allows the same propulsion system to provide both vertical takeoff and landing capability and high-speed forward flight capability, resolving the contradiction between versatility and speed
Solution Approach 2:
The dynamic rotation capability of the proprotor blades enables the aircraft to transition between helicopter mode and airplane mode during flight. By rotating the blades to a vertical plane during forward flight, the system reduces drag and eliminates aeroelastic instability, thereby achieving high forward airspeed while maintaining the versatility to perform vertical takeoff and landing when needed
Data Source
AI summary
Disclosed is a blade lock assembly, which may include a drag brace coupled to a fold crank assembly and to a rotary wing blade and may further include an actuator assembly configured to be coupled to a rotary wing cuff. The actuator assembly may include an actuator pin housing, an actuation pin at least partially sheathed by the actuator pin housing, and an actuator configured to extend and retract the actuation pin away from and toward the actuator pin housing.