Pitch-Fold Lock Mechanism for Tiltrotor Rotor Blades
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Solution Overview
Problem
Tiltrotor aircraft face limitations in forward speed and range due to fundamental rotor system constraints, which restrict their versatility and operational capabilities compared to fixed-wing aircraft.
Innovation Solution
A blade lock or pitch-fold lock mechanism is introduced to enable and disable the folding and pitching degree of freedom of rotor blades, allowing for efficient transition between rotary and non-rotary flight modes, thereby optimizing rotor blade configuration for different flight conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If rotor blades are allowed to fold and pitch freely in tiltrotor aircraft, then vertical lift capability is maintained, but forward speed and range are limited due to aerodynamic drag and rotor system constraints
Solution Approach 1:
The rotor blade incorporates a folding mechanism with a fold lock and pitch lock that enable dynamic reconfiguration. The blade can transition between folded and unfolded states, and between different pitch angles, allowing the aircraft to adapt between vertical lift mode and forward flight mode efficiently
Solution Approach 2:
The blade lock mechanism is divided into separate functional components: a fold lock for controlling blade folding and a pitch lock for controlling blade pitching. This segmentation allows independent control of each degree of freedom, optimizing performance for different flight conditions
2Productivity
If rotor blades are locked in fixed position, then aerodynamic efficiency in forward flight improves, but transition between flight modes becomes difficult
Solution Approach 1:
The fold lock and pitch lock mechanisms are combined into an integrated blade lock assembly that controls both degrees of freedom. This merging simplifies the overall structure while maintaining the ability to independently control blade folding and pitching for efficient flight mode transitions
3Reliability
If passive overcenter locking is used in blade lock mechanism, then locking reliability improves, but mechanism complexity increases
Solution Approach 1:
The spring-loaded link provides passive overcenter locking that automatically engages and disengages based on the mechanism's position. The spring force creates a self-locking effect that maintains reliability without requiring additional actuators or complex control systems
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 blade lock mechanism enhances the operational flexibility of tiltrotor aircraft by allowing for efficient folding and pitching of rotor blades, which improves forward speed, range, and reduces aerodynamic drag, thereby addressing the limitations of existing rotor systems.
Implementation Method 1
A spring-loaded link pivotally connects both the fold lock and the pitch lock and is adapted to provide passive, overcenter locking in the fold-lock position
Implementation Method 2
An actuator is coupled to the pitch lock and is adapted to move the pitch lock and the fold lock between the fold-lock and pitch-lock positions
Data Source
AI summary
Embodiments are directed to a blade lock comprising a fold lock adapted to prevent folding of a rotor blade in a fold-lock position and to allow folding of the rotor blade in a pitch-lock position. The blade lock further comprises a pitch lock adapted to allow pitch movement of a rotor blade in a fold-lock position and to prevent pitch movement of the rotor blade in the pitch-lock position. A spring-loaded link pivotally connects both the fold lock and the pitch lock and is adapted to provide passive, overcenter locking in the fold-lock position. An actuator is coupled to the pitch lock and is adapted to move the pitch lock and the fold lock between the fold-lock and pitch-lock positions.