Rotor Assembly Collective Pitch Control for VTOL
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current VTOL aircraft face challenges in achieving efficient thrust vectoring and control during vertical takeoff and landing, as well as forward flight, due to downwash inefficiencies and complex control requirements.
Innovation Solution
A rotor assembly with a mast that rotates at a constant speed, featuring a collective pitch control mechanism with spindle grips and a tilt control assembly, allowing for variable thrust output and vector control without changing rotational speed, integrated into an aircraft with an M-wing design and distributed propulsion system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If tiltrotor aircraft use fixed wing and proprotors for vertical takeoff and landing, then VTOL capability is achieved, but downwash inefficiencies occur due to interference from the fixed wing
Solution Approach 1:
The rotor hub assembly is made dynamically tiltable relative to the mast axis, allowing the rotor plane to change orientation between horizontal (for VTOL) and vertical (for forward flight). This dynamic reconfiguration eliminates fixed wing interference during vertical operations while maintaining forward flight capability.
Solution Approach 2:
The propulsion system is segmented into independent rotor hub assemblies that can be individually tilted and controlled. Each rotor hub with its spindle grips and rotor blades operates independently, allowing optimized positioning for either VTOL or forward flight without compromise.
2Loss of energy
If tiltwing aircraft rotate wing to vertical orientation for VTOL, then vertical thrust efficiency is improved, but control during hover becomes more difficult due to large surface area exposed to crosswinds
Solution Approach 1:
The aircraft uses multiple independent rotor hub assemblies rather than a single large tiltable wing. Each rotor hub operates independently with its own collective pitch control, distributing the control authority and reducing the impact of crosswinds on any single large surface.
Solution Approach 2:
The rotor blades employ variable pitch control through spindle grips that can independently adjust blade angle. This allows dynamic adjustment of lift characteristics to compensate for crosswind effects during hover while maintaining efficient vertical thrust generation.
3Adaptability or versatility
If helicopter rotors provide lift and thrust for hovering and vertical flight, then VTOL capability is achieved, but forward airspeed is typically lacking compared to fixed-wing aircraft
Solution Approach 1:
The rotor hub assembly tilts dynamically to change the thrust vector orientation. During forward flight, the rotor plane becomes vertical to provide forward thrust, while during VTOL it remains horizontal for vertical lift. This dynamic reconfiguration enables both high-speed forward flight and efficient vertical operations.
Solution Approach 2:
The same rotor assembly serves multiple functions: generating vertical lift during VTOL, providing forward thrust during horizontal flight, and enabling transition between modes. The tiltable rotor hub and variable pitch blades make the propulsion system universally capable of both helicopter-like VTOL and airplane-like forward flight.
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
Enables efficient transition between vertical takeoff and landing, hover, and forward flight modes with improved control and reduced interference, enhancing the aircraft's versatility and operational efficiency.
Implementation Method 1
The rotor blades are coupled to one of the spindle grips and are rotatable therewith about the respective pitch change axis... each operable to generate a variable thrust output
Data Source
AI summary
A rotor assembly for an aircraft operable to generate a variable thrust output at a constant rotational speed. The rotor assembly includes a mast rotatable at the constant speed about a mast axis. A rotor hub is coupled to and rotatable with the mast. The rotor hub includes a plurality of spindle grips extending generally radially outwardly. Each of the spindle grips is coupled to one of a plurality of rotor blades and is operable to rotate therewith about a pitch change axis. A collective pitch control mechanism is coupled to and rotatable with the rotor hub. The collective pitch control mechanism is operably associated with each spindle grip such that actuation of the collective pitch control mechanism rotates each spindle grip about the respective pitch change axis to collectively control the pitch of the rotor blades, thereby generating the variable thrust output.