Coaxial Counter-Rotating Propeller with Flexible Blade Pitch Control
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Solution Overview
Problem
Conventional aircraft control systems, particularly those with rigid propeller systems, face complexity and inefficiency in managing bending moments and thrust direction during maneuvers, while fully articulated rotor systems are overly complex and difficult to control effectively.
Innovation Solution
A co-axial, counter-rotating propeller system with a first rotor maintaining constant blade pitch and a second rotor with cyclically changing blade pitch, generating moments for aircraft control, is introduced, allowing for simplified control of aircraft attitude and thrust direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid turboprop propeller systems are used, then structural strength and simplicity are improved, but control flexibility and ability to manage bending moments during maneuvers deteriorate
Solution Approach 1:
The patent applies dynamics by making the propeller blades flexible rather than rigid. The blades are allowed to bend and deform under aerodynamic loads, enabling the system to adapt to varying flight conditions and maneuvers. This flexibility allows the propeller to manage bending moments effectively while maintaining structural integrity, resolving the contradiction between strength and control flexibility.
Solution Approach 2:
The patent changes the physical parameter of blade rigidity to flexibility. By using flexible blades that can dynamically adjust their shape and orientation during rotation, the system achieves both structural strength and control flexibility. The flexible blades can absorb and redistribute bending moments while maintaining the required structural integrity.
2Adaptability or versatility
If fully articulated rotor systems are used, then control flexibility and thrust vectoring capability are improved, but device complexity deteriorates
Solution Approach 1:
The patent extracts the essential control function from complex articulated rotor systems and applies it to a simpler flexible propeller configuration. Instead of using multiple articulated joints and complex mechanical linkages, the invention achieves thrust vectoring and attitude control through the flexible deformation of propeller blades during rotation. This eliminates the need for complex articulation mechanisms while maintaining control flexibility.
Solution Approach 2:
The patent replaces the mechanical articulation system with a flexible structural system. Instead of using mechanical joints, linkages, and actuators to achieve blade articulation, the invention uses the inherent flexibility of the propeller blades to achieve the same control objectives. This substitution dramatically reduces system complexity while maintaining control capabilities.
3Ease of manufacture
If conventional rigid propeller systems are used, then ease of manufacture is improved, but ability to generate control moments deteriorates
Solution Approach 1:
The patent introduces dynamic flexibility into the propeller blade design, allowing blades to bend and deform during rotation. This dynamic behavior enables the generation of control moments through differential blade deformation, while the overall manufacturing process remains relatively simple compared to fully articulated systems. The flexibility is achieved through smart material selection and structural design rather than complex mechanical assemblies.
Data Source
AI summary
An aircraft control system includes a propeller shaft assembly. Also included is first rotor operatively coupled to the propeller shaft assembly, the first rotor having a first plurality of blades mounted thereto, the first blades disposed at a substantially identical nominal pitch during rotation of the first rotor, the first rotor rotatable in a first direction. Further included is a second rotor operatively coupled to the propeller shaft assembly and rotatable in a second direction, the second rotor having a second plurality of blades mounted thereto, wherein a pitch of the second blades cyclically changes during rotation of the second rotor, the first rotor and the second rotor disposed and rotated proximate a fixed wing of an aircraft about a common axis extending parallel to a longitudinal axis of the aircraft, cyclically changing the pitch of the second plurality of blades generating a moment for controlling the aircraft.