Hovering Aircraft Rotor Pitch Control Without Speed Change
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Solution Overview
Problem
Existing anti-torque rotors in helicopters and electrically propelled aircraft require complex mechanisms to adjust counter torque without varying rotational speed, leading to inefficiencies in noise reduction, energy consumption, and aerodynamic optimization.
Innovation Solution
A rotor system with adjustable blade angles using electric motors and a controlling element that allows quick adjustment of blade angles by varying the relative position of a hub and connection members, independent of rotational speed changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the rotational speed of the output shaft is reduced to reduce external noise, then noise is reduced, but the counter torque adjustment capability is limited and energy efficiency decreases
Solution Approach 1:
The patent applies the dynamics principle by making the blade angles adjustable during operation. The controlling element can vary the angle of attack of each blade independently while the rotor is rotating, allowing the counter torque to be adjusted without changing the rotational speed. This dynamic adjustment capability resolves the contradiction by enabling torque control at any given speed, rather than being constrained to fixed speed-torque relationships.
Solution Approach 2:
The patent changes the parameter of blade angle (angle of attack) to achieve counter torque adjustment. By varying the blade angles through the controlling element, the system can modify the aerodynamic characteristics and thus the counter torque generated, while maintaining constant rotational speed. This parameter change approach allows independent control of torque and speed, resolving the noted contradiction.
2Loss of energy
If the rotational speed of the output shaft is increased to improve energy efficiency, then energy efficiency is improved, but noise increases and aerodynamic optimization is limited
Solution Approach 1:
The dynamic adjustment of blade angles allows the system to operate at higher rotational speeds for improved energy efficiency while compensating for noise through aerodynamic optimization. The controlling element can adjust blade angles to optimize performance at any given speed, enabling the system to run efficiently at higher speeds without being constrained by noise or aerodynamic limitations.
Solution Approach 2:
By changing the blade angle parameters, the system can optimize aerodynamic characteristics at different operational requirements. When operating at higher speeds for energy efficiency, the blade angles can be adjusted to maintain optimal aerodynamic performance, thereby allowing the system to achieve energy efficiency improvements without being penalized by noise or aerodynamic suboptimization.
3Ease of manufacture
If fixed angles of attack are used to simplify manufacturing, then manufacturing simplicity is improved, but counter torque adjustment capability and aerodynamic optimization are reduced
Solution Approach 1:
The patent introduces a controlling element that enables dynamic adjustment of blade angles while maintaining a relatively simple overall structure. The hub with eccentric connection points provides a mechanical means for angle variation that adds functionality without requiring complex mechanisms. This dynamic capability allows counter torque adjustment while keeping the manufacturing complexity manageable.
Solution Approach 2:
The hub structure serves multiple functions: it supports the blades, provides the eccentric connection mechanism for angle adjustment, and integrates with the output shaft. This multi-functional design achieves counter torque adjustment capability without adding separate complex mechanisms, thereby maintaining manufacturing simplicity while gaining adaptability.
4Ease of operation
If the direction of rotation is inverted to change thrust direction in fixed angle rotors, then thrust direction is changed, but leading and trailing edges are exchanged and aerodynamic characteristics are compromised
Solution Approach 1:
The dynamic blade angle adjustment allows the system to change thrust direction by varying blade angles rather than inverting rotation direction. The controlling element can adjust each blade's angle of attack to redirect the thrust vector while maintaining the same rotational direction, thereby preserving the aerodynamic optimization of leading and trailing edges.
Solution Approach 2:
By changing the blade angle parameters, the system can alter the direction of thrust generation without changing the rotational direction. This parameter change approach allows thrust vector control while maintaining the aerodynamic characteristics of the blades, as the leading and trailing edges remain in their optimized positions relative to the rotation direction.
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 rapid adjustment of counter torque without changing rotational speed, optimizing aerodynamic characteristics, reducing noise, and improving energy efficiency.
Implementation Method 1
each of which is operated by a respective electric motor with a rotational speed selectively adjustable
Implementation Method 2
a plurality of blades (25) articulated on the hub (19) with fixed angles of attack... generating a thrust and, therefore, a counter torque
Implementation Method 3
constraining means (23) adapted to constrain the hub (19) and the controlling element (20) to one another and to vary the relative position between the hub (19) and the controlling element (20) when a rotational speed threshold of the output shaft (18) is reached
Data Source
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AI summary
A rotor (17, 17') is described, comprising a motor element (16) with an output shaft (18) rotatable around a first axis (C) and controllable with an acceleration (a); a hub (19, 19') connected to the output shaft (18); two blades (25) rotatable around a first axis (C); two connection members (21, 21') connected to the blades (25) and operable for adjusting the angles of attack (α, β, γ; α, β) of the blades (25); a controlling element (20, 20') connected to the connection members (21, 21') and rotatable around a first axis (C); and constraining means (23) adapted to constrain the hub (19, 19') and the controlling element (20, 20'); the constraining means (23, 23') keep the controlling element and the hub (20, 19; 20', 19') angularly integral with one another around the first axis (C) and in a first/second relative position with respect to one another, when the absolute value of the acceleration (a) is smaller/greater than a threshold value (Ta), so that the angles of attack (α, β, γ; α, β) assume first values; the constraining means (23, 23') allow the relative rotation between the controlling element and the hub (20, 19; 20', 19') between the first and second positions when the absolute value of the acceleration (a) reaches the threshold value (Ta).