Electric Tail Rotor Control for Aircraft
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Solution Overview
Problem
Conventional rotary-wing aircraft tail rotors are not optimized independently of the main rotor, leading to suboptimal performance during most flight phases due to fixed mechanical transmission constraints, and the use of electric motors to control tail rotors can result in 'setpoint overrun' and inertia issues.
Innovation Solution
A rotary-wing aircraft with a tail rotor driven by an electric motor and a regulation system that controls both the motor's speed and the pitch of the blades, allowing for independent optimization of the main and tail rotors, and enabling rapid adaptation to flight conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed mechanical transmission is used to link the main rotor and tail rotor, then the aircraft structure is simple and reliable, but the tail rotor performance is not optimized during most flight phases
Solution Approach 1:
The patent replaces the conventional mechanical transmission system with an electric motor to drive the tail rotor. This substitution allows the tail rotor to be controlled independently from the main rotor, enabling optimization of tail rotor performance across different flight phases without being constrained by the fixed mechanical linkage. The electric motor provides precise control capability while maintaining system reliability.
2Productivity
If an electric motor is used to control the tail rotor independently, then the tail rotor performance is optimized and independent sizing is possible, but setpoint overrun and inertia issues occur
Solution Approach 1:
The patent implements a dynamic control system with variable pitch blades for the tail rotor. The pitch angle of the blades can be adjusted in real-time to optimize performance across different flight conditions. This dynamic adjustment capability allows the system to adapt to varying requirements, reducing setpoint overrun by modulating the aerodynamic characteristics of the tail rotor blades according to actual flight demands.
Solution Approach 2:
The patent changes the operational parameters of the tail rotor by implementing variable pitch control. By adjusting the blade pitch angle as a controllable parameter, the system can optimize the tail rotor's thrust characteristics for different flight phases. This parameter change approach enables precise control while mitigating the inertia effects of the electric motor-driven system.
3Reliability
If the tail rotor is dimensioned for a penalizing flight phase, then the aircraft can handle extreme conditions, but the tail rotor is over-sized for frequent flight phases
Solution Approach 1:
The variable pitch mechanism allows the tail rotor to dynamically adjust its thrust output. During extreme conditions, the pitch can be increased to provide maximum anti-torque capability. During normal flight phases, the pitch is reduced to optimize energy efficiency. This dynamic adaptation eliminates the need to oversize the tail rotor for rare penalizing conditions, as the system can scale its performance to match actual requirements.
Solution Approach 2:
By changing the blade pitch parameter, the system can vary the tail rotor's thrust generation capability. This allows the same physical tail rotor to operate efficiently across a wide range of flight conditions, from maximum anti-torque requirements in extreme conditions to minimal thrust during normal operations. The parameter change approach enables energy-efficient operation during frequent flight phases while maintaining capability for extreme conditions.
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
This configuration allows for optimized performance of both rotors, reduces 'setpoint overrun', and provides flexible control to counter wind gusts and aerodynamic disturbances, improving energy efficiency and pilot control experience.
Implementation Method 1
a motor installation (4) driving a main power transmission box (3) rotating a main rotor (2)... an electric motor (9) arranged to set the tail rotor (5) in rotation
Implementation Method 2
a device (20) for modifying this pitch... allowing for independent optimization of the main and tail rotors
Data Source
AI summary
The aircraft (1) has a control unit (30) for controlling a pitch modification device (20), and an electric motor (9) for rotating a rear rotor (5). A regulation unit (TRCU) is connected to the electric motor and the pitch modification device by the control unit. The regulation unit provides a pitch instruction transmitted to the pitch modification device, and an engine parameter control instruction transmitted to the electric motor. An electric generator (7) is electrically connected to a power transmission gear box (3) for supplying power to the electric motor. An independent claim is also included for a method for optimizing an operation of a rear rotor of an aircraft.