Rotating Thrust Director for Propulsive Anti-torque Nozzle
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Solution Overview
Problem
Conventional rotorcraft torque canceling devices, such as tail rotors, are unable to provide propulsive force and have limitations in efficiently managing torque and reducing noise and infrared signatures.
Innovation Solution
A propulsive anti-torque system that integrates a variable pitch fan driven by the main rotor's shaft, mixing engine exhaust with fan airflow to produce a mixed stream which is directed through a rotating thrust director and fixed nozzle assembly to generate thrust, anti-torque, and pro-torque vectors, reducing noise and infrared signatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional tail rotor is used for torque canceling, then torque control is achieved, but propulsive force cannot be provided and noise and infrared signatures are not reduced
Solution Approach 1:
The anti-torque system is designed to perform multiple functions: torque cancellation, forward thrust generation, and noise reduction. The thrust director nozzle can redirect exhaust flow to produce anti-torque moment while also providing propulsive force, eliminating the need for a separate tail rotor and reducing overall system noise signature.
Solution Approach 2:
The engine exhaust, which would otherwise be a harmful noise source and infrared signature, is redirected through the thrust director nozzle to perform useful work. The exhaust flow is used to generate both anti-torque moment and forward thrust, converting a harmful factor into a beneficial propulsive force.
2Power
If engine exhaust is directly expelled without mixing, then thrust is generated, but noise and infrared signatures increase
Solution Approach 1:
A mixing duct is introduced as an intermediary between the engine exhaust and the thrust director nozzle. Ambient air is mixed with the engine exhaust in the mixing duct, which reduces the temperature and velocity of the exhaust flow before it reaches the thrust director nozzle, thereby reducing noise and infrared signature while still maintaining thrust generation capability.
3Force
If a tail rotor is installed on the tail boom, then torque canceling is achieved, but the center of gravity shifts and structural reinforcement is required
Solution Approach 1:
The tail rotor is completely removed from the tail boom, extracting the harmful element that caused center of gravity shift and structural reinforcement requirements. The anti-torque function is instead achieved by redirecting the engine exhaust flow through the thrust director nozzle, which is positioned to generate the necessary anti-torque moment without adding weight to the tail boom or shifting the center of gravity.
4Device complexity
If the thrust director nozzle is fixed, then结构简单 (structure is simple), but thrust vector control is limited
Solution Approach 1:
The thrust director nozzle is made rotatable about the longitudinal axis of the aircraft, allowing dynamic adjustment of the thrust vector direction. This rotational capability enables the nozzle to redirect exhaust flow for different flight conditions, providing both anti-torque moment and forward thrust control while maintaining relatively simple mechanical implementation through a rotary actuator.
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 system enhances aircraft speed, reduces blade loading and vibration, improves ride quality, decreases noise and infrared signatures, and eliminates the need for a tail rotor, making rotorcraft safer and more efficient.
Implementation Method 1
a propulsive anti-torque system installed approximate to an engine in the rotorcraft and configured to selectively provide the rotorcraft with a forward thrust vector, an anti-torque vector, and a pro-torque vector
Implementation Method 2
The configuration and location of the fan allows the primary exhaust from the engine to be mixed with the air flow from the fan
Implementation Method 3
The mixed air flow from the fan and the engine passes through the tail boom and out the thruster nozzle
Data Source
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AI summary
The system of the present application includes a duct for receiving airflow from within a duct portion of a tailboom. The airflow is a mixture of fan driven air and engine exhaust. The system includes a fixed nozzle assembly with an anti-torque nozzle, a pro-torque nozzle, and a thrust nozzle. A rotating thrust director is located upstream of the fixed nozzle assembly. The rotating thrust director located is configured to selectively redirect airflow into one or more of the anti-torque nozzle, the pro-torque nozzle and the thrust nozzle.