Pneumatic Yaw Control Effector for Stealth Aircraft

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Solution Overview

Problem

Conventional aircraft control surfaces, such as rudders and ailerons, become ineffective at high angles of attack, and are undesirable on stealth aircraft, which face challenges in maintaining directional control without vertical tails.

Innovation Solution

The use of pneumatic control effectors, including blowing slots at the leading edge of wings, which create yaw control by modifying pressure distribution, allowing for cross-blowing methods to generate significant yaw moments at both low and high angles of attack, potentially replacing traditional control surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional control surfaces (rudders and ailerons) are used, then directional control is achieved at low angles of attack, but control effectiveness is lost at high angles of attack

Engineering Contradiction:

Improvecontrol effectivenessVSAvoidangle of attack range

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces conventional mechanical control surfaces (rudders and ailerons) with pneumatic control effectors that use pressurized fluid jets. These jets modify the pressure distribution on the aircraft surface to generate control moments, eliminating the need for traditional hinged surfaces that become ineffective at high angles of attack.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention employs pneumatic actuators that deliver pressurized fluid through slots or holes in the aircraft structure. By controlling the direction and magnitude of these fluid jets, the system generates aerodynamic forces and moments for roll, pitch, and yaw control across a wide range of angles of attack, including high AoA conditions where conventional surfaces fail.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Reliability

If vertical tails and rudders are added for directional control, then yaw control is improved, but stealth characteristics are degraded

Engineering Contradiction:

Improveyaw control capabilityVSAvoidstealth performance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the yaw control function from the vertical tail/rudder configuration and relocates it to pneumatic effectors positioned on the fuselage or wing surfaces. This eliminates the need for protruding vertical surfaces that create radar cross-section issues, while maintaining yaw control capability through fluid-based actuation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The pneumatic control effectors serve multiple functions: they provide roll, pitch, and yaw control authority, and can operate across the entire angle of attack range. This multi-functionality replaces the specialized vertical tail structure, achieving both stealth characteristics and comprehensive control capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If pneumatic control effectors are used, then control effectiveness at high angles of attack is improved, but device complexity increases

Engineering Contradiction:

Improvehigh AoA control performanceVSAvoidpneumatic system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the control effector functionality directly into the aircraft structure by integrating pneumatic slots or holes into the fuselage and wing surfaces. The control system shares common pneumatic infrastructure for all control axes, reducing overall system complexity despite the advanced control capabilities enabled at high angles of attack.

Inventive Principle:

Principle #5Merging (Combining)

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 solution maintains horizontal directional control without rudders and ailerons, particularly at angles from 0 to 50 degrees, and enhances the lift-to-drag ratio by up to 50%, improving the range and endurance of flight vehicles.

Implementation Method 1

The control effect of this invention occurs by lowering the pressure on the surface of the aircraft in the vicinity of or near the jet slots

Methodology Applied

Scientific EffectPressure distribution modification: Pressure Gradient

Implementation Method 2

The pneumatic control effector of this invention uses jets of air communicating or passing through four slots located at or near the nose and midspan region on the leading edge of the wings

Methodology Applied

Scientific EffectJet flow: Jet

Data Source

PatentUS9944383B2Pneumatic yaw control effector for aircraft

Publication Date: 2018.04.17 ILLINOIS INSTITUTE OF TECHNOLOGY

AI summary

An apparatus and method for controlling a yaw moment of a flight vehicle, such as an aircraft. A wing structure of the flight vehicle has a first opening or actuator positioned by a first apex section of a first side of the wing, and has a second opening or actuator positioned away from or at a distance from a second apex section of a second side of the wing. The first side and the second side can each be positioned or located opposite a centerline of the wing or wing structure. A pressure source or other pressure supply device is in communication with the first opening or actuator and the second opening or actuator to which a pressurized fluid, such as air, is controlled and delivered to control or vary the yaw moment of the flight vehicle.