Differential Thrust Control for Blown Lift Aircraft Yaw Stability
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Solution Overview
Problem
Conventional aircraft control systems face challenges in managing undesirable yaw conditions, especially at low airspeeds, where aerodynamic control surfaces have limited authority, and frequent rudder cycling occurs, leading to inefficient compensation for yaw oscillations and potential engine failures.
Innovation Solution
A differential thrust control system for blown lift aircraft, which includes a computing device that selectively operates thrust-producing devices, the rudder, and roll control devices based on sensor inputs and mode settings, allowing for automatic application of differential thrust to stabilize the aircraft and reduce the need for a large rudder or vertical tail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aerodynamic control surfaces (rudder) are used to compensate for yaw conditions, then yaw control is achieved, but at low airspeeds the control authority is limited and frequent rudder cycling occurs
Solution Approach 1:
The patent combines aerodynamic control surfaces with thrust-producing devices to create a unified control system. The thrust devices are integrated with the wing structure and work cooperatively with the rudder and roll control devices to provide enhanced yaw control authority at low airspeeds, eliminating the limitation of using aerodynamic surfaces alone.
Solution Approach 2:
The control system introduces a computing device as an intermediary that receives sensor inputs and automatically coordinates the operation of thrust-producing devices, rudder, and roll control devices. This intermediary processing enables sophisticated control strategies that compensate for yaw conditions more effectively than direct pilot control or simple aerodynamic surfaces alone.
2Stability of the object's composition
If a large rudder and vertical tail are used to compensate for engine failure and adverse yaw, then yaw stability is improved, but device complexity and aircraft size increase
Solution Approach 1:
The patent replaces the reliance on large mechanical aerodynamic surfaces (rudder and vertical tail) with a control system that uses thrust-producing devices integrated into the wing structure. This substitution allows yaw stability to be achieved through differential thrust control rather than through oversized aerodynamic surfaces, reducing overall device complexity.
Solution Approach 2:
The control system segments the yaw control function across multiple independent components: individual thrust-producing devices on each wing, the rudder, and roll control devices. This segmentation allows each component to operate independently and be optimized for its specific function, rather than requiring one large monolithic rudder system.
3Stability of the object's composition
If frequent rudder cycling is used to compensate for yaw oscillations, then yaw damping is achieved, but control system wear and energy consumption increase
Solution Approach 1:
The control system dynamically adjusts the operation of thrust-producing devices and control surfaces based on real-time sensor inputs and computing device processing. This dynamic coordination allows the system to dampen yaw oscillations more efficiently by distributing the control action across multiple components rather than relying on frequent, high-energy rudder cycling alone.
Data Source
AI summary
An aircraft may include a tail having a rudder and a pair of wings. The pair of wings may include at least one flap and at least one roll control device. The aircraft may also include at least two thrust-producing devices. The aircraft may also include a differential thrust control system including a computing device having at least one processor. The at least one processer may be configured to control an attitude of the aircraft by selectively operating the at least two thrust-producing devices, the rudder, and the at least one roll control device based at least in part on a plurality of conditions provided by a plurality of sensors on the aircraft and a selected mode setting of a mode control panel. The computing device may be communicatively coupled to the at least two thrust-producing devices, the rudder, and the at least one roll control device.