Independent Elevators Reduce Stabilizer Actuator Weight

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Solution Overview

Problem

The existing aircraft designs with adjustable horizontal stabilizers and elevators require oversized components to balance the strong axial forces generated by elevator deflection, leading to increased weight, volume, and energy needs due to the interdependence of these elements.

Innovation Solution

The aircraft features an adjustable horizontal stabilizer separate from the elevators, which are mounted independently on a second section of the structure, allowing for reduced dimensions and actuator size, as the elevators no longer impact the stabilizer, optimizing aerodynamic properties and reducing drag.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the elevator is fixed to the adjustable horizontal stabilizer by a hinge, then the aircraft can achieve pitch control through elevator deflection, but the dimensions and actuator size of the adjustable horizontal stabilizer must be oversized to balance the strong axial forces generated by elevator deflection

Engineering Contradiction:

Improvepitch control capabilityVSAvoidweight of adjustable horizontal stabilizer and actuator

Core Design Contradiction:

Ease of operationVSWeight of moving object

Solution Approach 1:

The patent divides the horizontal stabilizer system into two independent parts: the adjustable horizontal stabilizer and the elevator. The elevator is detached from the stabilizer and mounted separately on the fuselage structure, eliminating the mechanical connection that transmitted axial forces. This segmentation allows each component to be optimized independently, reducing the size and weight of the stabilizer and its actuator.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If the elevator is fixed to the adjustable horizontal stabilizer, then pitch control is achieved, but the volume of the equipment increases due to oversized components

Engineering Contradiction:

Improvepitch control capabilityVSAvoidvolume of adjustable horizontal stabilizer and actuator

Core Design Contradiction:

Ease of operationVSVolume of moving object

Solution Approach 1:

By segmenting the elevator from the adjustable horizontal stabilizer and mounting the elevator independently on the fuselage, the patent eliminates the need for oversized stabilizer components. The volume reduction is achieved because the stabilizer no longer needs to accommodate elevator hinges and withstand axial forces, allowing it to be compact and efficiently sized for its primary function.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If the elevator is fixed to the adjustable horizontal stabilizer, then pitch control is achieved, but the energy needs of the system increase due to oversized actuators

Engineering Contradiction:

Improvepitch control capabilityVSAvoidenergy consumption of actuators

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent separates the elevator control function from the stabilizer positioning function. The elevator actuator only needs to overcome small hinge moments at the fuselage mounting, while the stabilizer actuator only needs to position the stabilizer without elevator-induced axial forces. This segmentation dramatically reduces the power requirements of both actuators, lowering overall energy consumption.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extracts the elevator from the stabilizer assembly and relocates it to the fuselage structure. This extraction eliminates the transmission of axial forces from elevator deflection to the stabilizer actuator, allowing the stabilizer actuator to be smaller and consume less energy. The elevator actuator also benefits from having a reduced load due to the changed mounting configuration.

Inventive Principle:

Principle #2Taking out (Extraction)

4Reliability

If the adjustable horizontal stabilizer and actuator are oversized to balance axial forces, then pitch control stability is improved, but the device complexity increases

Engineering Contradiction:

Improvepitch control stabilityVSAvoidcomplexity of adjustable horizontal stabilizer system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the pitch control system into two independent control loops: stabilizer positioning and elevator deflection. This segmentation simplifies the mechanical design by eliminating the need for oversized stabilizer components to handle combined loads. Each actuator deals with a single, well-defined function, reducing mechanical complexity while maintaining control stability through independent optimization of each component.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS10633077B2Aircraft exhibiting independent elevators

Publication Date: 2020.04.28 AIRBUS OPERATIONS (SAS)

AI summary

An aircraft includes a structure exhibiting a median plane XZ and including a fuselage, a fixed vertical stabilizer at the rear of the fuselage, an adjustable horizontal stabilizer rotatably mounted about a horizontal axis on a first section of the structure, and extending on either side of the median plane XZ, and at the rear, two elevators mounted rotatably about a horizontal axis on a second section of the structure on either side of the median plane XZ independently of the adjustable horizontal stabilizer. In an aircraft of this kind, the elevators no longer have any impact on the adjustable horizontal stabilizer, which allows, among other things, the dimensions of the adjustable horizontal stabilizer, and also of the actuator operating them, to be reduced.