Rotary Actuator Control Surface Mounting for Aircraft Weight Reduction

Solution Overview

Problem

Conventional aircraft control surface arrangements face challenges in reducing volume and weight while maintaining torque requirements as aircraft fly faster and higher, leading to increased complexity and cost with existing solutions.

Innovation Solution

A rotary actuator is used to both mount and pivot control surfaces, eliminating the need for separate hinges and linear actuators, and delivering torque from a central location to reduce part count and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional linear actuators with bell crank arms are used to control rotation of the control surface, then the control surface can be moved, but the arrangement consumes excessive volume and weight as aircraft fly higher and faster

Engineering Contradiction:

Improvevolume of control surface arrangementVSAvoidtorque required to move control surface

Core Design Contradiction:

Volume of moving objectVSPower

Solution Approach 1:

The patent combines the hinge and actuator into a single integrated rotary actuator assembly. The hinge is positioned at the longitudinal center of the control surface, and the rotary actuator is mounted at the hinge location, merging two separate components (hinge and linear actuator with bell crank arm) into one compact unit that delivers torque directly at the pivot point.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The rotary actuator serves multiple functions: it acts as both the actuator that moves the control surface and as the hinge that pivotally supports the control surface on the airframe. This multi-functional design eliminates the need for separate hinges and linear actuators, reducing overall volume and weight while maintaining the required torque capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Length of stationary object

If the length of the bell crank arm is reduced to accommodate thinner airframes, then the airframe thickness is reduced, but the torque required to move the control surface increases

Engineering Contradiction:

Improvethickness of airframeVSAvoidtorque required to move control surface

Core Design Contradiction:

Length of stationary objectVSPower

Solution Approach 1:

The patent replaces the conventional linear actuator and bell crank arm mechanical system with a rotary actuator that delivers torque directly at the hinge location. This substitution eliminates the need for long bell crank arms and allows the airframe to be thinner while maintaining the required torque capability through direct central mounting.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Power

If additional linear actuators are employed to control the control surface, then the torque requirement is met, but the cost, weight, part count, and complexity increase

Engineering Contradiction:

Improvetorque capabilityVSAvoidcomplexity of control arrangement

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The rotary actuator serves multiple functions: it acts as both the actuator that moves the control surface and as the hinge that pivotally supports the control surface on the airframe. This multi-functional design eliminates the need for separate hinges and linear actuators, reducing overall volume and weight while maintaining the required torque capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the hinge and actuator into a single integrated rotary actuator assembly. The hinge is positioned at the longitudinal center of the control surface, and the rotary actuator is mounted at the hinge location, merging two separate components (hinge and linear actuator with bell crank arm) into one compact unit that delivers torque directly at the pivot point.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11077934B2Aircraft, control surface arrangements, and methods of assembling an aircraft

Publication Date: 2021.08.03 GULFSTREAM AEROSPACE CORP

AI summary

An aircraft, a control surface arrangement, and a method of assembling an aircraft are disclosed herein. In an exemplary embodiment, the aircraft includes, but is not limited to, an airframe, a control surface, and a rotary actuator. The rotary actuator rotatably mounts the control surface to the airframe. The rotary actuator supports the control surface on the airframe and is configured to rotate the control surface with respect to the airframe when the rotary actuator is actuated. The rotary actuator is further configured to deliver torque to the control surface from a longitudinally intermediate portion of the rotary actuator.