Contra-bevel Control Surface Actuation for Drag Reduction

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Solution Overview

Problem

Conventional aircraft control surface actuation systems experience inefficiencies due to discontinuities and space requirements, leading to increased drag and reduced performance, particularly in advanced airframes where traditional actuation schemes disrupt airflow and require significant packaging.

Innovation Solution

A contra-bevel driven flight control system that mechanically couples an airfoil and control surface using forward, mid, and aft beveled rotors, allowing counter-rotation and angular deflection to achieve maximum mechanical advantage and smooth deflection of control surfaces, potentially reducing discontinuities and drag.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional actuation schemes with large linear actuators and bell cranks are used, then control surfaces can be actuated, but outside mold line bumps and discontinuities form that adversely impact airflow and increase drag

Engineering Contradiction:

Improveactuation capabilityVSAvoiddrag

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The actuation mechanism is nested within the control surface structure itself. The beveled rotors and actuator are integrated into the control surface's internal volume, allowing the actuation system to be contained within the existing airfoil contour without requiring external bumps or discontinuities.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention transitions from traditional linear actuation in the longitudinal dimension to rotational actuation about a spanwise axis. The beveled rotors convert rotational motion into the desired control surface deflection, utilizing a different dimensional approach that eliminates the need for external linear actuators.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If traditional actuation schemes are used, then control surfaces can be actuated, but large packaging space and cutouts are required for hinge actuation

Engineering Contradiction:

Improveactuation capabilityVSAvoidpackaging space

Core Design Contradiction:

Ease of manufactureVSVolume of stationary object

Solution Approach 1:

The actuation mechanism is merged with the control surface structure. The beveled rotors are integrated into the control surface's internal volume, combining the actuation function with the control surface itself and eliminating the need for separate packaging spaces and cutouts.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The actuation system components are nested within the control surface's internal volume. The beveled rotors and actuator are contained within the existing structural envelope, maximizing space utilization and eliminating external packaging requirements.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Strength

If control surfaces are made as rigid structures, then structural strength is maintained, but discontinuities form at the hinge area that increase drag

Engineering Contradiction:

Improvestructural strengthVSAvoiddrag

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The invention uses curved, beveled rotor surfaces instead of flat, rigid connections. The beveled geometry creates smooth transitional surfaces that maintain structural integrity while eliminating abrupt discontinuities at the hinge area, thereby reducing drag.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The control surface is designed with dynamic characteristics that allow for smooth rotation about the spanwise axis. The beveled rotors enable continuous, smooth motion without the abrupt transitions associated with traditional rigid hinge connections, maintaining strength while reducing drag.

Inventive Principle:

Principle #15Dynamics

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 mechanical advantage and reduces drag by enabling smooth control surface deflection, improving aerodynamic efficiency and reducing the need for large packaging, while allowing for more complex and efficient control surface positioning.

Implementation Method 1

The angular rotation between the forward beveled rotor and the aft beveled rotor deflects the aft beveled rotor and the aft chordwise axis within the control surface. Additionally, this method allows the control surface to be deflected with maximum mechanical advantage when the control surface is fully deflected.

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentUS7731123B2Contra-bevel driven control surface

Publication Date: 2010.06.08 LOCKHEED MARTIN CORP

AI summary

A contra-bevel driven control mechanism repositions a control surface in a fluid environment such as an aerodynamic or hydrodynamic environment. This involves mechanically coupling an airfoil and a control surface. The control surface may pivot about a spanwise axis between upwardly deflected and downwardly deflected positions. A forward beveled rotor mounted to the airfoil and an aft beveled rotor mounted to the control surface counter rotate. The forward beveled rotor rotates about a forward chordwise axis within the airfoil while the aft beveled rotor rotates about an aft chordwise axis within the control surface. The angular rotation between the forward beveled rotor and the aft beveled rotor deflects the aft beveled rotor and the aft chordwise axis within the control surface. Additionally, this method allows the control surface to be deflected with maximum mechanical advantage when the control surface is fully deflected.