The Design and Development of an Active Smart Wing Model ATAK Technologies

Team Structure Thomas Ayers Thomas Ayers Project Leader Project Leader Robert Aguirre Robert Aguirre Senior Testing Research Specialist Senior Testing Research Specialist Kevin Mackenzie Kevin Mackenzie Senior Modeling and Design Specialist Senior Modeling and Design Specialist Vu Tran Vu Tran Senior Research Specialist Senior Research Specialist Dr. R. O. Stearman Dr. R. O. Stearman University of Texas Faculty Consultant University of Texas Faculty Consultant

Presentation Overview Project Objectives Project Objectives Aerodynamic Theory Aerodynamic Theory Model Design Model Design Model Testing Options Model Testing Options Project Accomplishments Project Accomplishments Recommended Future Pursuits Recommended Future Pursuits Summary Summary Questions Questions

Project Background Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions Randall Bolding Wrote a master’s thesis in 1978 in which a wing model was used to research the use of a stabilator as an active control to suppress flutter Lockheed Martin Corporation A research project on the benefits that an active wing can provide in contemporary aircraft design

High Airspeed Benefits Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions At high airspeeds normally latent aerodynamic forces become powerful enough to affect the flow about the airfoil These changes cause torsional moments on the wing Theoretically, the use of active wing control on the leading edge flaps and ailerons can be used in order to better control these latent aerodynamic forces

Low Airspeed Benefits Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions At low speeds airflow about the wing can separate from the wing causing a “stall” In natural flight, resonant flapping is used to sustain flight at low flight speeds Theoretically, oscillating the wings by using the control surfaces would create high lift conditions for short, low airspeed maneuvers

Project Objective Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions To create an active wing model for the purpose of defining relationships between control surface oscillation and flight performance

Aerodynamic Theory Project Objectives Project Objectives Aerodynamic Theory Aerodynamic Theory Model Design Model Design Model Testing Options Model Testing Options Project Accomplishments Project Accomplishments Recommended Future Pursuits Recommended Future Pursuits Summary Summary Questions Questions

Desirable Flow Types Background Background Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions Attached-flow: Difference of the circulations of the upper and lower boundary layers create a lift force near a quarter chord of the airfoil. (figure a) Detached-vortex-flow: rolled-up leading edge vortices create additional lift. (figure b) [4]

Problems Encountered Background Background Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions When a critical angle of attack achieved to create high lift, separated unsteady flow is unavoidable, and the vortices formed become uncontrollable once they leave the body.  Unsteady separation  Vortex shedding  Vortex breakdown

Separation Control Background Background Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions To control separation, essentially the boundary vorticity flux control, a relationship between pressure, inertial, and viscous forces must be utilized. Methods for controlling separation: 1) Control tangential pressure gradient: proper design of airfoil and wing geometry 2) Control skin friction field: modify local skin friction field near critical points 3) Introduce local movable wall: oscillating flaps

Reattachment Control Background Background Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions When the boundary layer is already separated, control of its reattachment is also feasible by utilizing unsteady excitations. Example: Small leading-edge oscillating flap was used to forced the shear layer separated from a sharp leading edge to attach to just the upstream of a round trailing edge, hence captured a strong vortex above a two-dimensional airfoil with angle of attack up to 27 degree. Lift was increased by 60%. [4]

Reattachment Control Background Background Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions The inviscid vortex method can be used to compare flow patterns with or without leading-edge oscillation Case (a) : leading-edge vortex moves downstream as new vorticies start to form. The leading edge vortex cuts off the trailing edge vortex sheet. The main vortex will eventually shed. Case (b): main vortex is stabilized and stays close to the wing with nearly uniform vorticity distribution [4]

Reattachment Control Background Background Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions An additional example: Poly Vinylidence Flouride (PVDF) piezoelectric film was used on the surface of a NACA 0012 airfoil to generate surface oscillation through polarization changes in the material [5] Non-oscillated case: Max lift coefficient = 0.72, stall angle = 14 degree Oscillated case: Max lift coefficient = 0.76, stall angle = 15 degree [5] [5]

Reattachment Control Background Background Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions For a highly swept wing, unsteady surface excitations focus on delaying vortex breakdown, or can be used to maintain highly concentrated and stable leading-edge vortices Schematic of mini-upper wing [4]

Reattachment Control Background Background Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions Mini-upper Wing: The wing has a larger incidence than the main wing, thus forcing the flow below it to converge. This implies an additional axial acceleration at the vortex core, and therefore delays its burst. However, the applicable angle of attack is limited, due to limitations created by the wing design

Model Design Project Objectives Project Objectives Aerodynamic Theory Aerodynamic Theory Model Design Model Design Model Testing Options Model Testing Options Accumulated Project Work Accumulated Project Work Recommended Future Pursuits Recommended Future Pursuits Summary Summary Questions Questions

Actuator Designs Background Background Theory Theory Model Model Work Work Summary Summary Questions Questions Hydraulic Actuator Electromechanical Actuator Electric Motor

Benefits of ATAK’s Design Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions Size of Control System – Electric motor and shaft will be half the size of the previous groups Ease of Operation – Does not require understanding of complex controller Able to Test – By taking wind tunnel dimensions into account when designing we make sure that we will be able to mount the wing in order to obtain Cl and Cd measurements Flexibility – Leading and trailing edge flaps will be able to oscillate. Will be able to control angle of deflection and phase between flaps

Model Design Overall Model Assembly Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions

Model Design Wing Spar, Engine and Rods Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions

Model Design Gearing Assembly Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions

Model Design Bevel Gears Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions

Model Design Actuation System – Push/Pull Rods Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions

Model Design Actuation System including Control Surfaces Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions

Model Design Wing Model Without Modified Control Surfaces Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions

Model Design Wing Model With Deflected Control Surfaces Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions

Model Design Overall Model Assembly Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions

Model Testing Options Project Objectives Project Objectives Aerodynamic Theory Aerodynamic Theory Model Design Model Design Model Testing Options Model Testing Options Accumulated Project Work Accumulated Project Work Recommended Future Pursuits Recommended Future Pursuits Summary Summary Questions Questions

Background Background Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions Model Testing Goals Take next step in project development Take next step in project development Obtain and reduce data Obtain and reduce data Conduct repeated tests to ensure quality data acquired Conduct repeated tests to ensure quality data acquired

Testing Data Acquisition Background Background Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions Relationship between oscillation frequency and Relationship between oscillation frequency and Variations of coefficient of lift Variations of coefficient of lift Pressure distributions over wing Pressure distributions over wing Wing spar strain Wing spar strain Wing tip flutter Wing tip flutter Relationships can be used to find optimum frequencies for Relationships can be used to find optimum frequencies for Maximizing coefficient of lift Maximizing coefficient of lift Minimizing wing spar strain Minimizing wing spar strain Minimizing wing tip flutter Minimizing wing tip flutter

Model Testing Equipment Background Background Theory Theory Model Model Testing Testing Work Work Questions Questions Summary Summary Smoke wire Smoke wire Pressure taps Pressure taps Strain Gauges Strain Gauges Accelerometer Accelerometer

Model Testing Suggestions Background Background Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions Modify model as needed Modify model as needed Start testing as soon as possible Start testing as soon as possible Be familiar with theory and equations needed to reduce data Be familiar with theory and equations needed to reduce data

Project Accomplishments Project Objectives Project Objectives Aerodynamic Theory Aerodynamic Theory Model Design Model Design Optional Testing Procedures Optional Testing Procedures Project Accomplishments Project Accomplishments Recommended Future Pursuits Recommended Future Pursuits Summary Summary Questions Questions

Project Accomplishments Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions Project has been advanced over the past four terms Project has been advanced over the past four terms The Active Wing Group (AWG) The Active Wing Group (AWG) Active Wing Technology (AWT) Active Wing Technology (AWT) Active Wing Engineering (AWE) Active Wing Engineering (AWE) ATAK Technologies (ATAK) ATAK Technologies (ATAK)

Active Wing Group Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions Recovered F-111 wing-tail from storage Investigated limit cycle oscillations (LCO) Provided a strong foundation for Summer 2002 project continuation

Active Wing Technologies Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions Primarily Research on F-111 Limit cycle oscillations (LCO) Limit cycle oscillations (LCO) Increasing lift on fighter wings Increasing lift on fighter wings Implementation of control surfaces Implementation of control surfaces Digital and analog control systems Digital and analog control systems

Researched the aerodynamic theory behind oscillating flaps Researched the aerodynamic theory behind oscillating flaps Selected actuation system Selected actuation system Constructed model wing with leading edge flaps Constructed model wing with leading edge flaps Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions Active Wing Engineering

ATAK Technologies Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions Research Research Aerodynamic forces involved in active wing technology Control surface effect on lift Model Design Model Design Actuation system Structure design AutoCAD model Delivered spar design to machinist for construction Delivered spar design to machinist for construction Gathered all necessary model materials. Gathered all necessary model materials. Lab Maintenance Lab Maintenance Worked to clean WRW 316

ATAK Technologies Wing Structure Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions

Recommended Future Pursuits Project Objectives Project Objectives Aerodynamic Theory Aerodynamic Theory Model Design Model Design Optional Testing Procedures Optional Testing Procedures Project Accomplishments Project Accomplishments Recommended Future Pursuits Recommended Future Pursuits Summary Summary Questions Questions

Recommended Future Pursuits Objectives Objectives Theory Theory Model Model Testing Testing Work Work Summary Summary Questions Questions Complete the construction of the wing model Prepare for experimentation using the model Design testing equipment and conditions Place instruments on model design Use LabView software to coordinate data acquisition Conduct experiments using wing model Reduce acquired data and draw conclusions concerning the relationship between frequencies and the desired characteristics.

Presentation Summary Presentation Summary Background Information Background Information Project Objectives Project Objectives Aerodynamic Theory Aerodynamic Theory Modeling and Final Design Modeling and Final Design Proposed Testing Procedures Proposed Testing Procedures Project Accomplishments Project Accomplishments Recommended Future Work Recommended Future Work

References [1]Aguirre, Robert, Thomas Ayers, Kevin Mackenzie, and Vu Tran. “Design and Development of an Active Wing Model.” ATAK Technologies, Austin, TX, Mar [2]Garret, Carlos, Justin Gray, and Kevin Marr. “Design of an Active Controlled Wing Model Using Flap Oscillation.” AWE Engineering, Austin, TX, Dec [3]Fuentes, David, Basil Philips, and Naoki Sato. “Design and Control Modeling of an Active Variable Geometry Wing.” Active Wing Technologies, Austin, TX, Aug [4] Wu, J.M., Wu, J.Z., “Vortex Lift at a Very High Angle of Attack with Massively Separated Unsteady Flow,” Fluid Dynamics of High Angle of Attack, R. Kawamura, Y. Aihara ed., Springer-Verlag, Berlin Heidelberg, 1993, pp [5] Kobayakawa, M., Kondo, Y., Suzuki, H., “Airfoil Flow Control at High Angle of Attack by Surface Oscillation,” Fluid Dynamics of High Angle of Attack, R. Kawamura, Y. Aihara ed., Springer-Verlag, Berlin Heidelberg, 1993, pp

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