Control of Tailless
Morphing Aircraft

Office of Naval Research - Young Investigator Program Award

June 2018 - May 2022

$510,000

Project Overview

The next generation of fighter aircraft will be tailless. One significant challenge that must be addressed in order to make this a reality is yaw control. The present work considers the use of morphing technology to produce sufficient roll, pitch, and yaw control for tailless aircraft. The overall hypothesis is that the fundamental relationships between aerodynamics and wing morphology can be exploited to produce adequate longitudinal and lateral control for tailless aircraft.

Objectives

Identify relationships between wing morphing and aerodynamics of tailless aircraft
Characterize the morphing input parameters that produce desired control outputs
Assess the accuracy of the predicted relations
Evaluate the control relationships on a full free-body dynamic system

Statistics

11 Students
7 Journal Publications
119 Journal Publication Pages
15 Conference Papers
15 Conference Presentations
3 PhD Dissertations
3 MS Theses
4 Public Software Packages on Github
2 Publicly Available Aircraft Designs
100+ Student/Advisor Meetings
49,000+ Lines of Code

18 Morphing-Wing Concepts

194 Morphing-Wing Prototypes
10,000+ Hours of 3D printing
100+ kg PLA
13 Fully 3D Printed Airframes
8 Take Offs
2 Purposeful Landings
2 Follow On studies
- NSF flutter study
- BIRE flight test portion

Final Presentation Recordings

1- Introduction

2- Lift Distributions

3- Analytic Roll/Yaw Control

4- Aileron Placement

5- Swept and Crescent Wings

6- Lifting-Line Algorithm for Wings with Sweep

7- MachUp X

8- Morphing Wing Design

9- Manufacturing and Assembly

10- Aircraft Checkout

11- Control Mapping

12- Flight Testing

13 - Recap

Full Presentation Playlist

Publications

Journal Publications

Modern Implementation and Evaluation of Lifting-Line Theory for Complex Geometries

Goates, C., and Hunsaker, D. F., “Modern Implementation and Evaluation of Lifting-Line Theory for Complex Geometries,” Journal of Aircraft, In Review

Accuracy of Küchemann's Prediction for the Locus of Aerodynamic Centers on Swept Wings

Moorthamers, B., and Hunsaker, D. F., “Accuracy of Küchemann's Prediction for the Locus of Aerodynamic Centers on Swept Wings,” The Aeronautical Journal, April 2022, 21 pages, DOI: 10.1017/aer.2022.34.

Minimum-Series Twist Distributions for Yawing-Moment Control During Pure Roll

Hunsaker, D. F., Moorthamers, B., and Joo, J., “Minimum-Series Twist Distributions for Yawing-Moment Control During Pure Roll,” Zeitschrift für Angewandte Mathematik und Mechanik, May 2021, 19 pages, DOI: 10.1002/zamm.201900177

Aileron Size and Location to Minimize Induced Drag During Roll Initiation

Brincklow, J., and Hunsaker, D. F., “Aileron Size and Location to Minimize Induced Drag During Roll Initiation,” The Aeronautical Journal, Vol. 125, No. 1287, 2021, pp. 807–829, DOI: 10.1017/aer.2020.139

General Approach to Lifting-Line Theory, Applied to Wings with Sweep

Reid, J. T., and Hunsaker, D. F., “A General Approach to Lifting-Line Theory, Applied to Wings with Sweep,” Journal of Aircraft, Vol. 58, No. 2, 2021, pp. 334-346 DOI: 10.2514/1.C035994

Adverse-Yaw Control During Roll for a Class of Optimal Lift Distributions

Hunsaker, D. F., Montgomery, Z. S., and Joo, J. J., "Adverse-Yaw Control During Roll for a Class of Optimal Lift Distributions," AIAA Journal, Vol. 58, No. 7, pp. 2909-2920, 2020, DOI: 10.2514/1.J059038

Minimising induced drag with weight distribution, lift distribution, wingspan, and wing-structure weight

Phillips, W. F., Hunsaker, D. F., and Taylor, J. D., "Minimising induced drag with weight distribution, lift distribution, wingspan, and wing-structure weight," The Aeronautical Journal, Vol. 124, No. 1278, pp. 1208-1235, 2020, DOI: 10.1017/aer.2020.24

Designing Wing Twist or Planform Distributions for Specified Lift Distributions

Phillips, W. F. and Hunsaker, D. F., "Designing Wing Twist or Planform Distributions for Specified Lift Distributions," Journal of Aircraft, Vol. 56, No. 2, pp. 847-849, 2019, DOI: 10.2514/1.C035206

Conference Publications

Control Mapping Methodology for Roll, Pitch, and Yaw Control on Morphing-Wing Aircraft

Montgomery, Z., and Hunsaker, D. F., “Control Mapping Methodology for Roll, Pitch, and Yaw Control on Morphing-Wing Aircraft,” AIAA SciTech Forum, January 2022, AIAA-2022-2531, DOI: 10.2514/6.2022-2531

Design and Performance of a 3D-Printed Morphing Aircraft

Snow, S. A., and Hunsaker, D. F., “Design and Performance of a 3D-Printed Morphing Aircraft,” AIAA Scitech Forum Virtual Event, January 2021, AIAA-2021- 1060 DOI: 10.2514/6.2021-1060

Link to Video Presentation

3D-Printed Wings with Morphing Trailing-Edge Technology

Moulton, B. C., and Hunsaker, D. F., “3D-Printed Wings with Morphing Trailing-Edge Technology,” AIAA Scitech Forum Virtual Event, January 2021, AIAA-2021-0351 DOI: 10.2514/6.2021-0351

Link to Video Presentation

Controlling Roll-Yaw Coupling with Aileron Placement and Wing Twist

Brincklow, J. R., Montgomery, Z. S., and Hunsaker, D. F., "Controlling Roll-Yaw Coupling with Aileron Placement and Wing Twist," AIAA SciTech Forum Virtual Event, January 2021, DOI: https://doi.org/10.2514/6.2021-0327

Link to Video Presentation

Sensitivity and Estimation of Flying-Wing Aerodynamic, Propulsion, and Inertial Parameters Using Simulation

Thurgood, J. W., and Hunsaker, D. F., "Sensitivity and Estimation of Flying-Wing Aerodynamic, Propulsion, and Inertial Parameters Using Simulation," AIAA SciTech Forum Virtual Event, January 2021, AIAA-2021-1528, DOI: 10.2514/6.2021-1528

Link to Video Presentation

Estimation of Incompressible Swept-Wing Aerodynamics Using Low-Fidelity Methods

Moorthamers, B., Wiberg, D., and Hunsaker, D. F., "Estimation of Incompressible Swept-Wing Aerodynamics Using Low-Fidelity Methods," AIAA SciTech Forum Virtual Event, January 2021, AIAA-2021-1825, DOI: 10.2514/6.2021-1825

Practical Implementation of a General Numerical Lifting-Line Method

Goates, C., and Hunsaker, D. F., "Practical Implementation of a General Numerical Lifting-Line Method," AIAA SciTech Forum Virtual Event, January 2021, AIAA-2021-0118, DOI: 10.2514/6.2021-0118

Optimization of Ailerons to Minimize Induced Drag in Roll

Brincklow, J. R., and Hunsaker, D. F., “Optimization of Ailerons to Minimize Induced Drag in Roll,” AIAA Scitech Forum, Orlando, Florida, January 2020, AIAA-2020-0279, DOI: 10.2514/6.2020-0279

Accuracy of Küchemann's Prediction for the Locus of Aerodynamic Centers on Swept Wings

Moorthamers, B., and Hunsaker, D. F., “Accuracy of Küchemann's Prediction for the Locus of Aerodynamic Centers on Swept Wings,” AIAA Scitech Forum, Orlando, Florida, January 2020, AIAA-2020-0533 , DOI: 10.2514/6.2020-0533

Ludwig Prandtl’s 1933 Paper Concerning Wings for Minimum Induced Drag, Translation and Commentary

Hunsaker, D. F., and Phillips, W. F., “Ludwig Prandtl’s 1933 Paper Concerning Wings for Minimum Induced Drag, Translation and Commentary,” AIAA Scitech Forum, Orlando, Florida, January 2020, AIAA-2020-0644 , DOI: 10.2514/6.2020-0644

Control of Adverse Yaw During Roll for a Class of Optimal Lift Distributions

Hunsaker, D. F., Montgomery, Z. S., and Joo, J. J., “Control of Adverse Yaw During Roll for a Class of Optimal Lift Distributions,” AIAA Scitech Forum, Orlando, Florida, January 2020, AIAA-2020-1264, DOI: 10.2514/6.2020-1264

A General Approach to Lifting-Line Theory, Applied to Wings with Sweep

Reid, J. T. and Hunsaker, D. F., “A General Approach to Lifting-Line Theory, Applied to Wings with Sweep,” AIAA Scitech Forum, Orlando, Florida, January 2020, AIAA-2020-1287, DOI: 10.2514/6.2020-1287

Minimizing Induced Drag with Weight Distribution, Lift Distribution, Wingspan, and Wing-Structure Weight

Phillips, W. F., Hunsaker, D. F., and Taylor, J., “Minimizing Induced Drag with Weight Distribution, Lift Distribution, Wingspan, and Wing-Structure Weight,” AIAA Aviation Forum, Dallas, Texas, June 2019, AIAA-2019-3349, DOI: 10.2514/6.2019-3349

Effects of Sweep on Airfoil Section Properties

Reid, J. T., and Hunsaker, D. F., “Effects of Sweep on Airfoil Section Properties,” AIAA Aerospace Sciences Meeting, San Diego, California, January 2019, AIAA-2019-2118, DOI: 10.2514/6.2019-2118

Aerodynamic Center at the Root of Swept, Elliptic Wings in Inviscid Flow

Moorthamers, B., and Hunsaker, D. F., “Aerodynamic Center at the Root of Swept, Elliptic Wings in Inviscid Flow,” AIAA Aerospace Sciences Meeting, San Diego, California, January 2019, AIAA-2019-0032, DOI: 10.2514/6.2019-0032

Theses / Dissertations

Control Mapping Methodology for Tailless Morphing-Wing Aircraft

Zach Montgomery

PhD Dissertation

2022

A Study of Wings with Constant and Variable Sweep for Aerodynamic Efficiency in Inviscid Flow

Bruno Moorthamers

PhD Dissertation

2021

3D-Printed Morphing Wings for Controlling Yaw on Flying-Wing Aircraft

Ben Moulton

MS Thesis

2021

Sensitivity and Estimation of Aerodynamic, Propulsion, and Inertial Parameters
for Rudderless Aircraft Using Simulation

Jaden Thurgood

MS Thesis

2021

A General Approach to Lifting-Line Theory,
Applied to Wings with Sweep

Jackson Reid

PhD Dissertation

2020

Optimization of Aileron Spanwise Size and Shape
to Minimize Induced Drag in Roll with Correlating Adverse Yaw

Josh Brincklow

MS Thesis

2020

Software Packages

Open Aircraft Designs

Manta

4-ft 3D Printed Flying-Wing Aircraft with traditional ailerons

Horizon

10-ft 3D printed Flying-Wing Aircraft with 11 conformal flaps

Aircraft Design, Print, and Assembly

Conformal Flap Design and Prototyping

Many videos available here.

Final Conformal Flap Design

Horizon Airframe 3D Printing Time Lapse

Horizon Airframe Assembly Time Lapse

Flight Testing

Flight-Test Checklist

Flight-Test Folder

Glide Test

April 15, 2021

Purpose: To test the following:

static longitudinal and lateral stability
CG location

Outcome: Successful glide test. CG location seems to produce adequate static stability.

1st Powered Test

May 3, 2021

Aircraft: V3

Purpose: Test the following:

Structural design
Controllability using Mode 1 (Safety mode with pure elevons)
Adequacy of the ducted fans for propulsion

Outcomes: Aircraft exhibited aeroelastic behavior with repeated instances of intermittent flutter (see t=1.25 min). Test ended with catastrophic flutter event at t=2:10 min. Controllability difficult to discern due to flutter. Ducted fans produced less thrust than expected. Trim required a throttle setting of about 75%.

Flight Time: 00:01:49

2nd Powered Test

June 29, 2021

Aircraft: V4

Purpose: Test the following:

Improved structural design with added carbon-fiber reinforcement in spar caps
Controllability using Mode 1 in the absence of flutter events
Adequacy of the ducted fans for propulsion with new ESC

Outcome: Aircraft sufficiently rigid. No flutter issues. Trim required less throttle (about 66%) most likely due to new ESC. Flight test routine and documentation greatly improved. Dutch roll not as damped as desirable for good handling qualities (see t=4:57 in video). Intermittent loss of signal between receiver and transmitter caused intermittent pitch pulses throughout flight (see t=2:07). Loss of signal eventually lead to catastrophic loss of control (see t=5:16). Loss of signal most likely due to a loose connection on the receiver.

Flight Time: 00:04:18

3rd Powered Test

October 7, 2021

Aircraft: V6 M2

Purpose: Test the following:

Improved design of center-section conformal flap
Data acquisition with Pixhawk 4
Controllability in Mode 2
Determine ranges of CL, pbar, Cm, and Cn commanded by pilot during a nominal flight
(Secondary) Evaluate deflections from video compared to commanded deflections

Outcome: Crash on takeoff. Video and other data used for crash analysis.

Flight Time: 00:00:06

4th Powered Test

November 4, 2021

Aircraft: V7 M2

Purpose: Test the following:

Improved launch methodology
Improved design of center-section conformal flap
Data acquisition with Pixhawk 4
Controllability in Mode 2
Determine ranges of CL, pbar, and Cm commanded by pilot during a nominal flight
(Secondary) Evaluate deflections from video compared to commanded deflections

Outcome: Clean launch. Stable with plenty of power. Center section conformal flap checks out. Sufficient data collected to test ranges of pbar and Cm commanded by pilot. Aircraft felt sluggish in the air. Motors sputtered and servos froze in air repeatedly. Could be due to loss of signal. This behavior caused final crash.

Flight Time: 00:03:00

5th Powered Test

April 27, 2022

Aircraft: V8 M2

Goals:

Clean Launch
Zero drops in communication
Test Mode 2
Purposeful Landing

Outcome: Clean launch. Stable with plenty of power in Mode 1. Zero drops in communication. When switching to Mode 2, the aircraft was trimmed (from Mode 1) with pitch up. The aircraft pitched up as it entered Mode 2 and entered a glide slope that could not be shaken. Hard landing, but with wings level.

Flight Time: 00:01:32

6th Powered Test

May 23, 2022

Aircraft: V9 M2

Goals:

Clean Launch
Zero drops in communication
Test Mode 2
Purposeful Landing

Outcome: Issue during launch. Launch mechanism wrapped around wing. Wing snapped due to possible faulty construction.

Flight Time: 00:00:02

7th Powered Test

June 6, 2022

Aircraft: V10 M2

Goals:

Clean Launch
Zero drops in communication
Test Mode 2
Purposeful Landing

Outcome: Nearly perfect flight. Clean launch. Grazed the ground a little close to the bungee stakes during launch. Solid flight. Spent 2 minutes 12 seconds in Mode 2. Firm touch down broke up the aircraft.

Flight Time: 00:04:36

8th Powered Test

June 9, 2022

Aircraft: V11 M2

Goals:

Clean Launch
Mode 4 Yaw Control
Successful Landing

Outcome: Beautiful launch. Clean transition from Mode 1 to Mode 4. Successful turn in Mode 4. Tested right and left yaw command. Flutter event caused aircraft to break up in the air.

Flight Time: 00:02:29

Annotated Yaw Control and Flutter Event