Development of flying wing UAVs

University Lower Danube- Center of Excellence in

Research

Reev River Aerospace-Advanced Technology

Research Group

Few historical points

Soviet BICh-3, German Horten H-1,

HO-229

UAV study financed 6 months study by

UK Ministry of Defense 180K USD

Initial designers: Northrop Grumman,

Alexander Lippisch, Horten and

Eshelman

Why flying wings?

Simplicity and robustness

Aerodynamically efficient

Excellent gliding ratios

Maneuverability at a click

Higher and flexible payload capability

Easy operation take-off/flight/landing

No special field take-off/landing field

required

Flying wing headaches?

Sensitive to balancing

Need different airfoils than standard

airplanes

Pusher/Puller motor?

Sweep, geometrical planform, wing

loading vs. speed and wind operation

Phoenix 1-portable mini-UAV

Electric propulsion

Wingspan 1.2m

Payload: 700grame

Max. speed: 100km/h

Max. altitude: 3500m

Autonomy: 40minute

Negligible IR/radar/acoustic signature

Phoenix 2-medium portable UAV Combustion propulsion

Wingspan 1.7m

Payload: 2kg

Max. speed: 220km/h

Max. altitude: 4500m

Autonomy: 60-120minutes

Negligible IR/radar/acoustic signature

Phoenix 3- portable UAV Electric propulsion

Wingspan 2m

Payload: 2.5kg

Max. speed: 80km/h

Max. altitude: 4500m

Autonomy: 45minute

Detachable in 2 segments for easier

transportation

Negligible IR/radar/acoustic signature

Few words on autopilot

Inertial unit; inertial estimation for wind

Dead-reckoning capability for up to 10

minutes- civilian version

Direction angle matrix based

Full PID loops tuned specifically for

each wing

Full control on elevators, throttle and

other 5 different channels (e.g.: camera

axis, zoom etc.)

How does it really work?

0 0.5 1 1.50

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

f

Lambda

alfa=5

alfa=2.5

alfa=1.67

alfa=1.25

alfa=1.0

alfa=Ae/Atk=1.4

kk

k

kk 11

21

1

1

11

2

11

Right member of equation

satisfies: 1d

)(d f

Hence, equation does not converge.

We use Newton-Raphson interative

method:

i

iiii f

f

d

)(d1

)(1

Some more work 1)1()( 211

abcf

12

11111)1(2)(

abcbaf

;

,

Finally an iterative method can be formulated:

12

1111

2

111

1

1

)1(21

)1(a

ii

a

iiii

bcba

bc

ox

m

V

p

V

V

V mbpaVaVox ~~~

ox

mpV mbpaaVa ox ~~

ox

m

p

p

pp

V

p mbpaaVapox ~

~

;

,

Guidance laws in general form:

Example of robustness/fiability

PHOENIX 1 has been operated successfully for ~ 4 years

It has been operated on 3 continents: North America (Louisiana/Florida), Europe (Spain, Romania, Sweeden-Kiruna - past the Arctic Circle), Asia (India)

Temperature and humidity varied greatly during the operation lifetime due to large geographical dispersion (from -30 degrees Celsius to +35-38 degrees Celsius)

Video-On Screen Display

Video is streamed real-time

Flight parameters are: altitude, speed, GPS coordinates, heading/distance to HOME defined base as well as other up-to 8 parameters that can be configured depending on the application

Flight parameters are also shown in real-time with high measurement resolution using advanced Kalman filtering

Ground station

The ground station is portable and can be configured in different modes depending on the operational requirements stated by the client

Rugged/high autonomy tablet PC runs custom designed ground station software that is used for real-time visualization and recording (video & flight data), firmware configuration for on screen display and post-flight analysis of the data

Video receiver with high fidelity antennas package, adapted for the mission, built on two high mobility tripods offers maximum portability for the ground station with minimum deployment time (2-3 minutes). Antennas switching capability can be included for maximum performance.

Standard ground station can be used in high/low temperature and high/low humidity environments. (-30 to +50 degrees Celsius). Extended operation range can be offered.

Ground station- general setup

Advantages of flying wing

airframe

Simple operation: hand launched, landing on natural surfaces (grass, concrete, land etc.), extremely short deployment time

Very simple maintenance

Efficient construction and high robustness together with unequaled low cost (low prices) gives a high quality non-expensive surveillance solution

High portability

High maneuverability for specific missions

High aerodynamic efficiency compared with classical airplane airframe. We use proprietary flying wing airfoils developed in years of theoretical and experimental testing specifically for flying wings

Characteristics:

Visual range and beyond visual range flight (video flight or

flight using a map and autopilot)

Real-time video streaming and recording for fast in-flight

analysis and detailed post-flight analysis

Advanced telemetry system (high performance flight

parameters)

Active stabilization system (UAV is self-stabilized with NO

input from operator)

Auto-pilot for autonomous flight

Flight formations (strong/weak coupled)

Payload and range can be adapted depending on the mission

requirements

Thank you!