Using Electric UAV sizing Methodology

Philip Asante

Aircraft Aerosonde Aerosonde BSST Observer I Xian ASN-15 Qods Talash Fokker Space MATE NPS Remez-3 Cyberflight CyberOne Cyberflight Swift-Eye

Country Australia China China Iran Netherlands Ukraine United Kingdom United Kingdom

Launch Car Cradle Hand Hand/Rail Conventional Mortar Tube Conventional Conventional Hand

Power(hp) 1 Unknown Unknown Unknown Unknown 2.5 2.5 unknown

Engine 1 cyl; 4-stroke piston 4-stroke piston 1 cyl piston 1 cyl piston Electric 1 cyl piston 1 cyl piston (x2) 1 cyl piston

Range(km) 2778 5 10 8 5 20 32.2 3.2

Endurance(h) 32 1.5 1 0.5 0.5 2 2 1

Cruise spd(kph) 104 120 90 90 Unknown 105 160 153

Loiter(kph) 74 74 56 56 Unknown 58 57 48

Alt Upper (m) 4500 1600 500 Unknown 300 Unknown 6100 4265

Alt Lower (m) 100 200 50 Unknown Unknown Unknown 50 50

We (kg) 8.2 4.2 2 7.1 6 6.5 5.4 1.8

Wo (kg) 13.4 10 6.5 12 6 10 12.2 6.4

We/Wo 0.611940299 0.42 0.307692308 0.591666667 1 0.65 0.442622951 0.28125

• 8 UAV’s Studied Selected for Greater Study.

•Weight and Endurance were of Particular Interest.

•Found that UAV’s of this size usually use Piston Engines.

Philip Asante

Pusher Motorc

H-Tail Configuration

Camera Dome

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T-Tail configuration

Mounted pusher motor and fairing

High wing for increased roll stability

Philip Asante

Philip Asante

Philip Asante

Similar Design Used By Highlighted UAV’s of Similar Weight.

Good Low Speed Flight Stall and Stability Characteristics. (Tail Wing Will not stall Due to Prop Airflow.

Philip Asante

Philip Asante

Wtakeoff = Wstruc + Wpayload + WBattery+ WMotor+ Welec

•Structure Weight Typically between 25-30% of the Take-Off Weight.

•US Airforce Cadets in the Aerospace Program use a wing loading contribution of 0.2 lb/ft^3 for their UAV Designs.

•Fair assumption When using Carbon Fiber and Epoxy Composite Skin over a Styrofoam Core.

Philip Asante

0

2

4

6

8

10

12

14

16

0 2 4 6 8 10

Take-O

ff W

eig

ht

Empty Weight

Take-off Weight vs Empty Weight Trend

Series1

Log. (Series1)

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High Definition TV Camera and/or IR Sensors

Video Downlink Communication Package

Motor

Above Payloads Included in Research Weight

Extra Battery for Avionics and Camera?

Sensitivity Study To be Conducted to see effect of Payload weight changes

Philip Asante

Wetted Area Estimate = 10.87 units^2

Reference Area=3.42 units^2

Wing Span = 5.7 units

A.R. = 2.9

L/Dmax = 13.5

L/D cruise = 13.5 (for prop)

L/D cruise = (0.866)(13.5)=11.691

Philip Asante

Climb important in determining Battery Weight

Climb to 500 ft

Climb

Cruise Cruise

Loiter

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Calculated as a Function of L/D ratio.

Energy Density of Li-Ion Battery (0.46 MJ/kg)

Assumed Motor and Prop Efficiency (0.8)

Calculated Estimate of 2.03 kg

Philip Asante

USAF Academy Estimates 0.2 lb/ft^2

Assumed Nominal for Aircraft using Carbon Fiber and Epoxy Composite skin Over Styrofoam Core.

Expect Structural Weight of 0.97 kg/m^2 of referemce area.

Philip Asante

Propulsion Method

Philip Asante

Battery Sizing Explained Further

•D-Drag Force, estimated from Obtained L/Dmax and aircraft weight of 8 kg•V- Aircraft Speed•t- Total Desired Flight Time•(|)- Energy Density of Lithium Ion Battery•Motor and Prop Efficiencies. (0.8 for motor and 0.7 for prop)•Divided by reference area to obtain wing-loading contribution.

Philip Asante

Battery Weight Sensitivity

0

1

2

3

4

0 5 10 15

Lif

t

Drag

Drag Sensitivity

Drag Sensitivity

0

0.5

1

1.5

2

2.5

3

0 20 40

Speed Sensitivity

Speed Sensitivity

0

1

2

3

4

0 5000 10000

Endurance Sensitivity

Endurance

Sensitivity

•1N increase = 0.35 kg

•5 m/s= 0.081196 kg

•Every Half Hour = 0.016916 kg

Philip Asante

Maximum Takeoff Weight Calculation

Wtakeoff /s= Wstruc /s + Wpayload /s + WBattery /s + WMotor /s + Welec /s

Wtakeoff /s = 52.67 N/m^2 (Obtained from constraint diagramand typical for UAV’s of this size)

Wstructure /s= 9.58 N/m^2

Philip Asante

Calculating Wing Reference Area

Wetted Area Estimate = 10.87 units^2

Reference Area=3.42 units^2

Wing Span = 5.7 units

A.R. = 2.9

L/Dmax = 13.5

L/D cruise = 13.5 (for prop)

L/D cruise = (0.866)(13.5)=11.691

Philip Asante

Motor Wing Loading ContributionSpecifications:•Weight 58g including motor mount.9 T, 23AWG, DLRK, delta, 14 Magnet poles.•Shaft 3mm•No load 13200 RPM, 10.06V, 1.22A.28 AMP Max continuous.33 AMP Max Burst.

Prop and Thrust:GWS 12x8 APC E Propeller

Drag force calculated based on L/D and an aircraft of 8kg and used to determine motor Prop/Motor combination

13.4 N of Thrust With Selected combination

Philip Asante

Next Step

•Create Program That adjusts Take-off Weight and Wingspan w.r.t. Payload mass.

•Prepare concept structural design proposal

•Perform stability and control analysis

Philip Asante