The document discusses electric UAV sizing methodology by studying 8 existing UAVs. Key factors like weight, endurance, and power source were analyzed. It was found that piston engines are commonly used for UAVs of similar size. The document then examines design considerations for an electric UAV like wing configuration, motor and battery sizing calculations, and structural weight estimates to determine maximum takeoff weight. Next steps proposed include an optimization program to adjust design based on payload mass and performing stability and control analysis.

1. Using Electric UAV sizing Methodology
Philip Asante

2. • 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.
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
Philip Asante

3. Pusher Motorc
H-Tail
Configuration
Camera
Dome
Philip Asante

4. T-Tail
configuration
Mounted pusher
motor and fairing
High wing for
increased roll
stability
Philip Asante

5. Philip Asante

6. Philip Asante

7.  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

8. Philip Asante

9. 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

10. Take-off Weight vs Empty Weight Trend
16
14
12
Take-Off Weight
10
8
Series1
6
Log. (Series1)
4
2
0
0 2 4 6 8 10
Empty Weight
Philip Asante

11.  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

12.  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

13. Cruise Cruise
Climb to Climb
500 ft Loiter
 Climb important in determining Battery
Weight
Philip Asante

14.  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

15.  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

16. Propulsion Method
Philip Asante

17. 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

18. Battery Weight Sensitivity
Speed Sensitivity
Drag Sensitivity
3
4
2.5
3
2
2
Lift
1.5
1 Speed Sensitivity
1
Drag Sensitivity
0 0.5
0 5 10 15 0
0 20 40
Drag
Endurance Sensitivity
4 •1N increase = 0.35 kg
3
2 Endurance •5 m/s= 0.081196 kg
1 Sensitivity
0
•Every Half Hour = 0.016916 kg
0 5000 10000
Philip Asante

19. 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

20. 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

21. Motor Wing Loading
Contribution
Specifications:
•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

22. 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