Black Bird Uav Initial Sizing Methadology
- 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
- 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
- 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