Oklahoma Space GrantOklahoma Space Grant
Long Range/Endurance UAV projectsLong Range/Endurance UAV projects
•Started as an OSGC undergraduate workforce project
•Team of 2 aerospace engineering undergraduates (OSGC Fellowship Recipients Dustin Gamble, Thomas Hays)
•Goal was to design a highly efficient electric plane capable of setting FAI world records for range and endurance.
•F5S class: electric aircraft, sub 5kg (11lb), etc.
•Lessons learned to be applied to other industry/research projects
•Students gain valuable hands-on training in UAV’s
BackgroundBackground
Federation Aeronautique InternationaleFederation Aeronautique InternationaleFAIFAI
Sanctions all international aerospaceRecords.
Dragonfly designed for the F5SRecord class.
F5S Requirements:•5 Kg (11.02 lb)•Electric•Maximum surface area 150 dm (16 sq-ft)•Min Surface loading of 12-50 g/dm (.25 lb/sq-ft)•Aircraft must be in sight the entire flight•Must land and takeoff within 500 m of Claimed spot (1640 feet)•Must be observed by FAI official and two additional observers
F5S Duration F5S Range
Duration Record held since 1998: 10 Hours 38 Minutes. (Emil Hilber – Switzerland)
Multidimensional Optimization problem:Span - Area - battery weight - motor size - gearbox ratio - prop size - prop pitch - Battery Voltage.
Endurance vs. Fuel Fraction
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Fuel Fraction
En
du
ran
ce
Maximize battery (fuel) weight
Maximize energy storage density
Minimize structural weight
Maximize aero/propulsive eff.
Minimize systems drain
Endurance ChallengesEndurance Challenges
Difficult constraints (esp. 11lb weight limit)
Primary Design GoalsPrimary Design Goals
Endurance Challenges (cont.)Endurance Challenges (cont.)
High Value Endurance
High L/D Range
CdCl 2
3
Structural Challenges:Structural Challenges:
High aspect ratioThin airfoil section (1 inch)Must absorb atmospheric turbulence (2.7g design)Must be extremely light (.5 lb = 1 hour lost)Maintain accurate shape
Streamlining Streamlining
•Reduce Drag from cross-section of fuselage
•Designed around streamline of SD 7032 airfoil at Duration CL
Blended Wing Body JunctionBlended Wing Body Junction
•Reduces interference drag
•Provides room to store electronics
Power / Energy SourcesPower / Energy Sources::
• Custom Made Lithium Polymer Batteries
• 560 Wh Total energy capacity(equiv to 329 AA batteries) Lithium Polymer:
• Light Weight• Highest Commercially available energy density.
58g motor11g gearbox
•14.5 ft span •3.7 lb weight without “fuel”•7.3 lb. of Lithium Polymer batteries•40 Watt cruise power, 200 Watt peak •Hand-flown, and turned with rudder/dihedral to minimize current draw
Dragonfly
Test flying:Test flying:
• Verify Handling Qualities• Determine actual power consumption• Set limits on flying conditions• Determine how to land
Attempted record during test flight
Used a predetermined route in northern OK
From Kildare to Wakita and back.
144.42 Km = 90 miles
Flew airplane from convertible
Point and Return:Point and Return:
Juri Laidna (Estonia)49 Miles
Dragonfly89 Miles
Dragonfly max range267 Miles
Dragonfly: Point and Return Mission
Launched at sunrise
41 grams underweight
30 minute pilot shifts
Experienced 3G atmospheric turbulence
Judged remaining power through telemetry
Landed with 9 minutes of power remaining.
Duration Record:Duration Record:
Dragonfly: Duration Mission
Most Memorable Most Memorable Aviation Record of 2006Aviation Record of 2006
NAA Luncheon Washington D.C.
National Aeronautic Association:United States’ interface to FAI
Oklahoma State University California State University LA
PterosoarPterosoar(“Winged creature that will rise, fly, or glide high and with little apparent effort”)
•Joint OSGC/CSGC project•2 additional OSU students, and 4 from CSULA•Custom Made PEM Hydrogen Fuel Cell and 4000 psi composite tank• 1.8 x the energy capacity of Dragonfly’s Batteries
• Fully CNC molded Construction• Rapid Design ->Construction -> Test flight (6 weeks)• 4-part design for transportation
Pterosoar Point and Return:Pterosoar Point and Return:
• Distance: 120 Km = 75 miles• Launch from Lancaster, CA• 17 grams of Hydrogen use
Duration Record Attempt is next for The Pterosoar.
Pterosoar: Point and Return
QuestionsQuestions