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