A High Altitude Inflatable -Winged Aircraft
Baseline Balloon Inflatable Launch Glider Unmanned Experiment
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UK BIG BLUE Team
• Student team leaders – Justin Kearns, Overall Team and Mechanical Engineering Technical Lead – Mike Carter, Project Manager – Aaron Welch, Electrical Engineering Technical Lead • Advisors – Dr. Suzanne Weaver Smith, Principal Investigator and System Integration – Dr. Jamey Jacob, Aeronautics – Dr. William Smith, Communications and Power – Dr. James Lumpp, Flight Control and Power • 12 Subsystem Components – 42 ME, ECE, and CS undergraduate students; 1 ME graduate student
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1 BIG BLUE Objectives
• To test the performance of inflatable-rigidizable wings in high altitude conditions, including two launch experiments:
– 1st launch with stowed wings, deployed and cured at altitude – 2nd launch with ground-cured wings of ideal shape • Also allows for fallback position if in the event BIG BLUE encounters a technical problem
• To gain valuable student exposure of working in the Aerospace Industry
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The General Plan
• Phase 1 and 2: 1.6 hour ascent at a constant rate of 980 ft/m to 98k ft
• Phase 2 begins prior to balloon release
• Phase 3: 2.5 hour descent
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2 BIG BLUE Glider • Glider specifications: – Total weight: 14.975 lbs. – 6’ wingspan, 12” chord length, 1.2” maximum wing thickness, 10º dihedral – 5’ overall length – Square fuselage design – Foam and balsa laminated tail control surfaces • Glider Capabilities: – Camera, internal wing pressure, temperature, atmospheric pressure, positioning for monitoring and data • Ambient Conditions collection – Temperature: 60ºF (max @ CO elevation) / -94ºF (min) – Uplink/Downlink for positioning, – Pressure: 14.7 psi (max @ CO elevation) / 0.15 psi (min) commands, data collection, and – Density: 0.0768 lb/ft3 (max @ CO elevation) / 0.00128 monitoring lb/ft3 (min) – Autopilot to control flight
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Edge of Space Sciences (EOSS)
– A Colorado based non-profit organization that explores frontiers in amateur radio and high altitude ballooning
– First flight in 1990
– EOSS has grown in volunteer membership numbers and skills over the course of more than 60 successful launches
– Today, it is widely recognized as one of the premier organizations in its field
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3 Edge of Space Sciences (EOSS)
• Launch date set for May 3/4, 2003
• Interfacing document provides a formal agreement to the way in which we interface mechanically and electrically
– Cut-down device actuated by an uplink command code
– EOSS / UK transmission frequencies coordination
– 7 lbs. combined EOSS payloads
– 13 lbs. BIG BLUE glider (15 lbs. max)
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Team Organization
Structural / Wing Design Wing Deployment Data Acquisition Integration
RF/Digital Power Flight Control I Flight Control II Communications
Launch / Recovery Outreach / Avionics and Control Risk Mitigation EOSS Flight Watch
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4 Budget & Schedule
J. Michael Carter BIG BLUE Program Manager
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Budget & Funding
• NASA - The Work Force Development Program awards grants to state Space Grant Consortia to generate interest in aerospace related fields. • Kentucky Space Grant Consortium funds BIG BLUE. • EPSCOR is also helping fund BIG BLUE • UK V.P. of Research
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5 Project Timeline
• Critical Design Review, March 7: BIG BLUE team members will meet with ILC Dover, Inc. • Spring Break, March 15-23: Working period for beginning final construction. • Flight, May 3: Denver, CO with E.O.S.S. Inflatable wing flight.
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Wing Design
Michiko Usui Dr. Jamey Jacob
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6 Objectives
•Short Term Goals - determine aerodynamic characteristics of inflatable wing (Cl, Cd, Cm) at required Re - determine if any immediate modifications (such as skinning and/or flaps) need to be made
• Long Term Goals - codify force/moment relations of "inflatable" airfoil profiles over a wide range of Re - investigate separation behavior pre- and post-stall - determine boundary-layer character at low, moderate, and high Re
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Approach
• Select the airfoil which works under low Reynolds number condition (range of 50,000 ~ 200,000)
• Analyze the selected airfoil using available software: – Aerodynamic analysis (Xfoil 6.9) – Finite element analysis (ANSYS 6.1)
• Conduct wind tunnel testing to obtain the aerodynamic performance of the inflatable (“bumpy”) wing and ideal E398 wing
• Verify the wind tunnel data
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7 Airfoil Selection
• From Airfoil Coordinate database of University of Illinois at Urbana- Champaign, five low Reynolds number airfoils were selected (DAE11,DAE31,E387,E398,S7012)
• Xfoil, aerodynamic analysis software, was used to obtain the aerodynamic performance of these airfoils under various Re numbers (Range of 60,000 ~ 500,000)
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Airfoil Selection
• Ranking of airfoils under across the Re range based on aerodynamic performance:
1. E387 2. S7012 3. DAE31 4. E398 (BIG BLUE AIRFOIL) 5. DAE11
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8 Stress Analysis
• Finite element analysis was conducted to determine the maximum stress which occur under following condition: – Re 24,000 – Altitude 98,000ft
• Material of the wing: – S-2 glass fabric (Woven composite) • Thickness, 0.009in • Result: – For one layer, the maximum stress was 10.3ksi – For two and three layers , 4.9ksi and 3.3ksi • Final wing is using two layers of E-glass fabric which has thickness of 0.005in
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Effect of Surface Roughness on L/D as f(Re)
Range of operation
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9 Wind tunnel testing
• Wing Models – UK stereo-lithography lab created the two types of wing from the selected airfoil – Chord length is 12in and wingspan is 24in (chord is full-scale of prototype)
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Wind tunnel testing
• Prototypes then tested in the UK low- turbulence wind tunnel • Tunnel test section: – 24’’x 24’’ cross section – 48’’ length • 50-hp motor drives 50ms with free- stream turbulence levels less than 12% • Tests were conducted over the Re range of 50,000 ~ 200,000 and various range of angle of attack • Type of testing: – Smoke-Wire Flow Visualization – Lift and Drag measurement – PIV, Particle Image Velocimetry
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10 Smoke-Wire Flow Visualization
• Flow Visualization is by the smoke wire technique – As described in Batill and Mueller (1981) – A wire doped with oil is stretched across the test section – The wire is heated by Joule heating and the oil evaporates making smoke trails – Limited to low Re;examined from 25,000 to ,200,000 over a range of angle of attack
Ideal shape wing, Re 50,000 α=0 ° “bumpy” wing, Re 50,000 α=0 °
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Flow Visualization
• Comparison at AoA=0o, Re=50,000
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11 Flow Visualization
• Comparison at AoA=12o, Re=50,000
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Flow Visualization
• Comparison at AoA=0o, Re=25,000 and 100,000
Re=25,000
Re=100,000
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12 Lift and Drag
• Starting from scratch! • New wind tunnel; old balance refurbishment became part of project: – Rewired strain gages – Replaced conditioner – Low-pass band filter was added to the system to eliminate the noise – Force calibration was made – Still in progress…
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Lift and Drag
• Re=156,000: Clmax = 1.33,
L/Dmax= 23
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13 Lift and Drag
• Stall behavior; stall not seen at max. AoA achievable, but pre-stall evident through vortex shedding
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Verification
• Wind tunnel tests will be verified with the XFoil data for test airfoil
• XFoil results of different airfoils (e387 and s7012) was compared with the data given by University of Illinois at Urbana- Champaign (UIUC data was obtained thru website: http://www.aae.uiuc.edu/mselig/uiuc_lsat.html)
• Results compare very favorably
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14 Discussion & Further Work
• E398 selected out of 5 candidate airfoils due to manufacturing considerations
• Inflatable version of the E398 performs better at low Re than the “smooth” E398 due to the ribs from baffles; significant separation still seen at low Re
•Further work – Continuing lift and drag measurements – PIV measurements over upper surface
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WING DEPLOYMENT
• ME 412 Senior Design Group • Team Leader: Colin Goggin • Team Members: Aaron Welch, Nathan Shewmaker
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15 Objectives
• Investigate best method for high altitude deployment of stowed inflatable wing – Considerations include reliability, simplicity, weight, and power • Design and fabricate an inflation subsystem that can work on BIG BLUE glider platform with ILC UV curable wings • Verify that the chosen design will work at altitude, with the UV curable wing set, and within other pertinent design parameters – Optimize for desired inflation rate
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Design - Plenum • Initial plenum for mounting of UV curable wing set by ILC (flight ready plenum will trim mass and include wing dihedral)
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16 Design – Inflation System
• Design Criteria – 10 to 15 second inflation time – Maximum of 7 psig for UV curable wing set – Robust design – Lightweight and compact design – Small power requirement
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Finalized Design
• Pressure Vessel with fill valve, pyro valve, pressure regulator – Relief valve and vent valve on plenum
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17 Finalized Design
• Spherical Pressure Vessel of 35 in3 • Pressurized to ~ 50 psi – This calculation takes into account the loss of pressure with altitude ( approximately 8.7 times lower ) – This results in a inflation rate of 139 in3/sec • Total weight of subsystem components (estimate):
Plenum 0.80 lb Pyro V. .35 lb Tubing 0.026 lb Relief V. (2) 0.04 lb Wiring 0.008 lb Regulator V. 0.08 lb Wing Set 3.0 lb TOTAL 4.304 lb
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Finalized Design
• Power Consumption should be negligible – Squib charge in pyro valve requires very little power ( 1 mA current draw)
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18 Design Alternatives
• Both chemical reaction and solid sublimation techniques were considered – Attractive due to small payload weight – Complicated • Interactions (heat and moisture possible) with deployed wing at altitude – Study of previous experiments suggests solid sublimation is questionable in terms of reliability
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Verification
• Vacuum Chamber to simulate conditions @ 50K ft.
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19 Verification
• Testing in vacuum chamber to begin as soon as chamber is fully equipped for experiments – Testing begins next week (3/10) • Vacuum chamber tests will give an idea of the correct pressure regulator setting for desired inflation rate and duration • Tests will verify the subsystem design as suitable for at altitude deployment – Initially performed on FASM wing setup
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Primary Risks / Mitigation
• Robust design is desirable – Reliability is key for wing deployment subsystem – Pyro valve meets this requirement • Crushing of the wings during descent a concern – This can be addressed with release valve
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20 Structural Design/Integration
ME 380 Aircraft Design Michael Carter Colin Goggin Dustin Hanna Mandy Hart Ronald Humphrey
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Objectives
• Design a plane and fuselage around the fixed wing parameter. – Design control surfaces (horizontal and vertical stabilizer) to allow stable and controllable flight. – Design for desired flight characteristics. – Layout fuselage to house all communications equipment, controls, expansion tank, stowed wings, etc. – Construct models and test designs. • Design a parachute system necessary for safety purposes and to recover the plane intact. – Perform ground tests of parachute system.
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21 Tail Surfaces • Design parameters – NACA 0012 symmetrical airfoil. – Inverted T-Tail: Low Reynolds number flight. NASA Langley. – Oversized components for stability. • Horizontal Volume ratio: 1.2 • Vertical Volume ratio: 0.07 • V=lS/bS – Low weight • Tail sizing – Horizontal Tail: cord=12, b=24 – Vertical Tail: cord=12, b=0 – [Moment] cg to quarter cord: 38” • Construction – Foam laminated with Balsa and Monokote • Interface with Flight Control II
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Forward Velocity & Sink Rate (Analytical) • Find forward velocity at maximum aerodynamic efficiency for best range • Find minimum forward velocity to find minimum sink rate (76% of max L/D velocity) tanθ = L /D
tanθmin =1/(L /D)max
2W V = K forward min sink 3C ρS Do
Vdescent mink sink = Vforward min sink sinθ
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22 Forward Velocity & Sink Rate (Wind Tunnel)
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Time to Descend
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23 Re & Mach Nos.
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Parachute • Parachute will open in the event of failure or at specified elevation for a “soft” landing. • Chute will be ejected with an explosion. • Chute will be selected based on payload (15 lbs) and maximum force. • Components: charge, igniter, blast shield, chute, shock cords, housing. • Overall parachute system dimensions to be determined.
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24 Weight Distribution
Component Weight (lb) X (in) Y(in) Moment about CG
Center of Gravity 19
Wings 3 18 -3
Wing Deployment 1.3
Power and Comm. Batteries 2 4 -30 Other equipment 1.75
Autopilot 0.625
Data Acquisition 1.25
Flight Controll 0.3 Notes: Structural •CG is approximately 10% past quarter cord. Fuselage 218 -2 Tail assembly 1.25 56 46.25 •Fuselage Dimensions: 5x5x36 (Estimate) Parachute system 1.5
Weight (lb) Moment about CG Total 14.975 11.25
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Working Design
•Overall Length: 5’ (target) •Dihedral: 8-15 degrees •Maximum weight: 15 lbs
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25 Testing • Build, test, crash, test, verify, build, FCII test…
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Continuing Progress
•Design – Finalize Angle of Attack – Finalize wing dihedral – Select Fuselage material – Continue evaluating and finalize performance calculations – Lay out internal components – Weight considerations •Testing – Purchase and test parachute system – Fly test plane from higher elevation – Build additional test platforms
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26 Data Acquisition
Charlie Thomson - Team Leader Justin Kearns Matt Branham Joe Newkirk
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Main Objectives
• Data Correlation (Evaluate Flight Performance) • Obtain flight performance from GPS, AHRS, temperature sensors, pressure sensors, air speed indicator • Correlate this performance data with wing shape from cameras • Instrumentation • Identify types and models of instruments being used
• Limitations of the instruments
• Curing • Identify cure time of the wings upon deployment at altitude • Correlate wing stiffness to cure time
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27 Data Analysis and Correlation
• Internal Wing Pressure via pressure sensors • Atmospheric pressure via altimeter • Temperature via temperature sensors • Glide Angle via AHRS • Rate as the glider executes a maneuver via AHRS • Velocity via Latitude and Longitude received from the GPS • Lift/Drag through glide slope angle and airspeed Instrumentation systems crosscheck each other for redundancy and accuracy
• Flight performance obtained above will be correlated with 3-D wing models (Photomodeler) via collected camera data
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Instrumentation
• HOBO H08-006-004 Data Logger – 4 Blank Channels (1 Internal temperature, 2 Internal wing pressure) – Operating range: -4°F to 158°F (-20°C to 70°C) • HOBO TMC1-HA Temperature Sensor – Input into HO8-006-004 Data Logger, Measures Internal Temperature • 2 Pressure Sensors (Mouser 15 PSI-G-4V-MIL) – Temperature Compensated for -40°F to 257°F (-40°C to 125°C) – Measures 0-15 psig – Input into H08-006-004 Data Logger • HOBO Type T Data Logger – TC6-T Temperature Probe Connected, Measures Ambient Temperature – Operating range: -330°F to 356°F (-200°C to 180°C) • 5 BENQ DC300 mini Digital Cameras • Total Power Draw: 3.05 W (2 A @ 1.5 V; 10 mA @ 5 V) • Total Weight: 20.5 oz.
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28 Instrumentation Layout
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Camera Set-up
• EOSS ATV with real-time down-link allows look- down view of aircraft • provide redundancy if in the event of communication or power loss to BIG BLUE system
• 5 digital cameras • 2 orthogonal viewing each wing (4 total) • Saved to memory on-board • ¼”Ø tracking dots for maximum visibility (by 3M) • 3-D construction of wings via PhotoModeler
• 1 mounted at root of tail facing forward • Down-linked for fly/abort decision and recorded on ground
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29 Camera Set-up
• BENQ DC300 mini - Automate picture-taking process by timing trigger - Internal memory enables 26 Pictures to be stored at 640x480 resolution, or107 Pictures to be stored at 320x240 resolution (awaiting ground tests) - 2' to Infinity depth of field - Highest resolution/depth of field : weight
• Different regimes of flight will be photographed: - Wings deployed and in curing process - Low density regime - High dynamic pull-out - Low altitude flight
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Wing Material Cure Testing
• Goal of cure tests: to determine cure time for wings upon deployment
• Wing materials including films, fabrics, and epoxy resin were provided by ILC Dover.
• A 10”x10” mold was constructed in order to assemble composite lay-ups
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30 Wing Material Cure Testing MODTRAN 4.2: UV Intensity Results
Altitude 10 AM 11 AM
50,000 ft 27 W/m2 30 W/m2
100,000 ft 27.8 W/m2 30.7 W/m2
– MODTRAN 4.2 accounts for Lat/Long in Denver, position of sun, date/time of day, eccentricity, altitude, absorptivity of the gases, dust, and particles in the atmosphere – Reliability of software indicated by NOAA
• UV lamp for cure testing: a high density spot beam with an output of 116 W/m2 and 50 W/m2 (at 2” and 10” respectively) – The lamp will be scaled to the appropriate distance from the samples during cure test to represent the UV Intensities above
• A plexiglass pressure vessel aligns samples to model the separation between upper and lower layers of the wings
• 2-D Conduction/Convection software called FEHT was used to determine temperature profile representing heat loss upon wing deployment – Thermal Vacuum Chamber will simulate this temperature profile
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Wing Material Cure Testing
• Testing method is a cantilever beam type test, performed as follows:
– 10” X 10” samples are cured under various UV exposure times – Each sample is cut into 2” beams, clamped on one end / loaded on cantilevered end • Different strips from the same cure coupon are tested for normalization of data and repeatability assessment of the manufactured sample – Flexural bending stiffness is then obtained from deflection measurements – Fully cured samples tested first, and subsequent test strips cured for varying lengths of time – Varying calculated stiffnesses are then correlated to varying cure times to obtain a quantitative degree of cure
• Current cure test status: familiarized with composite assembly and cure test method
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31 Wing Material Cure Testing
Fully Cured Composite Sample (20m exposure)
0.02 0.018 0.016 0.014 0.012 Beam 1 0.01 Beam 2
Force (lb) Force 0.008 0.006 Beam 3 0.004 Average 0.002 y = 0.0119x - 0.0011 0 0 0.5 1 1.5 2 Deflection (in)
• Future cure test plans: corrected UV intensities representative of irradiation at 50k feet and pressurized composite samples (at 7 psig) • Ambient room temperature cure tests within 1 week • Simulated temperature-at-altitude cure tests within 2 weeks
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Wing Thermal Analysis (Conduction & Convection)
• Objective: to find surface temperature of wings as a function of time upon deployment to assess temperature profile for cure tests
• FEHT Conduction and Convection Conditions: - Wings deployed at 50k feet with most conservative assumptions: - wind speed (43 ft/s) and kinematic viscosity of air used to obtain convection coefficient through external flow Re, Nu, Pr - Initial wing temperature estimated at 90ºF (305 K) - Initial ambient temperature estimated at -94ºF (205 K) - Wing cross-section geometry modeled accurately at max thickness - Composite material modeled as glass for a conservative conduction constant, k = 0.80W/m2K - Boundary conditions - Fuselage end is adiabatic - Other three are exposed to convection
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32 Wing Thermal Analysis (Conduction & Convection) • FEHT Results:
Time to Time to 32°F 40°F (min) (min) avg 5.5 4.8 min 3.5 2.5
t=0s t=60s t=120s t=180s t=240s t=300s t=360s t=420s avg 305 298.31 292.17 286.45 281.11 276.13 271.48 267.14 max 305 306.3 305.7 303.7 300.9 297.8 294.4 291.1 min 305 290.1 282.2 275.8 270.2 265.1 260.5 256.3
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Wing Thermal Analysis (Radiation)
Material Absorp Emiss MODTRAN Total Spectral Outside skin - - Irradiation Containment layer 0.14 0.28 Glass fabric - - Altitude 10 AM 11 AM
50,000 ft G = 1082 W/m2 1199 W/m2 Epoxy - -
100,000 ft G = 1102 W/m2 1221 W/m2 Combined fabric/epoxy 0.325 0.827
Bladder - -
• Radiation Assumptions (deficient): • Absorptivity = 0.23 (avg) • Emissivity = 0.55 (avg) • Radiation Calculation Results:
4 4 2 q''(G =1082) = αG −ε surf σTs + ε skyσT∞ = −10.29W / m 4 4 2 q''(G =1221) = αG −ε surf σTs + ε skyσT∞ = 20.98W / m
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33 Major Risks
• Loss of power to any particular instrument
• Loss of communication (or data drop-out)
• Poor camera picture due to resolution, condensation on lenses, depth of field, direct sunlight, glare
• Small duration of camera data collected may not be representative of entire flight
• Wings fail to fully rigidize
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Power and Communications
Kelly Demaree Marcus Folchi Sharmila Kesavalu Andy Martin David Sadler Travis Thomas Aaron Welch Dr. William Smith, Advisor
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34 Objectives
• Provide power for all systems needing it • Provide the ability to track the glider • Provide communication to/from the glider • Provide a data-link for some data gathered to/from the glider • Minimize weight and power as much as possible
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Batteries
Rated Rated Rated Energy Energy Power Safe Cell Weight Cost Min Temp Max Temp Brand Chem. Model # Voltage Capacity Energy Density Cost Rating Discharge Type (oz) ($) (deg C) (deg C) (V) (Ah) (wh) (Wh/lb) ($/Wh) (W) Time (hr) Military BA5513 Li/? D 3.00 7.50 22.50 3.00 120.00 3.25 0.14 6.00 3.75 -55.00 70.00 (Saft) LX3457D Ultralife Li/MnO2 9V U9VL 9.00 1.20 10.80 1.20 144.00 5.75 0.53 1.08 10.00 -20.00 60.00 U3360 Ultralife Li/MnO2 D 3.00 11.00 33.00 4.13 127.85 53.70 1.63 9.00 3.67 -40.00 72.00 HCES
The military surplus batteries can dissipate 6 W per cell safely. At 25W of average power consumption, using a 6 cell arrangement with the military surplus batteries will last 5.4 hours. 10 cells (about 2 lbs) will last 9 hours.
Backup battery: Use one or more Ultralife 9V batteries, or their version of a D cell with a high power rating (9V)
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35 Vehicle Chute Block Misc. Power Sensors Chute Parachute Contro Diagram Wing Pressure l Deploy Sensor
Control Still Surfaces Camera s Main Control Flight Sensors Control Memory
Navigation GPS Video Flt. Data Camera Store
Data Video Power Link APRS Xmit Memory Sensors XCVR Xmit
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Block Diagram
Data APRS Link Video Satellite Net. Rcvr. XCVR
Tracking Internet Mission Control
Web Ground Station Interface
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36 Tracking the glider
GPS APRS
• Primary source for tracking via • Can be used as beacon if GPS datalink fails • Will also be used for some • Might suffice as a beacon to control and navigation satisfy the FAA’s requirement
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Communication/Data Transfer
• Focusing on 440 MHz band (70cm band) for data link: 445.975 MHz • Frequency for APRS and beacon: 145.6 MHz • There will be power regulation through voltage regulators and zener diodes • Capacitors will be used for filtering to ensure electromagnetic compatibility
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37 Communication/Data Transfer
• Fast scan TV is possible at 900 MHz or 1300 MHz with a separate transmitter. Extent of this is still under investigation • Slow scan TV still under investigation • Kenwood radios model THD7AG and TMD700A
- Dual band, onboard TNC, no fixed antenna, 5W transmitting power, lightweight
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Antenna
Antenna will be a omni-directional dipole or monopole. Antenna will be mounted to vertical portion of tail.
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38 Risks and Mitigation
• Power failure • Thermal issues • GPS/APRS fail • Data link failure/out of range
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Verification
• Thermal chamber testing of all parts • Pressure testing of some devices, including batteries • Compatibility test with EOSS prior to launch day • Life testing on batteries • Ground testing of all data links • Possible low altitude testing of equipment and data links
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39 Minimizing Weight and Power
• Expected totals: • Weight: 3.75 lbs (2 lbs batteries, 1.75 lbs other equipment) • Power: 10 W used by Power / Communications • BIG BLUE glider total power consumption: 16.6 W
• Final decisions on all parts will be done to optimize weight and power requirements • Power ultimately determines capabilities
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Flight Control I Alex Settles Brian King Shelby Shreve Brent Dupree Flight Control II
Scott Massa Dustin Elliott Troy Schmidt Mandy Hart
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40 OBJECTIVES
• To integrate a commercially designed autopilot system into a model glider aircraft – Learn operation of MicroPilot user interface • Gain flight experience with only tail-mounted control surfaces (elevator and rudder) • Implementation of final autopilot design into BIG BLUE aircraft
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Timeline
• Flight testing of Big White without MicroPilot system 10-12 2002 • Implement stability subroutines into MicroPilot system in Big White 12 2002 • Flight testing of Big White and Big Purple flight platforms 3/3-3/7 • Flight testing Big Red flight platform 3/7-3/14 • Flight testing of Micropilot 3/3-3/14 • Primary sensor flight testing 3/14-3/28 • Autopilot controlled flight testing 4/1-4/10 • Ground cured autopilot flight testing 4/11-4/30 • High altitude flight demonstration 5/3
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41 MicroPilot 1100
Gyros & Altim e te r Acce lero m e te rs GPS
Control System Speed Microprocessor Rx (P ito t Tube ) Receiver
Servo Motors Speed Tx Controller Rc Controller Control Surfaces
Motor & Prop
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MicroPilot 1100
• Specifications • Limitations – Multiple waypoint GPS –Maximum operating altitude of navigation 1500 feet – All sensors included for –Maximum operation velocity of airframe stabilization 150 fps – Data log capability –No telemetry transmission – Existing waypoint flexibility –No in-flight reprogramming of command buffer –50,000 byte limit on data log –No takeoff or landing autonomy
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42 MicroPilot 1100 Alternatives
• MicroPilot 2000 • Additional Advantages • Disadvantages – Allows in-flight –More than twice the cost of reprogramming of command MP1100 buffer –Same velocity and altitude – In-flight gain adjustment limitations as MP1100 – Provides autonomous take-off –Cost not justified by added and landing capability capability
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Autopilot Systems
Sensors Commercial Big Blue Minimum
Gyroscopes 3 axis 2 axis 1 axis
Accelerometers 3 axis 2 axis 0 axis
Magnetometers 3 2 0
GPS Yes Yes No
Pressure Absolute and Absolute and Differential Differential Differential
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43 Flight Path
• Release from weather balloon
• Stabilize vehicle
• Execute several full circle turns
• Continue flight back to launch location
• Circle turn about launch location
• Parachute deployment at low altitude
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Risk Protocol
•Loss of GPS signal •Loss of GPS and Magnetometers
–Triangulate position using ham –Flight control system yields constant radios bank angle to guide craft into spiral decent path –Guide flight path using magnetometers
•Abort Situations
–Loss of differential pressure sensor data
–Loss of both gyroscopes
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44 Avionics and Control
Rajiv Nandivada Alexander Maroudis Sherlton Dieterich Alan Bailey Key Kai Wong Casey Harr Kishore Mogatadakala Viswanadha Kakarlapudi Wei Lu Andrew Tan Grant Stucker David Jackson Stephen Justice Osamah Rawashdeh
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Objectives
• Design a sensor pack that can determine the attitude and flight performance of the vehicle • Design servo interfaces to allow computer control of the aircraft control surfaces • Design algorithms to stabilize the aircraft using feedback from the sensor pack • Design navigation functions that will allow the aircraft to carry out programmed flight profiles and fly to waypoints • Manage the data-link between the ground station and the vehicle
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45 Objectives (cont.)
• Provide control signals for other subsystems • Interface with sensors and log data from other subsystems • Manage the flight data store (non-volatile "black-box") • Manage the parachute control logic
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Vehicle Interconnection
Vehicle Chute Misc. Power Sensors Chute Parachute Control Wing Pressure Deploy Sensor
Control Surfaces Still Cameras Main Control Flight Control Sensors
Memory
Navigation GPS Video Flt. Data Camera Store
Data VideoX Power Link APRS mit Memory Sensors XCVR Xmit
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46 Ground Station Interconnection
Data Link APRS Net. Video XCVR Rcvr.
Tracking Internet Mission Control
Web Ground Station Interface
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Autopilot Block Diagram
Rudder Servo
Elev. Gyroscopes Servo (2)
Control Accelerometers Surfaces (2)
Flight Control Sensors Differential Pressure Sensor
Absolute Pressure Navigation GPS Sensor (2)
Magnetometers (1)
Temperature Sensors (1+)
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47 Autopilot and Control Design
• We have chosen a popular 8051 variant microcontroller made by Cygnal Integrated Products (the design will require 1-5 microcontrollers ) • We will regulate the 12V supply down to 5V and 3V for the various processors and sensors (majority of the system runs at 3V) • We have identified sensors for the design • Weight will be less than 10 oz. (285 grams) • Power consumption will be less than 1 Watt (not including the servos)
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Cygnal Family of Microcontrollers • Mixed signal designs with high speed, high resolution Analog subsystem • In-circuit programming, in-circuit emulation • Integrated IDE Keil C compiler • 11 pin devices through 100 pin devices based on 8051 core • Crossbar to make use of limited pin count • Reasonably priced evaluation boards and processors • http://www.cygnal.com
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48 Selector Guide
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Cygnal Family Architecture
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49 Cygnal Evaluation Kit
•JTAG Interface for fast in-circuit programming and in-circuit debugging
•Entire kit around ~$100 (target boards ~$50)
•Keil Software Development Tools are powerful and inexpensive
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Accelerometers
• Accelerometers will be used for the attitude of the aircraft (orientation of an aircraft's axes relative to the horizon) • We will be using the Analog Devices ADXL202E • Size: 0.2” x 0.2” x 0.08” (5 mm x 5 mm x 2 mm) • Weight : < .035 oz. (< 1g) • Power Consumption : <0.6mA @ 3V • Operating Temperature : -40 to 85 °C • -2 g to +2 g • Interface: Duty Cycle using 1 GPIO for each axis
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50 Accelerometers (cont.) +3V 8 8051 7 ADXL202E 1 X channel Duty R GPIO Cycle output set (input) 6 T2 2
5 X 3 GPIO out Yout (input) 4
Y channel Duty Cycle output
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Rate Gyros
• The sensor we chose: Murata ENC-03M • Size: 0.622” x 0.315” x 0.17” (15.8mm x 8.0mm x 4.3mm) • Weight: 0.014 oz. (0.4 g) • Power Consumption: max 3mA @ 3V • Operating temperature: -5 to 75 °C • Maximum angular velocity: ±300º/s • Interface: Voltage measured by 1 ATD pin ea.
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51 Gyro Rate Sensors (cont.)
ATD
8051 MC
ATD
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Magnetometer • Magnetometer chosen is the Vector 2X from Precision Navigation • It serves as a compass to aid navigation (accuracy 2º) • Size : 1.50" x 1.30" x 0.39” (38.1mm x 33mm x 9.9mm) • Weight: 0.3 oz (8.5g) • Supply Voltage: TTL regulated (5V±0.25V) • Power Consumption: 4mA @ 5V • Operating Temperature: -20 to 70ºC • Interface: SPI (BCD or Binary)
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52 Magnetometer - Connections
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GPS • We have selected the M12 0n-Core GPS from Motorola • Serial Communication:NMEA 0183 protocol, Software selectable baud rate • Size: 1.57” x 2.36” x 0.39” (40.0 x 60.0 x 10.0 mm) • Weight: Receiver 0.9 oz (25g), Active Antenna Module < 1.4 oz (40 g) • Power consumption: <61mA@3V (w/o antenna) • Operating Temperature: -40 C to 85ºC • Altitude: Velocity limited to < 1000 knots (515 m/s) above 60,000 ft. (18,000m) • Interface: TTL (0-3v) UART
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53 M12 – On-core receiver
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GPS Interfacing
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54 Outside Air Temperature Sensing
• The TMP100 temperature sensor by Texas Instruments will be used to determine OAT and will be mounted in the slip stream. • Size: 0.12” x 0.067” x 0.037” (3mm x 1.7mm x 0.95mm) • Weight: <0.035 oz. (<1g) • Power Consumption: 45µA@3V • Range: -55º to 125ºC,±1º accuracy, ±0.0625ºC resolution • Interface: I2C Interface 40ms conversion rate, 25 conversions per second
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TMP100
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55 Using Thermocouples
•Thermocouples may be necessary for some of the temperature measurements, if so we will use the MAX6674 thermocouple interface chip •Size: 0.197” x 0.157” x 0.069” (5mm x 4mm x 1.75mm) •Weight: < .035 oz. (< 1g) •Power Consumption: 1mA@3V •8-pin SO Package,SPI- compatible serial interface •Range: 0°C to +128 °C @ 0.125 °C resolution •Accuracy: ±2 °C for the range 0 °C to +125 °C •Cost: $3.5 – $4 per chip •Interface: SPI
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MAX6674 Thermocouple Controller
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56 Differential Pressure Sensor
• We will be using the Motorola MPX5050 differential pressure sensor to measure indicated airspeed. • Size: 0.325” x 1.177” x 1.15” • Weight: < 0.35 oz. • Power Consumption: 7mA @ 5V • Operating Temperature: -40 to 125 °C • 0 to 450 MPH (0-250 MPH with 2.8V A2D) • Interface: Analog voltage 0.2-4.7V
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Absolute Pressure Sensors • Two absolute pressure sensors will be used to measure altitude over the range the aircraft will fly • We will be using the Motorola MPX4250A for lower altitude measurements (250-20 kPa, 0 to 50,000 ft.) • Size: 0.325” x 1.177” x 1.15” (8.3mm x 30mm x 29.2mm) • Weight: < 0.35 oz. • Power Consumption: 7mA @ 5V • Operating Temperature : -40 to 125 °C • Interface: Analog voltage 0.2-4.9V
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57 Absolute Pressure Sensors (cont.) • We will be using the Motorola MPX2102 for high altitude (100-0 kPa, 0 – 200,000 ft) • Size: 0.325” x 1.177” x 1.15” (8.3mm x 30mm x 29.2mm) • Weight: < 0.35 oz. • Power Consumption: 6mA @ 10V to 16V • Operating Temperature : -40 to 125 °C • Interface: Analog voltage 0 to 40mV
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Pressure Sensor Interface 8051
A2D Input 1 MPX2102 1 GND -Vout 4 Differential 2 +Vout Vs 3 Amplifier
A2D Input 2 MPX4250A 1 Vout N/C 6 2 Gnd N/C 5 3 Vs N/C 4
MPX5050 1 Vout N/C 6 A2D Input 3 2 Gnd N/C 5 3 Vs N/C 4 10 V2 5 V1
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58 Servos
• Servos will be used to control the elevator and rudder in the aircraft • Servos vary widely in the maximum torque they can provide and in the power they consume • Servos are controlled by PWM signals. PWM commands can be generated by the microcontroller using either the timer or counter array subsystems.
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Servos (cont.) • Worst case will require high torque/high speed servos such as the Hitec HS-5645MG • Size: 1.59” x 0.77” x 1.48” • Weight: 2.12 oz. ea. (60g ea.) • Stall Torque: 10.3 kg.cm at 4.8v ; 12.1 kg.cm at 6v • Power Consumption: [email protected] or 450mA@6V under no load operation • Operating Temperature:-20 to 60ºC • Interface: PWM signals (3V to 5V)
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59 Servos (cont.) 4.8-6V
3-5V
Elevator GPIO Servo
8051 4.8-6V 3-5V
GPIO
Rudder
Servo
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Flight Data storage (EEPROM)
• We have decide upon the 512 K Microchip 24LC512 • Size: 0.373” x 0.25” x 0.155” (9.46mm x 6.35mm x 3.94mm) • Weight: 0.035 to 0.07 oz. (1-2g) • Power Consumption: 3mA@3V • Operating Temperature: -40°C to +125°C • Cascadable for up to eight devices • 5 ms max write-cycle time and about 1,000,000 erase/write cycles • Price: $ 2-3 per unit. • Speed: 100kHz, <=2.5V, 400kHz 2.5V - 5.5V • Interface: I2C
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60 EEPROM (Microchip 24LC512)
512 K (64 K x 8) I2C CMOS SERIAL EEPROM Interfacing with 8051
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Autopilot Block Diagram
Rudder Servo
Elev. Gyroscopes Servo (2)
Control Accelerometers Surfaces (2)
Flight Control Sensors Differential Pressure Sensor
Absolute Pressure Navigation GPS Sensor (2)
Magnetometers (1)
Temperature Sensors (1+)
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61 Issues
• We need to know the never exceed speed, maneuvering speed, stall speed, and best glide speed • Some sensors are very temperature sensitive and we may need to control temperature inside the aircraft • Most sensors have backups but aircraft control requires at least one gyro and airspeed measurement. The design includes two gyros but we may want to add a second differential pressure sensor • We need a way to determine the autopilot feedback gains for the low Reynolds number environment at altitude
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Issues (cont.)
• Servos may be a problem from a power standpoint • Some of the pressure sensors require 10-16V • The bandwidth of the data link is limited and may be an issue for telemetry data • Control loop rates may be high, requiring substantial processor power • The amount of non-volatile memory required will depend on data rates and sensor counts • Performance of all electronics over the temperature and pressure expected for the flight must be verified
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62 Timeline • Flight testing of Big White and Big Purple flight platforms 3/3-3/7 • Flight testing Big Red flight platform 3/7-3/14 • Flight testing of commercial autopilots (Micropilot) 3/7- 3/14 • Primary sensor testing 3/7- 3/21 • Primary sensor flight testing 3/14-3/28
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Timeline (cont.) • Primary flight control tests w/Servos 3/21-4/4 • Chamber testing of sensors, servos, and controllers 4/4-4/11 • Basic autopilot testing (holding gyro rates, airspeeds, and headings) 4/4-4/11 • Advanced autopilot testing (GPS navigation, flight profiles) 4/14-4/18 • Acceptance test in target vehicle 4/21-4/25
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63 Timeline (cont.)
• Final testing and tuning of autopilot before launch 4/25-5/3 • Launch date 5/3
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Flight Watch Web Design
Matt Field
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64 Flight Watch Web Design
Goals: • To provide a way for the members of the team who can’t make it to the launch to track the flight remotely • To allow our sponsors to track the flight • To serve as a community outreach within Lexington and abroad • To let the FAA track our flight path
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APRS
• Our flight will be tracked using a system called APRS (Automated Position Reporting System) • APRS, developed by Bob Bruninga, uses amateur radio to transmit GPS position information • Local RF networks are linked http://www.findu.com/cgi-bin/plot.cgi?call=*&geo=usa.geo&nocall=1 together through the Internet to form a single wide area network
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65 findU.com
• FindU.com, developed by Steve Dimse, maintains a database of APRS data • It provides numerous interfaces to access this data and plot it on maps • The Flight Watch web site will use live images generated by findU.com to track our flight
http://www.findu.com/cgi-bin/breadcrumb.cgi?call=n0kkz&geo=http://www.eoss.org/aprs/geokeys.txt&start=720
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Sample findU.com Track Plot
http://www.findu.com/cgi-bin/track.cgi?call=k4hg-8&geo=keys.geo&start=10000
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66 Other Plans
• Relay live images from the flight to the web (coordinated with Data Acquisition and Communications) • Display other flight data (temperature, pressure, etc.) on the web • If live data turns out to be impractical, then at the least add video capabilities after the flight
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