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02/25/031
Final Design PresentationLow-cost Expendable UAV Project
22 April 2003
02/25/032
Team Members
Atalla Buretta...…......
Ryan Fowler...………
Matt Germroth...…….
Brian Hayes………….
Timothy Miller……….
Evan Neblett…………
Matt Statzer………….
Materials
Propulsion
Weights, Materials
Structures
Aerodynamics, Stability & Control
Configuration Design
Leader, Systems, Mission analysis
02/25/033
The Lemming Concept
Premise:• Provide a low-cost, expendable reconnaissance platform
• Alternative to more expensive existing UAV systems
• Incorporate aerial launch capability
• Designed for the US Navy
Rationale:
• UAV will be used for high risk missions
• Current UAVs have high loss rates
• Aerial launch allows greater service range & extended timeon station
• Not returning to base provides greater time over target
02/25/034
Request for Proposal (RFP)
To create a “cheap” UAV with the followingcharacteristics:
• Launch or drop via air vehicle
• Carry 50 pound payload
• Fly for 5 hours on a circuit (pre-determinedor directed)
• Crash
02/25/035
Design Team Requirements
• Navy aircraft Launch capability (primary orsecondary)
• Cruise altitude of 5,000 feet
• Minimum ceiling of 10,000 feet
• Speed range of 65 -140 knots
• 30-minute positioning time (launch to station)
• 5-hour loiter time
• 200 fpm ROC at 5,000 feet
02/25/036
Project Drivers
• Cost – (UAV must be expendable)
• Aerial Launch Capability
• Endurance Requirements
• Payload Requirements
02/25/037
UAV Concepts
Delta Wing
02/25/038
UAV Concepts
Folding Wing
02/25/039
UAV Concepts
Scissor Wing
02/25/0310
Selection of Preferred Concept
5.244.214.217.29Power Required (hp)
0.06190.04980.04980.0861Cd at Loiter
5.7476Manufacturing Costs
189187187193Weight (lbs)
AverageScissorFoldingDeltaFOMs
ScissorFoldingDeltaFOMs
11.50814.15516.338Total
0.8040.8041.392(3) Power Required (hp)
0.8040.8041.392(2) Cd at Loiter
0.7061.2351.059(5) Manufacturing Costs
0.9890.9891.021(4) Weight (lbs)
Normalized Selection Matrix
Detailed analysis of the 3 concepts yielded the following data
Conclusion: Scissor wing concept is preferred design
02/25/0311
Deployment
Parachute Assisted Drop Launch
Aircraft Ejection
Nose Down Attitude
Chute ReleaseFlight Surface Deployment
Self-sustained Flight
Pullout Region
Controlled Descent Region
Chute Stabilization Region
02/25/0312
Deployment
Boom Storage
Boom Extension
UAV Release
Freefall Region
Flight SurfaceDeployment
Flight Entrance Region
Self-sustained Flight
Boom Launch
02/25/0313
Deployment
Tow Line Launch
UAV Release
Descent Region
Self-sustained Flight
02/25/0314
Final 3-view
02/25/0315
Final Inboard Dimensions
02/25/0316
Final Inboard Profile
02/25/0317
Full Configuration
Structure
Flight Control
Payload
Electrical Power Communication
Propulsion
Fuel
Wing Pivot
02/25/0318
Aerodynamics
Mission:
• Airfoil Design and Selection
• Wing Optimization
• Drag / Climb estimation
02/25/0319
Aerodynamics
Airfoil:
• Desired Characteristics• Flat Bottom• ClCR
≥ 0.8• Low Cd at ClCR
• Team designed Airfoil• Xfoil MDES used to shape pressure distribution
• Compared Drag Polars• Xfoil OPER viscous polar accumulation used (Re = 8.8e5,
M = 0.1231)
• Considered Structural Acceptability
02/25/0320
Aerodynamics
Airfoil Drag Comparison:
02/25/0321
Aerodynamics
Airfoil Profile Comparison:
02/25/0322
Aerodynamics
Airfoil Selection Conclusion:
• Midnight• CLL/Dmax
= 0.889
• CLmax = 1.58
• Highest L/D = 155.4
• Best structural characteristics
02/25/0323
Aerodynamics
Wing Optimization:• CLL/Dmax
= 0.889; V = 135 fps
• Sreq. = W / (__V2CL) = 11.27ft2
• Sactual = b * c = 10ft * 14in = 11.67ft2
• Conclusion• Wing size kept same, to accommodate weight
growth during design
02/25/0324
Aerodynamics
Trimmed CUAV Lift Estimation:• Used Midnight Airfoil Polar to produce Cl for
both wing and tail
•
• Clcuav = Clwing + Cltail
˜˜˜˜
¯
ˆ
ÁÁÁÁ
Ë
Ê
˙̊˘
ÍÎÈ
⋅⋅
⋅⋅+=
cSlS
e tt
ch
Cl C C Mwblcuav
02/25/0325
Aerodynamics
Trimmed CUAV Drag Estimation:• Program “Friction” used to find Cdo of
Airframe (wing not included)• Cdoairframe
= 0.0156
• Used Midnight Airfoil Polar to produce Cdoand Cl for both wing and tail
• Cd = Cdoairframe + Cdoairfoil
+ KCl2
02/25/0326
Aerodynamics
Trimmed CUAV Polars:
02/25/0327
Stability and Control
Mission:
• Size Surfaces
• Calculate Aileron Hinge Moments
• Validate Tornado Code
• Verify Stability of Aircraft
02/25/0328
Stability and Control
Surface Sizing:
• Tail Surfaces sized in Preliminary• bactual = 2.21ft• C = 0.5ft
• Aileron Sizing using Raymer’s traditionalaileron vs percent chord
• caileron = 25%• baileron = 2ft (per aileron)
02/25/0329
Stability and Control
Hinge Moment Calculations:• Used Xfoil OPER menu, and FMOM command
• Maximum Speed and S.L. used for analysis
6.7001-4.39730.3326Bottom
6.70011.73760.2375Top
Y-Force (lb)X-Force (lb)Hinge Moment(ft-lb)
02/25/0330
Stability and Control
Tornado Verification:
• Used 2D viscous lift curve and pitch moment ofairfoil and Raymer 3D conversion
• Enter wing dimension and estimated camber lineslope of Midnight airfoil into Tornado
• Analysis• Central Difference Analysis used
• V = 45.156 m/s = 135 fps
02/25/0331
Stability and Control
Tornado Verification:
02/25/0332
Stability and Control
Tornado Validation:
0.03354.43Xfoil Results
4.64%8.47%Error
0.03504.80Tornado Results
Cm_CL_
Conclusion:• Tornado provides good approximation of stability
parameters
• Only Use Tornado for all derivatives
02/25/0333
Stability and Control
Tornado Verification:
Conclusion:• Tornado provides good approximation of stability
parameters
• Aircraft is statically stable, and stable w.r.t. controldeflections
0.2168Cn_r0.0398Cl_r
23.31%Static Margin
-0.0193Cn_a0.3145Cl_a
-2.7082Cm_e Control
Deflection
0.0130Cn_-0.0349Cl_-1.4376Cm_5.1404CL_Static
Lateral-DirectionalLongitudinal
02/25/0334
Performance
Performance was not defined in RFP
Team Defined Performance Parameters:
•Cruise altitude of 5,000 feet
•Minimum ceiling of 10,000 feet
•Speed range of 65 -140 knots
•30-minute positioning time (launch to station)
•5-hour loiter time
•200 fpm ROC at 5,000 feet
•100 fpm ROC at 10,000 feet
The CUAV easily exceeds all performance requirements
02/25/0335
Rate of Climb
Maximum rate of climb occurs at Vmp
˙˙˚
˘
ÍÍÎ
È=
CVDo
mp
k
S
W
3
2
r
W
DV
W
pbhpROC -=
h550
Altitude Max Rate of Climb Sea Level 2211 fpm 5,000 ft 1684 fpm
10,000 ft 1277 fpm
02/25/0336
Flight Envelope
For stall boundary: Clmax = 1.57 SClWV r5.0maxmin =
For Vmax boundary: Pa = Pr SVSV
WkCP dor2
2
2 5.05.0
rr ˜
˜¯
ˆÁÁË
ʘ¯ˆ
ÁËÊ+=
02/25/0337
Loiter Performance
Altitude Min Power Vel Drag Power Req'd Est. Fuel Cons. Endurance Range
Sea Level 111 fps 9.05 lbs 1.83 Hp 0.28 gal/hr 11.7 hr 880 mile5,000 ft 120 fps 9.09 lbs 1.98 Hp 0.37 gal/hr 8.6 hr 705 mile
10,000 ft 129 fps 9.029 lbs 2.12 Hp 0.48 gal/hr 6.7 hr 590 mile
0 100 200 300 400 500 600 700 800 900 10000
5
10
15Mission Profile for Cheap UAV
Distance, miles
Altiitude, 1000 ft
Sea Level5k Feet 10k Feet
02/25/0338
Engine Selection
Yes
No
No
Yes
No
ElectricStarter
$742.50962Honda GX270
QAE2
CostPower(hp)
Weight(lbs.)
Engine
$1100.0014.815Radne Raket 120
Aero ES
$799.997.56.2Fuji BT-86 Twin
$1069.9576.5Saito FA-450R3-D
$495.991055Tecumseh Power
Sport
02/25/0339
Propeller Sizing
Raymer’s Method
Assume: Activity Factor = 100 (typical for light-aircraft)
Blade design CL = 0.5
Extract propeller efficiency _p from figure 13.12 in Raymer
using equations: J = V/nd
cP = (550 bhp)/(_n3D5)
Other parameters and coefficients:
T = P_p/V
cT = T/_n2D4
cS = V(_/Pn2)1/5
02/25/0340
Altitude Power Adjustments
Power = PowerSL _ (_/_0 – (1 – _/_0)/7.55)
11.067000
10.678000
10.299000
13.172000
12.733000
12.304000
11.875000
11.466000
9.9110000
13.621000
14.80Sea Level
Adjusted Power (hp)Height (ft)
02/25/0341
Propeller Sizing
0.155250.051.14930.830.12610.782675.002.3
0.196550.051.20480.830.17950.880466.672.3
0.231945.221.27090.750.26791.006258.332.3
0.178748.241.14930.800.15740.818275.002.2
0.206444.021.20480.730.22420.920566.672.2
0.232737.991.27090.630.33461.051958.332.2
0.170047.031.10190.780.14480.771483.332.1
0.209947.031.14930.780.19870.857175.002.1
0.221439.191.20480.650.28290.964366.672.1
0.213528.941.27090.480.42221.102058.332.1
0.198745.221.10190.750.18480.810083.332.0
0.222441.001.14930.680.25360.900075.002.0
0.219431.961.20480.530.36101.012566.672.0
ThrustCoef.
Thrust(lbs)
Speed-PowerCoef.
PropEff.
PowerCoef.
Advance RatioRotation Speed
(rev/s)Diameter
(ft)
02/25/0342
Propeller Selection
• To avoid losing thrust at high speeds or RPMs, the helical tipspeed of the propeller should not get too close to the speed ofsound
Mtip = (V2 + ("nD)2)1/2/a
• At sea level, the calculated tip Mach is 0.4675, well below thespeed of sound.
• Materials: Metal, Carbon Fiber, Glass Fiber, Plastic, Wood
• Wood is the ideal material for our design.
• Zinger Propellers: 25 – 8 wood propeller costing $31.39.
02/25/0343
Engine Installation
• Mount engine upside-down. 5.1" _ 6.1" _ 0.25" Flat plate
to mount to firewall, 1.5"from top of fuselage.
• Connect fuel feed tocarburetor inlet.
• Connect throttle servo tothrottle shaft.
• Run exhaust to outside offuselage.
• Extension for engine shaft.
02/25/0344
• COMPOSITES
Bi-directional Kevlar
• ALUMINIUM
6061T6
Materials
02/25/0345
Skin material is Bi-directional Kevlar
• Good resistance to corrosion and fatigue
• Elimination of part interface
• High damping characteristics
• Low coeff of Thermal Expansion
Materials
02/25/0346
• Stress analysis using FEPC suggests reinforcementfor composite frame
• Failure at 90 degree joints may occur
Materials
02/25/0347
Aluminum 6061T6 Airframe
• Abundant and Low Cost
• Versatile
• Good formability
• Resistance to corrosion
• Ductile
Materials
02/25/0348
Material Designation
•Complete skin constructionof Composites
•Aluminum beams forreinforcement
•Fuselage and wings 0.03”
Materials
02/25/0349
Structures
02/25/0350
Structures Overview
• Wing loading– Shearing force– Bending moment
• V-n diagram– Maneuver loading– Gust conditions
• Spar designs– Shearing stress– Compressive stress– Deflection
• Aileron integration– Rear wing spar
attachment
• Tail integration– Offset bearing
system
02/25/0351
Wing loading
• Max shear force
– Level flight: 84.5 lbs
– 3g turn: 277.5 lbs
• Max bending moment
– Level flight: 174.8 ft-lbs
– 3g turn: 584.3 ft-lbs
02/25/0352
V-n Diagram
• Max structural loading 3
• Min structural loading -1.2
• Gust conditions– 66 ft/sec – stall
– 50 ft/sec – cruise
– 25 ft/sec – max velocity
02/25/0353
0 50 100 150 200 250-2
-1
0
1
2
3
4
5
Velocity (ft/sec)
V-n Diagram
Load Factor
V-n Diagram
02/25/0354
Wing Spar Design
• Designed to withstand 3g maneuver• Constructed from 6061T6 aluminum
– Yield strength of 35,000 psi in compression– Yield strength of 20,000 psi in shear
• Designed with 2 C - beams– Height of 1.54 in– Width of 0.6 in– Thickness of 0.1 in– Combined weight of 6.03 lbs– Tip deflection of 0.024 in
02/25/0355
0 2 4 6 8 10 12 14
-4
-2
0
2
4
6Spar Location
inches
inches
Spar Design
02/25/0356
Tail Spar Design
• Designed for 3g turn requirement: 67 lbs• Constructed from 6061T6 aluminum
– Yield strength of 35,000 psi in compression– Yield strength of 20,000 psi in shear
• Designed with C – beam at quarter chord– Height of 0.51 in– Width of 0.40 in– Thickness of 0.10 in– Weight of 0.27 lbs each– Tip deflection of 0.50 in
02/25/0357
Tail Spar Design
1 2 3 4 5 6
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
Spar Location
inches
inches
02/25/0358
Aileron Integration
02/25/0359
Tail Integration
02/25/0360
UAV Systems
Systems to be incorporated into UAV:
Navigation
Autopilot
Control
Communication
Electrical
Deployment
02/25/0361
Navigation and Autopilot Systems
Micropilot MP1000SYS• Micropilot MP1000SYS autopilot
• Originally designed for model airplanes
• Combines navigation and stability functions
• Integrated GPS and GPS antenna
• Designed to interface with standard RC servos
• Operates with RC transmitter or other data link
www.uavflight.com
Micropilot MP1000SYS SpecificationsGPS Accuracy ± 25 ftAltitude Accuracy ± 5 ftSpeed Limit 255 fpsAltitude Limit 25,000 ftDimensions 6" x 3.2" x 1.5“ Weight 0.33 lbs Antenna Length 48 inCurrent Draw 0.30 Amps @ 8 V Unit Cost $1,500
02/25/0362
Control System
_ Scale RC Servo
www.towerhobbies.com
• _ Scale Radio Control Model Airplane Servos
• Inexpensive, readily available, variety of choices
• Off-the-shelf integration with autopilot system
• Number and type of servos determined by hinge
moment calculations
1/4 Scale RC Servo SpecificationsDimensions 2.33" x 1.13" x 1.96"Torque 0.66 ft-lb -- 1.52 ft-lbAvg Current 97 mA -- 495 mAUnit Cost $27.99 -- $94.99
02/25/0363
Communication System
• In 1991 the DOD made the Tactical Common Data Link (TCDL)
the standard for military imaging and signals intelligence
• UAV was initially designed to use a TCDL
• Use of standard link would facilitate use of existing control stations
• Cost of TCDL is prohibitively expensive
TCDL from L3 Comm.
www.l-3.com
L-3 Communications TCDL SpecificationsRange 120 nmData Rate up to 45 MbpsDimensions 3" x 6.75" x 10"
3" x 12" x 10"Current Draw 5.89 Amps at 28 VUnit Cost 200,000 +
02/25/0364
Communication System
• CUAV will use data link built by AACOM communication systems.
• Range will be 50 miles
• Cost will be 7.5 % of TCDL cost
Range 50 miles Range 50 milesVoltage Input 28 V DC Voltage Input 28 V DCCurrent Draw 6.0 Amps Current Draw 0.20 AmpsDimensions 7" x 4.5" x 2.34" Dimensions 3" x 4" x 1.95"Weight 4.375 lbs Weight 1.31 lbsPower Output 20 WattAntennaTotal Unit Cost $15,000
AACOM AT6420 TransmitterData Link Specifications
AACOM 3000 Receiver
20" Omni-directional colinear array
02/25/0365
Electrical System
• 2 Choices for the electrical system: (generator, batteries)• Use of go-kart engine makes incorporation of generator infeasible
UAV Battery SelectionType Manufacturer Voltage Capacity Weight Dimensions CostLithium-Ion Ultra-Life 28 V 11 Ah 2.9 lb 5"x4.4"x2.45" $125Zinc - Air Electric Fuel 28 V 56 Ah 5.9 lb 12.2"x7.3"x2.4" $290Zinc - Air Electric Fuel 28 V 30 Ah 3.1 lb 12.2"x3.7"x2.7" $210
Electric Fuel Zinc-Air BA-8180/U
www.electricfuel.com
UAV Electrical RequirementsSystem Amps
Autopilot 0.30Servos (times 5) 0.50Reciever 0.20Transmitter 6.00Payload 10.00Miscellaneous 1.00Total 20.00
20 Amps x 5.5 hrs = 110 Ah
02/25/0366
Deployment System
UAV will be designed for 3 deployment options:
• Parachute Deploy
–Design of chute packaging, opening, and release systems
–Sizing of parachute
• Boom Deploy
–Design of boom and related systems
–Integration of boom attachment points into UAV design
• Tow-line
–Placement of tow-line attachment point
–Design of tow-line release mechanism
02/25/0367
Cost Analysis
Summary of Fly-Away Cost
• Engineering Costs
• Airframe Costs
• Assembly Costs
• Systems Costs
02/25/0368
Cost Analysis
Engineering Cost
• 7 member team
• 3 months concept evaluation
• 3 months detailed design
• 3 months of flight test evaluation & redesign
• Total cost = $ 300,000
• Cost per unit for 200 units = $ 1,500
02/25/0369
Airframe Cost
Study of composite kit-planes indicated thatairframe materials could be acquired for $3,000.
The group allowed $ 2,000 for airframe assembly
Total airframe cost = $ 5,000
02/25/0370
Assembly Costs
Assembly Includes:
• Joining airframe components
• Mounting and integration of UAV systems
• Final testing and quality assurance
32 man-hours at $20 per hour
Assembly Cost = $ 640
02/25/0371
Systems Cost
System Cost per UnitData Link $15,000Autopilot / Navigation $2,000Servos $ 70 x 6Batteries $580Total $18,000
Systems Cost
02/25/0372
Cost Summary
Product Engineering $1,500Airframe $5,000Systems $18,000Assembly / Testing $640Total Cost $25,140
UAV Cost Summary per Unit
Total production estimated at $ 25,140
With a profit margin, units could be soldfor less than $ 30,000
02/25/0373
Weights and CG
12
4
3
5
6
CG?
= pt. load
02/25/0374
Weights and CG
• Moment summation• S Mcg = 0;
• S Mcg = 0 = S [weighti*(localcgi-cg)]
• Features of MATLAB code• Amount of fuel (input function)
• Reads data file with over 80 specifications, explanation
• Individual weights and cg’s displayed
• Weight of skin (Kevlar), airframe (Al), and UAV displayed
• UAV CG displayed
• Ixx, Iyy displayed
• Accepts airfoil geometry
02/25/0375
Weights and CG
• Key Contributing Factors
• Skin thickness = 0.06”, Bi-directional Kevlar
• Aluminum tail boom
• Full fuel tank of 15 lb
• Payload of 50 lb
• Forward engine of 15 lb
• Most internal components behind spring
02/25/0376
Weights
• Results• Skin (Kevlar) weight = 10.61 lb
• Airframe (Aluminum) weight = 36.07 lb
• Total UAV weight = 159.39 lb
• Ixx = 216129 in4; Iyy = 759934 in4
Sample
Output
02/25/0377
CG
• Results• For full fuel and payload, cg is 0.57” in front of shaft
• Acceptable cg is from 17.9 % chord to 49.4 % chord
SPRING
LIMIT
LIMIT
02/25/0378
Conclusions
• CUAV design meets or exceeds all RFP requirements
• Maximum Payload
• Endurance
• Autonomous Operation
• Expendability
• Cost
• Lowest of all UAVs of similar performance
02/25/0379
Questions?