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?