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Hand-Launched Electric Fuel Cell UAVPT2020 High Endurance Aircraft

Critical Design Review | Senior Team 5

December 6th, 2010 | 10:45am

Team 5 Member Introduction

Agenda• Overview of Purpose & Mission• Design Requirements• Compliance Assessment• Approach • Program Plan• Design Walkthrough w/ Individual Reports• Appropriate Standards & FARs• Constraints & Risk Assessment Matrix• Failure Modes and Effects Analysis (FMEA)• Environmental, Societal, and Global Impacts

Purpose Statement“Produce a detailed design for a hand launched, fixed

wing, electric fuel cell powered Unmanned Aerial Vehicle (UAV) engineered for maximum endurance”

Lockheed Martin © Desert Hawk UAVAeroVironment© Raven B System UAVPhoto courtesy of www.lockheedmartin.comPhoto courtesy of www.avinc.com

Why Develop this UAV?• Electric fuel cell provides large possible performance

gains in small, hand launched UAV field• Hand launching enables quick and easy use in dynamic

situations (warfare, law enforcement)• Multi-mission versatility provides wide variety of uses• Provides a real world design task to learn introductory

design practices by trial & error methods• Enter a new niche in the UAV field

Simulation Video

AeroVironment© Raven RQ11 Simulation Videohttp://www.avinc.com/

Design Requirements • Hand launchable by human of average physical strength• Uses a real world, market available electric fuel cell• Payload of 200 in3 volume, 5 pounds, and 20 watts• 3 UAV units can be transported in a small pick up truck• Capable of skid landings• 25 to 35 knots speed range• 14,000 feet MSL service ceiling• 1,000 feet AGL operating altitude• Lockheed Martin Corporation©

Lockheed Martin © Desert Hawk UAVPhoto courtesy of www.lockheedmartin.com

Baseline Deliverables

B Level Team Grade

Mechanical Design and 3D Render

Risk Matrix, and Risk Mitigation

Plan

Aerodynamic Analysis

Requirement Derivation Project Plan

(Gantt Chart)Performance

Analysis

Requirements Verification

Matrix

Supplementary DeliverablesCompleted Extra

Deliverables

Production Feasibility

Range & Endurance

Calculations

Cruise Speed Calculations

Interior Structural

DesignCost Analysis

Control Surfaces

CAD Modeling

Disassembly Methods

Future Possibilities

Longitudinal Aerodynamic

Stability

Component CAD

Modeling

Interior Structure

CAD Modeling

Design Outline3.7 Meters (12.4 Feet)

Wingspan

1.9 Meters (6.3 Feet)Tip-To-Tail

17 Inch DiameterPropeller

9.1 Kilograms (20.1Pounds)

Total Mass

Compliance Assessment• Hand Launchable• Electric Fuel Cell Usage• Payload Specifications• Transportability • Skid Landing Capable• Speed Range• 14,000 Feet MSL Service Ceiling• 1,000 Feet AGL Operating Altitude

Compliance Assessment• Hand Launchable

– Challenges of Weight, Wingspan, and Takeoff Velocity– Built a Prototype UAV: Same Mass & Dimensions – Tested by Performing 3 Test Throws

Compliance Assessment

Hand-Launchable Test Compilation VideoTeam 5 Recorded 11/22/2010

Compliance Assessment• Powered by Electric Fuel Cell

– Choose Horizon Energy Systems Aeropak• Payload Requirements

– UAV has 200 in3 volume, 5 pounds, and 20 watts payload split into two compartments

Compliance Assessment

– Easily Transport 3 UAVs in the Truck Bed

– Chevy S10 Truck Modeling (72” x 50”)

• Transportable by Small Truck

Compliance Assessment• Capable of Skid Landing

– Designed to Sustain Impact– However, Computational Analysis &

Real Testing was Not Completed– Time and Expertise

Compliance Assessment• 25 to 35 Knots Speed Range

– Meets min/max cruise speed– Stall speed never exceeds 18 knots– Maximum dash speed is 65 knots, cruise at 35 kts

has 5 hours endurance• 14,000 feet MSL service ceiling

– Operating altitude up to 14,000 feet– Speed requirements met at 14,000 feet

• 1,000 feet AGL operating altitude

Assessment Conclusions• Hand Launchable• Electric Fuel Cell Usage• Payload Specifications• Transportability • Skid Landing Capable• Speed Range• 14,000 Feet MSL Service Ceiling• 1,000 Feet AGL Operating Altitude

Approach• Identify Driving Requirements• Initial Sizing as Team• Breakdown into Components• Integrated Design• Identified Problems • Rebuilt from Basic Sizing to Solve Problems• Performed Computational and Physical Tests• Finalized Design • Calculated Capabilities

Program Plan

Start Date: September 8th, 2010

Requirements Defined: September 24th, 2010

General Sizing: October 8th, 2010

Preliminary Design Review: October 29th, 2010

Critical Design Review: December 6th, 2010 (Today)

Requirements Re-Evaluation: November 12th, 2010

Nick Kranowski Task Report

Component Integration

Appropriate Standards

Design Reviews

Presentation

Sponsor & Faculty Liaison

Requirement Derivations

& Matrix

Systems Engineering

Design Walkthrough

How Does a Fuel Cell Work?• Water from the

reservoir is separated• Hydrogen enters Anode

and breaks down• O2 enters Cathode and

breaks down• Hydrogen Protons

migrate through PEM• Electrons pass around

PEM

Video courtesy of www.howstuffworks.com

Fuel Cell Selection• Horizon Energy Systems Aeropak

– Available Power: 240 Watts (Sea Level)

– Available Continuous Current: 10 Amps

– Output Voltage Range: 20-32 Volts

– Mass (w/ Fuel Cartridge): 2 Kilograms

– Deliver Up to 900 Watt-hours Photo courtesy of www.sae.org

Fuel Cell Advantages• Batteries to Fuel Cells

– Lithium ion battery: 150Wh/kg– Horizon Aeropak: 450Wh/kg– 3x Improvement

• Benefits of Fuel Cells– Have endurance of 3x that

of comparable batteries– Easy refueling (no recharge)

Battery Type Energy Density (kJ/kg)Lead – Acid 79.2

Lithium Polymer 602Sodium – Sulfur 792

Mg hydride with Ni catalyst 8,280Gasoline 47,500Hydrogen 120,000 – 142,000

Altitude Restriction

Photo courtesy of www.horizonfuelcell.com

Addition of Battery Pack • Initial estimates showed insufficient speed/altitude• Battery pack needed to extend flight envelope• Takeoff and climb assistance• Choice: Thunder Power Pro

Lite MS Series TP-40004S2PL• Endurance = 4000mAh• Constant Voltage = 14.8V• Max Burst Current = 100A• Weight = 338g Photo courtesy of www.rctoys.com

Electronic Speed Control• Castle Creations Phoenix 60 ESC• Max Current = 60A• Weight = 58g• Programmable with auto-shutoff• For brushless motors

Photo courtesy of www.rctoys.com

• Fuel Cell Selection– Horizon Energy Systems Aeropak– Zero greenhouse gas emissions– Greater endurance than batteries– Longer range

• Further work– Research fuel cells with higher energy densities– Increase altitude operation of fuel cell

Individual Conclusions & Recommendations

Cameron Japuntich Task Report

Plane Storage

Modeling

Motor & Motor

Controller Assistance

Fuel Cell Limitation Research

Propeller Selection

AssistanceGantt Chart

Creation

Fuel Cell Selection

Wing Design

Wing Design

Wing Design

Chart courtesy of Aircraft Design (Raymer)

Wing Design

Wing Design• Using metal CNC die, carbon wing shell can

be vacuum bag molded• Use of mold/casting methods eliminates

need for foam core• Vacuum bagging produces lightest weight

and highest quality • Carbon wing spar with honeycomb internal

structure offers high weight to strength

Individual Conclusions & Recommendations• Conclusions

– Low Reynolds flow is a growing field– Structural analysis of composites is difficult

• Recommendations– Full FEA analysis of wing structure– Thorough verification of aerodynamic characteristics

using more advanced CFD– Talk to composites expert about best options

Garrison Hoe Task Report

Cost Analysis

Assistance

Analysis of Wing

Capabilities

Wing Structure & Materials

Risk Matrix Mitigation

Plan

Failure Modes and

Effects Analysis

Wing Airfoil Selection

Tail Structure

Tail Design

Airfoil Selection Tail•

Tail Control Surfaces• Rudder and elevator are usually 90% span

starting at fuselage with 25-50% of chord• Taper ratios are same as tail’s

• UAV tail is sufficient for stability• Matches specifications based on main wing

dependence• More tail loading analysis to minimize weight• Tools like ANSYS could be used• Further research into composites• Review NACA 0015 airfoil (increases stalling angle)

Individual Conclusions & Recommendations

Fuselage Design Factors

PerformanceSkid Landing

Payload SupportTruck TransportHand Launched

Structures

Materials Profile

Dimensions

Bottom-Up Design

Component Selection & Sizing

Component Layout

Profile and Cross Sections

Lofting and Structures

Stability and Performance

Requirements

Materials

• Major Components• Fuel Cell• Avionics Payload• Motor

• Minor Components• Motor Controller• Servos• Battery

Avionics Camera• Cloud Cap Technologies

Tase LT• SWAP: (12.1 x 9.71 x 8.99)

cm, 1 lb and 10 W• Sony FCB-IX11A EO

camera with 10x optical zoom

Photo courtesy of www.cloudcaptech.com

Component LayoutBattery

Motor

Front Payload

Fuel CellRear Payload w/

Camera

Fuselage Exterior

Structures and Materials• NACA inlets• Carbon fiber-Kevlar

hybrid Skid Plate• Lexan Camera

Protection• Carbon fiber balsa core

bulkheads and firewall• 2 layers of twill weave

carbon fiber body• Mass=670 g, L=0.985 m Photo courtesy of www.dragonplate.com

Tail Boom• Length=87 cm,

Diameter = 3.81 cm • Mass = 200 g• 1 mm thick carbon

fiber epoxy• Carbon fiber-Kevlar

Hybrid skid plate• Detachable from

fuselage

• Structural Analysis Required– Impact Analysis, FEA

• Wind Tunnel Testing on scale model– Verify XFLR5 data

• Highly desirable for military operations– Long range, transportable, hand launched

Individual Conclusions & Recommendations

Greg Hoepfner Task Report

CAD Modeling Internals

CAD Modeling Fuselage

CAD Modeling Tail

Boom

CAD Modeling

OML & Final UAV

XFLR5 Full UAV Analysis

Fuselage Design

Airfoils Selection• Wing root uses S4022 airfoil• Wing tip uses Wortmann FX 60-126 airfoil• S4022 is design for low Reynolds number and

high lift• Wortmann FX 60-126’s geometry is design to

achieve aerodynamic twist for stability• Use XFLR5 to analyze the wing

Wing Aerodynamics• Based on the wing analysis, take-off speed at

sea-level is:

• The initial estimated weight is 7 kg• This is only based on the wing’s aerodynamic

analysis.

m/s 89.822.12/1

max

=

=

LTO CS

WVρ

-5 0 5 10 15 20-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

angle of attack, α (degree)

Lift

coef

ficie

nt, C

L

CL vs α

Main WingAircraft

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.80

0.05

0.1

0.15

Lift Coefficient, CL

Dra

g co

effic

ient

, CD

Drag Polar

Main WingAircraft

Aircraft Aerodynamics• Static Margin

– 13% of the Chord

• Center of Gravity– 55.2 cm from the nose– Change in the fuel has a negligible effect on the

center of gravity

13.0=−= cgnn hhK

Longitudinal Aerodynamic Stability Derivatives

Derivatives• Axial force due to velocity• Axial force due to “incidence”• Axial force due to pitch rate• Axial force due to downwash lag

• Normal force due to velocity• Normal force due to “incidence”• Normal force due to pitch rate

Value1019.0−=uX

4534.0=WX0498.0−=qX0158.0−=•

WX

732.1−=uZ425.4−=WZ

2150.2−=qZ

Longitudinal Aerodynamic Stability Derivatives

Derivatives• Normal force due to downwash lag• Pitching moment due to velocity• Pitching moment due to “incidence”• Pitching moment due to pitch rate• Pitching moment due to downwash lag

Value7026.0−=•

WZ

0≈uM7484.0−=WM

1838.2−=•W

M8846.6−=qM

• Use XFLR5 to analyze the aircraft with elevator, rudder, and ailerons on

• Perform lateral stability analysis• Perform second iteration of longitudinal

stability analysis• Match XFLR5 Model with CAD model• Perform Stability Augmentation analysis

Individual Conclusions & Recommendations

Chandra Tjhai Task Report

XFLR5 Profile

Calculations

Hand Launchability

AnalysisAerodynamic Calculations

Center of Mass

Identification

Longitudinal Stability

Calculations

Real World UAV

Research

Components/Avionics

Components/Avionics

02468

1012141618

0 50 100 150 200

Torq

ue R

equi

red

(kg-

cm)

Control Surface Span (cm)

Torque Required

2cm Chord4cm Chord6cm Chord8cm Chord10cm Chord12cm Chord

RudderAileron Elevator

Flap

Components/Avionics

• MKS DS450• Weight: 9.5g• Torque: 3.1 kg-cm

• BMS-306MAX• Weight: 7.1g• Torque: 1.6 kg-cm

• BMS-820DMG• Weight: 45g• Torque: 9.2 kg-cm

Ailerons & Elevator Rudder Flaps

Image courtesy hobbyking.com Image courtesy modellbauen.ch Image courtesy romaniamall.ro

Motor and Propeller

Motor• Lightweight and efficient• Effective at various power

levels• Brushless• No gearbox necessary• Small enough for

fuselage• Sufficient documentation

Propeller• Folding propeller for skid-

landing• Large enough to provide

thrust required• Maximum efficiency at

upper speed limit• Matched diameter/pitch

with motor RPM

Motor and Propeller• Motocalc used to

model efficiency• Entire range of

documented motors iterated

• Propellers from 10”x5” up to 24”x12”

• Tested at fuel cell rated power output: 200W

Motor and Propeller

Motor• Neu 1915-2Y• Kv = 360 RPM/V• Weight = 397g• Max rated power =

1800WPropeller• Aero-Naut CAMcarbon

folding propeller• 17” diameter by 11” pitch

Image courtesy fastelectrics.com

Image courtesy hacker-motor-shop.com

Motor and Propeller• 63% total propulsive

efficiency at 35kts• 32N static thrust at

600W: 4m/s2 takeoff acceleration

• Sufficient power for launch speeds down to 7 m/s

Performance Analysis

Without Battery• Max

Altitude = 11500 ft

• Max Velocity = 37 kts

Performance Analysis

With Battery• Altitude and

velocity no concern

Performance Analysis

• Max ROC = 9.6 kts

• Climb 1000ft in 62s

0

2

4

6

8

10

12

0 2000 4000 6000 8000 10000 12000 14000 16000

Rat

e of

Clim

b (k

ts)

Altitude (ft)

Maximum Rate of Climb

Max ROC

Max ROC with Battery

Performance Analysis

y = 989.03x-1.07

0

2

4

6

8

10

12

14

16

0 50 100 150 200 250

Endu

ranc

e (h

rs)

Power Output (Watts)

Endurance vs. Power Output

Performance Analysis

0

2

4

6

8

10

12

0 2000 4000 6000 8000 10000 12000 14000 16000

Endu

ranc

e (h

rs)

Altitude (ft)

EnduranceTakeoff Velocity

Takeoff Velocity With Battery

25 kts Cruise

25 kts Cruise With Battery

35 kts Cruise

35 kts Cruise With Battery

• Max Endurance: 10.3 hrs

Performance Analysis

0

50

100

150

200

250

0 2000 4000 6000 8000 10000 12000 14000 16000

Ran

ge (n

mi)

Altitude (ft)

Range25 kts Cruise

25 kts Cruise With Battery

35 kts Cruise

35 kts Cruise with Battery

Maximum Range

Maximum Range with Battery

• Max Range: 235nmi

• Achieved at 11000ft, 30.7 kts

• Fuel cell technology needs more improvement for aerospace applications

• Documentation of fuel cells on the market very lacking• Fuel cell difficult to model in performance-estimating

applications• A lighter payload and/or no hand-launch restriction would

allow greater performance• ANSYS data could provide better drag characteristics

Individual Conclusions & Recommendations

Erik Eid Task Report

Speed Controller Selection

Motor & Propeller Selection

Performance Analysis

Range & Endurance Calculation

Altitude & Speed

Analysis

Avionics Analysis

Risk AssessmentRisk Probability Impact

Fuel Cell Operation at High Altitude Medium High

Light-weight Composite Wing & Fuselage Design High Low

Meeting Hand Launch Requirement Low High

Meeting Speed/Altitude Requirements Medium Medium

Aircraft Aerodynamics and Static Margin Medium Medium

Prop Strike on Skid Landing Low Low

High Lift Devices (Flaps) High Low

Easy Assembly on Ground Low Medium

FMEAMODES OF FAILURE PROBABILITY SEVERITY SOLUTION

Wing structural failure Low HighFEA and flight testing aswell as frequent field inspections

Control surface detachment Low Medium Kevlar hinges and flight

testing

Fuel cell malfunction Low HighEnsure that fuel cell is operated within manufacturer limits

Aircraft loses control Extremely Low HighControl surfaces have programed default positions that spiral airplane

Engine failure Extremely Low Medium Emergency landing required

Prop strike on hand launch Low Medium

Prop is located in the front of aircraft away from launcher

FMEAMODES OF FAILURE PROBABILITY SEVERITY SOLUTIONBird strike Extremely Low High No solutionLithium Polymer battery explosion Low High Follow Li-Po handling

procedure

High winds Medium Medium Set thresh-hold for operable wind conditions

Icing Extremely Low HighDefine environmental constraints or install anti-icing for wings or pito-probe

Hard impact on skid landing Low Medium

Kevlar and impact foam implemented for shock absorption

Damage during ground transport Low Medium

Transportation case is designed to take abuse while retaining internal integrity

Federal Aviation Regulations• Two means of operating UAS in NAS outside of “restricted” airspace

– Special Airworthiness Certificate – Experimental Category– Certificate of Waiver or Authorization (COA)

• FAA created the Unmanned Aircraft Program Office (UAPO) and the Air Traffic Organization (ATO) UAS office to help integrate UASs into the NAS

• FAA is working with members of the UAS community to define operating and certification requirements that are critical for allowing UAS access to the NAS

• The FAA has tasked RTCA to advise on technical issues of developing UAS standards targeted to be complete before 2015. Two questions that need answering;– How will UASs handle communication, command, and control?– How will UASs “sense and avoid” other aircraft?

Source: www.faa.gov, Published Sept. 20, 2010

Production Feasibility• Wing and tail are the hardest parts to build• Creativity skills needed, especially for homebuilt• Material selections important

– Heavy fuel cell– Met hand launch requirement

• Not hard to build from industrial point of view

Cost AnalysisCOMPONENT DESCRIPTION COSTWings Total Cost $250

5.7oz 3k 2x2 Twill Carbon Fiber $48.06Honeycomb Dragon Plate $154.86Balsa $20

Fuselage Total Cost $2005.7oz 3k 2x2 Twill Carbon Fiber $38.80Carbon/Kevlar Twill $6.181/8” Lexan $3.45Balsa Core Dragon Plate $134.80

Tail Boom Total Cost $130Carbon Fiber Tube $120Carbon/Kevlar Twill $1.33

Cost AnalysisCOMPONENT DESCRIPTION COSTElectronic Components

Total Cost $671

Servos $227.95Brushless Motor $2354000mah 4S Li-Po Battery

$189.99

Prop and Spinner $18Tail Total Cost $47

Carbon Shell $21EPS Foam Core $6Carbon Tube $20

Aircraft Materials Cost(Fuel Cell Not Included) $1300

Environmental Impacts• Environmentally Friendly

– No Greenhouse gas emission– Requires no recharge– Byproducts are water and heat– Step away from dependence on

harmful batteries• Concerns

– Aided by lithium battery use (disposal is hazardous to environment)

– Need to create a recycling procedure

Photo courtesy of www.constructiondigital.com

Societal Impacts• UAV potential search operations • Lead to more extensive research

in fuel cell technology• Displace human (solely) pilots • Invasion of privacy regarding

citizen spying• Air traffic control issues in

domestic flight patterns• Possible bomb usage at further

distances, lessening moral conflictPhoto courtesy of

www.acecombatskies.com

Global/Military Impacts• Can provide battlefield

intelligence to save lives • Creates new role for quick-

deploying, high endurance surveillance

• Benefits allies on the United States of America in areas of high secrecy and security

• Large hydrogen consumption (more efficient hydrogen isolation methods needed)

• Provide exploration of dangerous territory

Photo courtesy of New York Times Newspaper

Hand-Launched Electric Fuel Cell UAVPT2020 High Endurance Aircraft

Critical Design Review | Senior Team 5

December 6th, 2010 | 10:45am

APPENDICES

Additional Documentation

NACA 64-012A

NACA 64-012A

NEW Recommendations from Steve of Tail Airfoil Selection

NACA 0015 SPECS RECOMMENDATION FROM STEVE

Mass Balance

Mass Balance

Aircraft Aerodynamics• Static Margin

−+=

αε

dd

aaVhh Tn 11

180)(180

cos5.0

180 cos5.0

180 cos5.0

180 cos5.085

5 22

22

22

2

22

2

2

2

π

π

π

π

π

παε ∑

=

++

+

+

++

+

+

=fi zx

x

zfi

zfixx

zfix

fi

Ara

dd

1822.0=−= cgnn hhK

Longitudinal Aerodynamic Stability Derivatives

• Aerodynamics of aircraft

At trim condition (C_M = 0):

/rad372.4=a /rad784.41 =a m 4086.0=c m 27.1=Tl

/rad3172.0=αε

dd

45.0=TV /rad784.41 =a

m/s 14V 053.0C 866.0 7.4 0D ===°= LCα

0 0

/rad1076.0 s/m 0003175.0 /rad4125.0

≈∂∂

≈∂∂

=∂

∂−=

∂∂

=∂∂

VC

VC

CVCC

ML

T

DDD T

αα

Longitudinal Aerodynamic Stability Derivatives

VSVVCVCX D

Du ∂∂

+∂∂

−−=τ

ρ 0

0

21

12

α∂∂

−= DLW

CCX

T

DTq

TC

VXα∂

∂−=

αε

ddXX q

W=•

Aircraft Aerodynamics• Use XFLR5 to analyze the aircraft aerodynamics

Longitudinal Aerodynamic Stability Derivatives

VCVM M

u ∂∂

= 0

αddCM M

W =

claVM T

Tq 1−=

αε

ddMM q

W=•

VCVCZ L

Lu ∂∂

−−= 02

α∂∂

−−= LDW

CCZ

1aVZ Tq −=

αε

ddZZ q

W=•

Real World Large Scale UAVs

ASM Swift Flight Hand Launched Flight Videohttp://www.youtube.com/

Component Placement

Truck Transportation Methods

Wing XFLR5 Analysis

Wing Polars from XFLR5

First Order Airplane Polars From XFLR5