Around the World with a Solar Powered Aircraft1. …...Hannes Ross, IBR, 20.01.2011 DGLR, RAeS, VDI,...

Hannes Ross, IBR , 20.01.2011

DGLR, RAeS, VDI, @HAW Hamburgwww.solarimpulse.com

Around the World with a Solar Powered Aircraft1. Solar Power, Basics

2. Flying Power, Basics

3. Solar Powered AC History

4. Technology Status

5. Solar Impulse Program,

6. Summary



Primary Energy CollectionParameters

Earth Rotational Axis

Sun light

Lattitude, Time of the year, Time of the day, Altitude (Clouds, humidity), Cell TemperatureCell Orientation

1000

800

600

400

200

4 8 12 16 20 24Day Time (hrs)

Sun Radiation (W/m²), Oberpfaffenhofen

Summer

Winter

Source: B.KeidelDissertation



Energy (W)Collected

Solar Energy Collection

Solar Cell Area (m²)

Theoretical Limit of SC efficiency:~28 %, monocristaline Silizium~29 % Gallium Arsenid

~20% for high techapplication

~14 % for ground basedsystems (e.g.solar roof)

Energy collected is proportional to solar cell area!

Solar Cell Cost



Contents

1. Solar Power, Basics



4. Technology Status and Challenges

5. Manned Solar Powered AC, SI

6. Summary



Available Solar Power

Solar constant 1300W/m² extraterrestrialAt flight altitudes approx. 1000W/m² noon peak

0

100

200

300

400

500

600

700

800

900

1000

0 3 6 9 12 15 18 21 24

h sunrise to sunset

rad

iati

on

on

ho

rizo

nta

l su

rface

[W/m

²]

Solar Power Collection

Average Solar Power ~260 W/m²

Energy Storage Required:

Potential Energy, Battery



Power Train SchematicAnd Typical Losses/Efficiencies

MPPT~95%

BatteryManager 99,5%

Batteries 96.5%

Converter 98,5%

Motor 93%

Solar Cells, 20%

Propeller 85%

Electric Lines 99,5%

From solar energy to propeller ~ 85% losses!!

MPPT= Maximum Power Point Tracker

Other consumers



Wing Loading and Power LoadingFor Horizontal Flight

)3/2(^*)3/1(^

2*)3/2(^

CD

CL

S

P

S

W

=

ρ

2/3^*2/3^*

2

*3^**

1**

2

*2^**

**

2

2

2

2

CL

CD

S

W

S

P

SVCDP

CLS

WVVelocity

SVCDDDrag

VDPVelocityDragPower

=

=

=→

=→

=→=

ρ

ρ

ρ

ρ



L/D=37

35

33

31

29

6,00

7,00

8,00

9,00

0,02 0,025 0,03 0,035

Aspect Ratio

Wingloading, kg/m²

Solar Power, KW/m²

Design Point

Max. Solarpoweravailable

Design Space



Contents






6. Summary



Solar Powered ACsince 1974

Ray Boucher‘s„Sunrise1“, 1974

Gossamer Condor, P. McReady, 1979

Alan Cocconi, 200548 hours

Qinetic, Zephyr1 week, 2010



Solar Challenger 1981McReady

262 km, 5 hrs,2.5 KW

Solair 1 1983Günter Rochelt

> 5 hrs, 2.2 KW

Icare 2 1996

Voit-Nitschmann350 km, 3.5 KW

Sunseeker 1990

E. Raymond400 km

Unmanned Helios

2001Aerovironment30’000 m, 21 KW

1980 1990 2000

Solar Aircraft History



Contents






6. Summary



Propulsion

• high specific power solar array >20%

• high specific energy batteries > 200 Wh/kg

• high efficiency electric motors

• high efficiency propeller

• thermal control systems for batteries, engines

• lightweight composite structures

• acceptable aero-elastic characteristics

Systems with Low Power Consumption

• FCS, ECS, Communication, Navigation,

Technological ChallengesFor manned ac with flight time >24 hr’s

Structures



Stand 2008

Source: ZAE Bayern

2004 2006 2008

22

20

Solar Cell Efficiency



Lithium-Ion Battery Development

Wh/kg

Wh/lUS$/Wh

Source: www.battery university.com



Helios, normal wing bending at 1g



Helios Accident

High Aspect Ratio and low wing loading result in high wing span��elastic

structure



Contents

1. Solar Power, Basics2. Flying Power, Basics3. Solar Powered AC History4. Technology Status and

Challenges5. Manned Solar Powered AC:

The Solar Impulse Project6. Summary



Bertrand Piccard decided to launch into a new futuristic enterprise: to fly round the world in a solar-powered aeroplane

March 1999



Solar Impulse Program

Initiated 2001 by Bertrand Piccard and André BorschbergObjective:Develop a manned solar powered aircraftwhich can fly around the world with solarpower only

Feasibility Study 2002-2003

Approach:

Develop a „Demonstrator“ aircraft to show a 24hr energy neutral day and night Cycle �� HB-SIA

Develop the „Record“ aircraft, capable of crossing Atlantic, Pacific in 4 to 5 day`s and fly around the world in 5 to 6 legs



Relative Flight Power Required and Solarpower generated=f(Altitude)

1

1,1

1,2

1,3

1,4

1,5

1,6

1,7

1,8

1,9

0 2 4 6 8 10 12

Altitude (km)

Re

lati

ve

Va

lue

s

Power Required

Solar Power Available

Flying at low altituderequires less energy



12

3

4

5Min night altitude

Max cruise altitudeAltitude

1. Fly at minimum night altitude2. Climb3. Cruise at at max altitude,if power is available4. Descent at idle power 5. Fly at minimum night altitude

0 24

Mission Profile



Design/Scaling Program

Requirements

Assumptions

Baseline aircraft

Design data

Performance

Requirementsmet?

DesignExperienceCreativity

no

Iteration

Yes



0 4 8 12 16 20 24

Daytime

Alt*5 [km]

SOLP [Kw]

PBAT [Kw]

PTOT [Kw]

Altitude

Solarpower

Power required

Battery Power

Daytime

Mission Parameter (1)



Refined Baseline, W/S=8.05, AR=18.36

0

50

100

150

200

250

300

0 4 8 12 16 20 24

Daytime (h)

En

erg

y (

KW

h),

10

AL

T(k

m)

Alt*10 [km]

SOLENAC [Kwh]

ENBATAC [Kwh]

ENTOTAC [Kwh]

ENWASTEAC [Kwh]

Collected Solar Energy

RequiredFlight Energy

Altitude

Battery energy

Mission Parameter (2)

Daytime (h)



Optimum Design Solutions

0,5

1

1,5

2

2,5

0,6 0,8 1 1,2 1,4

Wing Area

We

igh

t, S

pa

n, A

R

AR(relative)

Span (relative)

Weight (relative)


DGLR, RAeS, VDI, @HAW Hamburg1

Size Comparison

© Solar Impulse/EPFL Claudio Leonardi



Operational Performance

100 200 300 400 500 600 700 800

Velocity, km/hr

70

60

50

40

30

20

10 Military Aircraft

L/D

Sailplanes

UltralLight Sailplanes

Commercial Airplanes

Sport/Utiliy AC

Solar Powered Airplanes



Design Characteristics

100 200 300 400 500 600 700

1,3

1,2

1,1

1,0

0,9

0,8

0,7

0,6

0,5

0,4

0,3

0,2

0,1

MilitaryAircraft

Commercial AC

Motorgliders

Solar ac = 0,03

Wingloading,(kp/m²)

Thrust/Weight



Load Limit Tests



Cockpit Structure: CFC sandwich and foam shell

© Solar Impulse/Stéphane Gros



Low Cost „Windtunnel“ Testing

Engine

MPPT´s

Gear

Cooling Fan



Initial Ground Vibration Test, 3



Wing Assembly 3



Solar Cell Attachment



Instrument Panel



Finally: Lift-off, 7.April 2010



In The Air



First Landing



Demonstration of a 24 HourNeutral Energy Cycle

26 hour flight7th/8th July 2010



Swiss Flights to Genf, Zürich



Program Schedule

It is a long term project: 2003 Feasibility study at the EPFL de Lausanne 2003 Announcement of challenge on 28 November2004-2006 Concept the final Development 2007-2009 Design and Manufacturing of the prototype A/C, test

of the airplane, 2009 June Unveiling of Prototype, initial test flights 2010 April First flight in Payerne2010 7/8 July 26 hour record flight, from Payerne2011----------------------------------------------------------------- time now2011-2012 Design, construction, start ground tests2013 Flight test, Missions of several days 2014 Crossing continents, Atlantic and tour of the world

five/six legs, each about 5 days long



Because of the Sponsors: A low cost program!

Main Partners

Official Partners

Official Supporters

Official Suppliers

Scientific and aeronautical partnerships



Design of the Record AircraftTo fly around

The World



Principle Design Window

• For a given payload the minimum weight is achieved with the highest ARLimited by the maximum tolerable wingspan!!

• The more stringent the design mission is, the more will the design windowShift towards higher weight and larger wing area!!

Weight

Wing Area

Wing Loading

Aspect Ratio

Wingspan

Payload

Max Wing Chord

Design Point



Solarimpulse: ONE TEAM



END

Around the World with a Solar Powered Aircraft1. …...Hannes Ross, IBR, 20.01.2011 DGLR, RAeS, VDI,...

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