Solar Powered Aircraft - fzt.haw-hamburg.de · Hannes Ross, IBR, EWADE, Mai 2009, Sevilla 2 Flyaroung the World with a Solar Powered Aircraft 1. Solar Power, Basics 2. Flying Power,

Hannes Ross, IBR ,EWADE, Mai 2009, Sevilla

www.solarimpulse.com 1

Solar Powered AircraftThe True All Electric Aircraft



Fly aroung the World with a Solar Powered Aircraft

1. Solar Power, Basics2. Flying Power, Basics3. Solar Powered AC History4. Technology Status5. Manned Solar Powered AC,

Solarimpulse6. Summary



0,0

2,0

4,0

6,0

8,0

10,0

1800 1850 1900 1950 2000 2050

Mill

iard

en

Today

Earth Population: More than 6 Billion in 2006



Solar Cells on Roof‘s



„Renewable“ Energy: A Requirement for Mankind

Solar PoweredSpace Craft



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, Basics2. Flying Power, Basics3. Solar Powered AC History4. Technology Status and Challenges5. Manned Solar Powered AC, SI6. 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

radi

atio

non

hor

izon

tal s

urf

ace

[W/m

²]

Solar Power Collection

Average Solar Power ~260 W/m²

Energy Storage Required:

Potential Energy,Battery



Wing Loading and Power LoadingFor Horizontal Flight

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

2*)3/2(^

CDCL

SP

SW

=

ρ

2/3^*2/3^*

2

*3^**

1**

2

*2^**

**

2

2

2

2

CLCD

SW

SP

SVCDP

CLSW

VVelocity

SVCDDDrag

VDPVelocityDragPower

=

=

=→

=→

=→=

ρ

ρρ

ρ

KKK

KKK



Power Train SchematicAnd Typical Losses/Efficiencies

MPPT~95%

BatteryManager 99,5%

Batteries 96.5%

Converter 98,5%

Motor 93%

Solar Cells, 20%

Propeller 77%

Electric Lines 99,5%

From solar energy to propeller = 89% losses!!MPPT= Maximum Power Point Tracker

Other consumers



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




First Unmanned Solar Powered ACRay Bouchers „Sunrise1“, 1974



Gossamer Condor by P. McReady



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



Unmanned Solar AircraftNASA's Environmental Research Aircraftand Sensor Technology (ERAST) Program

75m Wingspan



Alan Cocconi, So LongEl Mirage Dry Lake in California

First 48 hour flight of an UAV, 2005



26 August 2008The ZEPHYR(~30kg) flew for 82 hours 37 minutes,beating the current official world record for unmanned flight, set by Global Hawk in 2001 at 30 hours 24 minutes.



Contents




Relative MassbreakdownRelated to Maximum TOGW

Solar Powered ACneed a• Superlight structure• a very efficient

propulsion system0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

PassengerJet

Military Jet SolarPowered

Payload+FuelEquipment/SystemsPropulsionStructure



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

•Structures

• 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



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



Electrical System Schematic

Solar CellModules

MPPT+ -

MPPT+ -

MPPT+ -

Ground Connector

DC/DC Inverter

28V system

Management System

Battery

MotorDC/AC

INV.

MMS

- + Power Bus, 270 V

TemperaturProp.Lage



Solar Power GeneratorTypical Data

Solar cellSize: 125mm x 125 mm à ~ 60 cells/m² !

for a solar area of 200m² --> ~12 000 cells !Voltage: output varies with cell temperature and load ~0,6 V

Mass: 0,480 kg/m²à 96 kg /200m²

Structural Flexibility: adapt to wing deformation, no load pick-up

Solar Cell Arrangement 60 Module cordwise , 320 Cell/String = spanwise

Maximum Powerpoint Tracker (MPPT= electronic control unit):1 MPPT can control up to 4 modules à ~36 MPPT‘s for 200m²



Battery CharacteristicsTypical Data

Voltage: 4,2 V fully charged, 3.2 V fully discharged

Specific energy: ~ >200 Wh/kg

Number in Battery Pack: 290 (Max Voltage)/4,2 = 70 unitsTotal Battery Capacity for an aircraft: 86 kWh

Total Battery Mass: à 436 kg

Battery Unit Capacity, Mass and Volume: variable, àmanufacturer

Temperature: 15°C < T < 35°C, requires monitoring & conditioning

Battery pack forAntares Sailplane



Electrical Motors

• High efficiency• Low weight (higher RPMàtransmission system), low volume• Good RPM controllability• Operational between -50°C to 110° C

• Type’s– DC– Asynchron– Synchron– Transversalflow

Motor for Antares Sailplane 42 KW,Propeller diameter 2m



Structural Design

Primary materials: • Carbon Fibre Composites, • Foam, • (Transparent) plastic skin/foilStructural concepts• Tubular- / Box - Spar• Sandwich• Grid structure

• Specific wing mass ~ 2kg/m²• No statistical data available!! • Ground handling is a tricky



Helios, normal wing bending at 1g



Helios Accident

High Aspect Ratio and low wing loading result in high wing spanàelastic

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



18.08.1932: Der schweizerische Physiker Auguste Piccard (1884-1962) erreicht mit seinem Ballon »FNRS« eine Höhe von 16.940 mund dringt damit in die Stratosphäre vor. Piccard und der Physiker M. Cosyns sitzen dabei in einer kugelförmigen Druckkabine. Die Forscher führen Strahlungsmessungen durch und beweisen die Ungefährlichkeit des Aufenthaltes in größeren Höhen für Menschen in Druckkabinen - eine wichtige Erkenntnis für den Luftverkehr.



Am 23. Januar 1960 tauchte der Amerikaner mit dem Schweizer Jacques Piccard in die "Challenger-Tiefe", knapp 400 Kilometer südwestlich der Pazifik-Insel Guam. Mit knapp 11.000 Metern ist sie einer der Kandidaten für den tiefsten Punkt der Erde. Das Fahrzeug, ein Bathyscaph namens "Trieste", hatte Piccard gemeinsam mit seinem Vater Auguste im Jahre 1953 entwickelt und 1959 an die US-Navyverkauft. Als die Navy ein Jahr später zum Tiefen-Rekord ausholte, übertrug sie Don Walsh das Kommando.



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

March 1999



Solar Impulse ProgramInitiated 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 nightCycle à 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



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 available power 5. Fly at minimum night altitude

0 24

Mission Profile



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)

Rel

ativ

e V

alu

es

Power RequiredSolar Power Available

Flying at low altituderequires less energy



Typical Configuration

• Conventional configuration • Main weight in wing (partially span loaded aircraft)• Ultra low wing loading (~ 8 kg/m2)• Design optimized for : low power loading, high

aerodynamic and propulsion efficiencies• Carbon epoxy HM & HT ultra light primary structures



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 (K

Wh

), 1

0 A

LT

(km

)

Alt*10 [km]

SOLENAC [Kwh]

ENBATAC [Kwh]

ENTOTAC [Kwh]

ENWASTEAC [Kwh]

Collected Solar Energy

RequiredFlight Energy

Altitude

Battery energy

Mission Parameter (2)

Daytime (h)



1200

1400

1600

1800

2000

2200

100 150 200 250 300

Wing Area

Wei

ght (

kg),

Increasing AROptimum design: Correct • wing size= Solar power, energy• wing shape: Span/AR• battery size, battery mass

No Design Solutions

Unbalanced solutions:Too much • Wing area=Solar energy Wrong •AR/span• Battery capacity/weight

W/S=10kg/m² 9 8

7

6

Design Space



Optimum Design Solutions

0,5

1

1,5

2

2,5

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

Wing Area

Wei

ght,

Spa

n, A

R

AR(relative)

Span (Relative)

Weight (Relative)



Take-off Weight and Wingloading

0

500

1000

1500

2000

0 50 100 150 200 250

Wing Area, m²

Tak

e-o

ff W

eig

ht,

kg

Man-Powered

Solar Powered, Manned

Solar Powered, Unmanned

Battery Powered, Manned

Sailplane, Manned

10 8 6

W/S=4kg/m²

40 20

HeliosETA

Antares

Solar Impulse

Icare

15

2



SI Prototype Aircraft HB-SIA

© Solar Impulse/EPFL Claudio Leonardi






Test Fixture for 10m Wingbox

Source. SOLAR iMPULSE



Example: Horizontal StabilizerTest article of 2.6m*1.7m




Example: Horizontal StabilizerTest article of 2.6m*1.7m

Current 3.5kg




Cockpit Structure:

CFC sandwichand foam shell

© Solar Impulse/Stéphane Gros





Gongola Structure and Engine

© Solar Impulse/Stéphane Gros







© Solar Impulse/Stéphane Gros© Solar Impulse/Stéphane Gros



















Cockpit













Where shall we fly? (21 June)

0,80

0,85

0,90

0,95

1,00

1,05

0 20 40 60 80 100

Latitude, degRel

ativ

e ac

umul

ated

ene

rgy,

Dub

ai=1






Solar Impulse, Cockpit Mock-up, Record Aircraft

© Solar Impulse



Current design: Record Aircraft

© Solar Impulse



Program Schedule

It is a long term project:

2003 Feasibility study at the EPFL de Lausanne in2003 Announcement of challenge on 28 November2004-2006 Concept Development 2007-2009 Design and manufacturing of a prototype, 2009, June Unveiling of Prototype, initial test flights 2010 36 hour record flight2009-2011 Design and Construction of the final airplane 2012 Missions of several days, crossing of the Atlantic

and tentative tour of the world completing in five stages



Conclusions

The development of a manned solar powered aircraft capable of staying aloft for more than 24 hours is still a big challenge: It requires

• an aircraft with very large physical dimensions, (area and wing span)

• Ultra light structural design with high stiffness

• Solar cells with very high efficiency (> 20%)

• Batteries with very high specific energy capacity (>200 Wh/kg)

• Very light and efficient electrical engine

• Minimum equipment mass and electrical consumption



With Solar Power around the world:




The Core Team

© Solar Impulse

With Solar Power around the world:

We want to do it!



André Borschberg Bertrand Piccard Luiggino Torrigiani

Program Founders

© Solar Impulse



Main Partners

Official Partners

Official Supporters

Official Suppliers

Scientific and aeronautical partnerships



E N D

Documents

Solar Powered Aircraft - fzt.haw-hamburg.de · Hannes Ross, IBR, EWADE, Mai 2009, Sevilla 2 Flyaroung the World with a Solar Powered Aircraft 1. Solar Power, Basics 2. Flying Power,