Solar Impulse Project

"Solar Impulse" is a long-range solar plane project currently under study at the EPFL. The project is promoted by Bertrand Piccard, and aims at completely solar-powered circumnavigation.

The aircraft is intended to be a one-seater, capable of taking off autonomously, and to remain airborne for days. Once the efficiency of the batteries makes it possible to reduce the weight, a two-seater is planned to make circumnavigation possible.

Project

Proposed timeline

* 2003: Feasibility study at the École Polytechnique Fédérale de Lausanne.
* 2004-2005: Development of the concept.
* 2006: Simulation of long-haul flights.
* 2006-2007: prototype.
* 2008-2009: prototype test flights
* 2009-2010: construction of the final plane
* 2011: several-day-missions, crossing the Atlantic and trials circumnavigating the globe in five stages

Take-off is proposed for May 2011, for a flight around the world near the equator, but essentially in the northern hemisphere. Five stops are planned to change pilots. Each leg will last three to four days, limited by the physiology of the human pilot.

Aerodynamics

The wingspan of "Solar Impulse" will be 80 metres, slightly wider than the wingspan of an Airbus A380, in order to minimise drag and offer a maximum surface for solar cells. Such light wing loading (8 kg/m²) creates greater sensitivity to turbulence. The ultra-light structure must use customised carbon fibres.

Structure

While traditional sandwich composites have an area density in the order of 10 kg/m², those developed for "Solar Impulse" should weigh in the order of 0.5 kg/m². These materials could also have functionality integrated, such as integrity sensors, active control of the form, etc.

A layer of ultra-thin solar cells will be integrated to the wings. These cells are designed to be flexible enough to withstand deformations and vibrations.

Energy

Photovoltaic cells will generate electricity during the day, which will serve both to propel the plane and to recharge the batteries to allow flight at night. Energy accumulated during the day will be stored in lithium batteries in the wings, the density of which must be close to 200 Wh/kg, in spite of temperatures ranging from +80 C to –60 C.

Propulsion

The average power provided to the engines will be on the order of 12 hp, comparable to that of the "Wright Flyer".

Cockpit

The cockpit will provide pressurisation, oxygen and various environmental support to the pilot to allow a cruise altitude of 12,000 metres.

Partners

The project is partially financed by private companies such as Solvay, Omega, Deutsche Bank and Altran. The EPFL, the European Space Agency (ESA) and Dassault provide technical expertise.

External links

* [http://www.solarimpulse.com Solar Impulse Web site]
* [http://bertrandpiccard.com Bertrand Piccard's Web site]
* [http://www.robotpig.net/aerospace/en_solar_impulse.php article about solar impulse]
* [http://www.greenermachine.com/index.php?pOption=post&pPostId=21 Article on the SolarImpulse project]
* [http://www.solarimpulsevirtualflight.com/ Virtual Flight 2008 - 25-hour flight]

ee also

aircontent
related=

similar aircraft=
* Helios Prototype
sequence=

lists=

see also=
* [http://en.wikiversity.org/wiki/School:Aviation Wikiversity School of Aviation]