The prototype will be called the HB-SIA.  It will fly for 36 hours straight on sunlight alone.  The final Solar Impulse will fly around the world.

As was mentioned in a previous article, the Solar Impulse project is rolling out in stages.  Several years have been devoted to designing various prototypes and researching the best materials and manufacturing processes for producing the solar planes.

Previous designs included solar planes with the engines and propellers on the rear assembly.  Another had two propellers on the front wing with the pilot cabin suspended beneath the wing.  The current design includes four propellers on the front wing that is 61 meters or 200 feet long.

Composite materials were used to make the plane as light as possible.  The plane is only 1,500 kilograms or 3,307 pounds.  The size of the wing and the light weight of the plane have posed unique challenges:

• constructing a structure with this wingspan and such a low weight;
• finding the balance between stability and maneuverable, in other words how to make an airplane of this size and with such a low wing load pilotable?

The project has employed 50 scientists from six countries and an additional 100 outside advisors to develop and test a number of new solutions for both the individual parts of the plane and the plane as a whole.  The areas requiring new approaches have been the “conception, aerodynamics, energy efficiency, structure, composite materials and manufacturing procedures” necessary to produce the parts and connect them up to form the plane.

Another issue that has had to be addressed is the storage of energy so that the plane is not forced to land after sundown as other solar planes have had to do.  Although the wingspan is covered in flexible solar cells, the cells only produce enough energy to light a light bulb.  The solar cells are having to power four engines and necessary electronics within the plane.

The size and weight of the batteries needed to power the plane have limited the plane to one passenger/pilot.  As batteries become more efficient and lighter, a second person can be added to the cockpit.

Since the ultimate goal of this first plane is to fly it for 36 hours straight (day, night,day), being able add a second person lesson fatigue on the pilot.  The test flight is scheduled for sometime this year.  An announcement is due Friday March 26th which may give the dates of the upcoming test flight.

This Solar Impulse is continuing on course.  Following the progress of this remarkable project promises to be exciting.  New techniques, technologies and materials are being developed that may soon change the way we think of air travel.

Related:

Entry was posted on Monday, March 23rd, 2009 at 11:47 pm under Green Technology, Science and technology.

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