Solar Impulse Flies Across America 0


If there is anything cooler than a solar-powered airplane that can fly at night, we sure haven’t seen it.  The plane is called Solar Impulse (technically HB-SIA) and it is making its way across the country right now!  In fact, if you live in Phoenix, you could go see it today or Tuesday (and yes, we are jealous) – but the free tickets to see it are all sold out!

The plane is making its way across the United States, originating in San Francisco, with scheduled stops in Phoenix, Dallas, St. Louis, DC and New York City.  The information learned during the flight will inform the design and construction of a second plane (HB-SIB) that is intended to fly around the world in 2015.

Here are some specs of the Solar Impulse:

Wingspan: 208′ Weight: 3,500 lbs
Length: 71′ Height: 20′
Motors: 4 (each 10hp) Solar cells: 11,628

The plane has a take-off speed of 27 mph, an average flying speed of 43 mph and a maximum cruising altitude of 27,900′!

Indeed, the plane has already garnered Five World Records including:

  • Absolute height: 30,300′
  • Altitude gain: 28,690′
  • Duration: 26 hours, 10 minutes, 19 seconds
  • Free distance along a course: 695.5 miles
  • Straight distance over pre-declared waypoints: 683 miles

But how, you may ask, does a solar powered plane fly at night?  Clearly it is not fast enough to chase the sun, so what happens when the sun goes down?  It is all about energy management – both electrical and potential.  During daylight, as the nearly 12,000 solar cells are producing power, the plan climbs toward its service ceiling.  As it goes higher, the solar power system becomes more efficient due to both the drop in temperature and the thinning of the atmosphere.  Thus, the plane is able to store energy in two forms: electro-chemical (in the batteries) and potential in the altitude attained.

When the sunlight fades, the plane begins a very gradual descent, aided by its massive wingspan – equivalent to an Airbus A340 jetliner – that allows it to glide long distances forward for every foot of descent.  Finally it levels off and flies at a very slow cruising speed powered by the solar power now stored in its batteries until it once again meets the sun and can begin its ascent once again.  In theory, the plane could do this perpetually – not so the poor pilot!

Speaking of the pilots, one of them, Bertrand Piccard, has quite the lineage as a pioneer.  His father, Jacques Piccard was aboard the Bathyscaphe Trieste (designed by his father, Auguste) when it descended to the ocean floor in the Mariana Trench – some 35,814′ deep – in 1960!

Original Article on Founder’s Blog

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