Sun-powered airplane flies at record altitude!

Sun-powered airplane flies at record altitude!

Jumbo jet

Some airplanes can transport hundreds of people.


Some airplanes can travel several times faster than sound.

Aerobatic monoplane.

Some airplanes can do dipsy-doodles and loop-de-loops.

Then there is Helios . . .
  • The Helios Prototype airplane weighs less than most cars and carries no people.

  • Flying at low altitudes, it is quite slow. You can ride your bicycle almost as fast!

  • And forget loop-de-loops! It takes a minute to climb the height of a 30 story building. (Most elevators climb faster!)

But the Helios Prototype airplane can do some very useful things no other airplane can do.

Helios can fly higher than any other airplane! And it uses only the Sun's energy for fuel! Helios in flight

Helios Prototype flying wing on its first test flight using solar power over the Hawaiian Islands.

On August 13, 2001, remote-control pilots on the ground used a computer to fly the Helios Prototype to an altitude of 96,863 feet. That's over 18 miles straight up! Before the Helios Prototype, the highest recorded flight of any aircraft was about 85,000 feet. This was done in 1976 by the SR-71 spy plane, the fastest jet in the world. Only rockets and rocket-powered airplanes have gone higher.

The air we breathe on Earth's surface is almost 100 times thicker than the air up where the Helios Prototype flew. Earth's atmosphere at this altitude is about as thin as the atmosphere on Mars. This altitude above Earth is so close to space that the sky is almost black, stars shine in the daytime, and the horizon looks curved.

Helios takes off on its record-setting flight.

Helios takes off from Kauai, Hawaii, August 13, 2001, on its record-setting flight.

How did Helios do it? Airplane wings must have air under them to work. What is so special about Helios' wings that they can work with so little air?

First, Helios' wings—or rather wing, since it is really just one flying wing—is 247 feet long, about a classroom width longer than a Boeing 747. But Helios is very lightweight, so this huge wing doesn't have to lift very much. How can this plane be so light? Because it is made of very lightweight materials, doesn't carry any people or fuel.

Instead of jet fuel, Helios has about 62,000 solar cells across the wing. The solar cells collect energy from the Sun and convert it to electricity, which runs the 14 small motors, which turn the 14 propellers. The propellers are specially designed to pull the aircraft aloft even in the very thin air that's 18 miles high.

Technician installs solar cells on Helios.
Helios pod contains fuel cells and landing gear.

The five pods beneath the wing contain computers, electronic operating systems, and the landing gear (made from mountain bike and scooter wheels!)

page published on May 5, 2011
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