The Swiss solar-powered plane, Solar Impulse HB-SIA, completed its first international flight Friday morning, leaving the Payerne military airfield in Switzerland at 8:40 am local time, and landing in Zaventem airport Brussels at 9:30pm Friday evening. The Solar Impulse crossed Switzerland, Luxembourg and France in its 630 kilometer (391.4 mile) journey.
The plane completed the journey powered entirely by energy generated from the 11,628 solar cells on its wings and horizontal stabilizer. By charging the solar cells in the day, the Solar Impulse was able to use the charged cells to fly into the night.
After landing, CEO, co-founder and flight pilot André Borschberg stated, “It’s unbelievably exciting to land here in Brussels, at the heart of Europe, after flying across France and Luxembourg. And to fly without fuel, noise or pollution, making practically no negative impact, is a great source of satisfaction.”
Built on a carbon-fiber “honeycomb” skeleton, the Solar Impulse’s upper wings are covered in a solar cell-embedded skin. Its underside is covered with flexible, lightweight film. Two pods are fixed under each wing, with each pod consisting of a motor with a maximum power of 10 HP, a polymer lithium battery, and a management system.
Flying at an average altitude of 6,000 feet, the total flight time was 12 hours and 59 minutes. The long flight time was due both to the plane’s low speeds – up to 50 kilometers (approximately 31 miles) per hour – and restrictions imposed by the Zaventem air traffic control. The volume of planes landing at Zaventem airport resulted in the Solar Impulse being granted an off-peak landing slot, at 9:00pm local time.
Brussels Airport Company CEO Arnaud Feist discussed the relevance of the flight for the airline industry.
“This airplane, the first to function without fossil fuel and without emitting CO2, symbolizes the great efforts the aeronautical industry is making to develop new technologies for energy saving and increased use of renewable energies,” he stated.
The Solar Impulse weighs approximately 1.7 tons, with a wingspan a little larger than a Boeing 777 at 64 meters. Its cockpit currently seats one person. Following its successful maiden voyage in July of 2010, the solar plane has subsequently completed flights across Switzerland, in addition to a successful night flight.
The primary challenge of the international flight was navigating the busy European airspace. Due to its slow speeds, the Solar Impulse is difficult to pick-up on radar, and is slow to maneuver. Designating a flight plan that avoided larger, faster planes was a priority.
“Usually, the separation distance between aircraft is 300 meters vertically and 8 kilometers when flying at the same height. In the case of Solar Impulse, our margin of safety is much greater” Niklaus Gerber, one of the Solar Impulse team’s air traffic controllers, stated. “There are aircraft that are travelling at between 400 and 900 kilometers per hour. So the other aircraft are the ones that have to make adjustments to avoid it…An aircraft that passes above it needs to be at least 900 meters higher, due to the turbulence it creates”.
After having completed its maiden international flight, the Solar Impulse HB-SIA will be displayed in Belgium and France. Between May 23rd and 29th, it will be on show to the European institutions in Brussels. It will afterwards fly to the Paris International Air show, where it will again be displayed as a “special guest” from the 20th to the 26th of June.
Solar Impulse was founded by André Borschberg and Bertrand Piccard in Switzerland, with the goal of developing solar flight technologies. Both are pilots, with Piccard completing the first non-stop balloon flight circumventing the globe, and Borschberg trained as an engineer and fighter pilot.
Photo credit: Matth1 commons/c/cc/Flea_Hop_HB-SIA_-_Solar_Impulse.jpg