Solar Impulse - Wind Tunnel Tests

"This was proof that the project is really making progress." - Tests in the wind tunnel The engines are running, the propellers rotating. The atmosphere in the Solar Impulse hangar is electric: today is the day the engines are being tested in the wind tunnel. "When you've worked this long on technical drawings and static parts it's an amazing feeling to see those parts in motion," was Bertrand Piccard's commentary on the tests. During the record-breaking Solar Impulse round-the-world flight planned for 2011 the four 10 bhp engines will be powered exclusively by the sun. Consequently the twin blade propellers have to be extremely efficient to keep the plane in the air. The current Solar Impulse Insights video clip shows the wind tunnel tests on the 3.5 metre long propellers.