Solar Impulse 2 begins its final flight of world tour, heads to Abu dhabi

New Delhi: A crazy-looking, experimental, fuel-free plane, Solar Impulse 2 with a mission to circumnavigate the world has finally started the final leg of its historic journey and took off from Cairo on Sunday for Abu Dhabi. The solar powered aircraft will take 48 hours to reach Abu Dhabi- the place it began the circumnavigation in March 2015.

"We thought it was going to be an easy flight because it's always good weather between Egypt and Abu Dhabi across Saudi. But actually, it's extremely difficult to find a good strategy," Piccard told BBC News before take off late Saturday night.

Piccard added that the warmer, thinner air above the Saudi desert also means Solar Impulse's motors will have to work harder to propel the vehicle forward.

This will require careful management of the energy reserves in the plane's lithium polymer batteries, to be sure they can sustain the aircraft through the night hours, BBC quoted the pilot as saying. The Solar Impulse has covered some 30,000 km in its quest to become the first plane to circle the world using no fuel, just the energy from the Sun.

The Cairo-Abu Dhabi flight marks the 17th and final segment in the journey, which has included crossings of the Pacific and Atlantic oceans.

Piccard has alternated pilot duties with his friend and business partner Andre Borschberg.