The no fuel aeroplane, Solar Impulse, left the Egyptian capital, Cairo, on its global tour. The aircraft was supposed to take about 48 hours to reach Abu Dhabi, UEA – the place it began the expedition in March 2015.
Pilot Bertrand Piccard, his flight ought to be fairly simple, although his team has some concerns about how the heat in the Middle East may affect the plane.
The warmer, thinner air above the Saudi desert also means Solar Impulse’s motors will have to work harder to actuate the vehicle forward.
This requires for careful management of the energy reserves in the plane’s carbonate molecular batteries, to be sure they can subsist the aircraft through the night hours.
“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,” Mr Piccard said.
Solar Impulse covered around 30,000km in its pursuit to become the first plane to circle the world without 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. Mr Piccard has alternated pilot duties with his friend and business partner Andre Borschberg.
The pair had hoped to clear the challenge last year but progression was not quite swift enough to get the best of the weather in the Northern Hemisphere’s summer.
And when battery damage was sustained on an epic five-day, five-night passage over the western Pacific in June/July 2015.
Mr Piccard said he vowed then that “there had to be another way”.
He further said: “I make the bet that in 10 years we will have electric aeroplanes flying with 50 passengers for short- to medium-haul flights.”
“You can fly with no pollution and no noise – purely electric – and landing in urban airports, making no disturbance for the neighbours.
“So, it will be a market for aviation and transport. And maybe sometimes people will say this all started with a crazy idea of flying around the world in a solar aeroplane, and the outcome was useful for everyone.”
Their plane is wider than a 747 jumbo jet but weighs just 2.3 tonnes, which proffer some special challenges:
The aircraft is very responsive to the weather conditions, but its solar cell and battery improvement is very high. This means it can stay aloft for many days and nights. The pilot is allowed to catnap of up to 20 minutes. The cockpit is little bigger than a public telephone box