The solar-powered aircraft designed for the first round-the-world flight attempt without any fuel was unveiled by engineers in Switzerland yesterday.
The team behind Solar Impulse 2 hope the 72m-wingspan single-seater aircraft will next year fly the approximately 35,000km (22,000 miles) route around the globe, broken into around 10 stages including a five consecutive day-and-night trip across the Pacific.
The flight attempt, spearheaded by engineer André Borschberg and psychiatrist Bertrand Piccard, will be the culmination of 12 years of design, engineering and testing that included the first 24-hour solar-powered flight in predecessor craft Solar Impulse 1.
‘With eight world records for Solar Impulse 1, the first solar aircraft capable of flying during the night, crossing two continents and flying over the United States, we have shown that clean technologies and renewable energies can accomplish the impossible,’ Piccard said in a statement.
Borschberg added: ‘Solar Impulse 2 will have virtually unlimited autonomy, and now we need to make sure the pilot is as sustainable as his aircraft. This is why the round-the-world flight will be as much a human as a technological feat.’
The 2.3 ton carbon-fibre aircraft uses over 17,000 solar cells to power four brushless motors and charge four batteries, which enable the craft to fly at speeds between 36kph (22mph) and 140kph (87mph) during both day and night.
A single pilot will control the craft from a 3.8m3 unpressurised, unheated cockpit at altitudes of up to 8,500m (27,000ft), relying on oxygen supplies and high-density thermal insulation to survive temperatures of between 40°C and -40°C
The craft has a wingspan greater than that of a Boeing 747 but weighs less than one per cent of the jumbo jet – closer to that of a large car.
‘What we have here is an extremely lightweight structure – a minimal frame made of carbon-fibre reinforced polymer elements with a high-tech film just 0.2 millimetres thick stretched over it,’ said Yves Govers from the German Aerospace Centre (DLR), which carried out vibration testing for Solar Impulse 2.
Test flights are due to take place in May, followed by training flights over Switzerland and then the round-the-world attempt in March 2015, which be carried out with the support of Swiss-based power systems company ABB.
The route will take Solar Impulse 2 from a launch site in the Gulf area and fly over the Arabian Sea, India, Burma, China, the Pacific Ocean, the United States, the Atlantic Ocean and Southern Europe or North Africa before returning to the departure point.