Solar Impulse moved a step closer to a planned round-the-world flight next year with the maiden flight on 2 June of the critical second prototype – the first solar-powered aircraft designed to cross oceans.

The roughly 2h flight of the Solar Impulse 2 – registered as HB-SIB ­– from the Solar Impulse base in Payerne, Switzerland, was described as “successful”.

Markus Scherdel, who piloted the first flight of the HB-SIA prototype five years ago, landed the second, significantly larger aircraft at 07:40 at the Payerne airport.

The second prototype is designed with a 72m (236ft) wingspan, 13.6% larger than the wingspan of HB-SIA.

About 17,000 photovoltaic cells embedded in the wing of HB-SIA supply energy to four, 17.5hp electric motors. The solar cells also recharge lithium ion batteries weighing 633kg during the day, which provides the renewable fuel for the electric motors at night.

Despite sharing the wingspan of a Boeing 747-400, Solar Impulse lists the overall aircraft weight of HB-SIB at 2,300kg (5,070lb), or roughly the same as a car.

While the first prototype proved that overland flight by a solar-powered aircraft was possible, the second aircraft is intended to prove the viability of flying over oceans.

The flight path envisioned by Solar Impulse founder Bertran Piccard for the round-the-world trip next year begins in the middle latitudes of the Persian Gulf, then moves east. In four or five hops, Solar Impulse intends to cross Asia, the Pacific Ocean, North America, the Atlantic Ocean and Europe.

Source: FlightGlobal.com