at the same period than with NiCad batteries. Under the direction of Freddie To, an architect and member of the Kremer prize committee, the Solar One was designed by David Williams and produced by Solar-Powered Aircraft Developments. A motor-glider type aircraft originally built as a pedal-powered airplane to attempt the Channel crossing, the airplane proved too heavy to be successfully powered by human power and was then converted to solar power, using an electric motor driven by batteries that were charged before flight by a solar cell array on the wing. The maiden flight of Solar One took place at Lasham Airfield, Hampshire, on June 13, 1979. The MacCready Gossamer Penguin first flew carrying a pilot in 1980. The MacCready Solar Challenger was first flown in 1980, and in 1981 flew 163 miles from Pontoise – Cormeilles Aerodrome, north of Paris, France to Manston Royal Air Force Base in Manston, United Kingdom, staying aloft 5 hours and 23 minutes, with pilot Stephen Ptacek at the controls. The human piloted Solair 1, developed by Günther Rochelt, flew in 1983 with notably improved performance. It employed 2499 wing-mounted solar cells. The German solar-powered aircraft "Icaré II" was designed and built by the institute of aircraft design (Institut für Flugzeugbau) of the University of Stuttgart in 1996. The leader of the project and often pilot of the aircraft is Rudolf Voit-Nitschmann, the head of the institute. The design won the Berblinger prize in 1996, the EAA Special Achievement Award in Oshkosh, the Golden Daidalos Medal of the German Aeroclub and the OSTIV-Prize in France in 1997. Solar Impulse 2 is powered by four electric motors. Energy from solar cells on the wings and horizontal stabilizer is stored in lithium polymer batteries and used to drive propellers. In 2012 the first Solar Impulse made the first intercontinental flight by a solar aircraft, flying from Madrid, Spain to Rabat, Morocco. Completed in 2014, Solar Impulse 2 carried more solar cells and more powerful motors, among other improvements. In March 2015, the aircraft took off on the first stage of a planned round-the-world trip, flying eastwards from Abu Dhabi, United Arab Emirates. Due to battery damage, the craft halted at Hawaii, where its batteries were replaced. It resumed the circumnavigation in April 2016 and reached Seville, Spain, in June 2016. The following month it returned to Abu Dhabi, completing its circumnavigation of the world. General aviation