Solar Impulse has started taking its HB-SIA airplane which uses photovoltaic (PV) cells to keep it going for spins to make sure that everything works fine and dandy, fleshing out what used to be theoretical. Part of the “Solar Impulse Project,” the HB-SIA measures 21.85m in length, 63.4m in wing length and 6.4m in height. The main wing and horizontal tail holds 11,628 pieces of SunPower Corp’s photovoltaic (PV) cells which will power the quartet of electrically-driven engines that are able to churn out a maximum output of 7.5kW (10hp) and an average output of 6kW. This won’t break any speed records though, with an average flight speed of 70km/h.