Solar Impulse has chalked up another 1600km in its bid to circumnavigate the globe. The all-electric solar-powered aeroplane successfully flew from Phoenix to Tulsa, landing in the dead of night. Image: Solar Impulse
The flight took just over 18 hours, with the aeroplane -- under the control of Bertrand Piccard -- managing to hit an average speed of just 87km/h. The aeroplane uses 17,000 solar panels on its wing to charge 942kg of lithium battery, so there's a lot of weight to carry, hence the slow speeds.