Battery-powered aircraft crosses the Alps

July 08, 2015 // By Christoph Hammerschmidt
Researchers of the Institute of Aircraft Design in Stuttgart showed the practicability of battery powered aircraft in a flight across the Alps mountains – a first time for a battery-powered plane. The flight also marks a milestone in the quest for energy-efficient and carbon-neutral aviation.

Past saturday morning, the electric aircraft “e-Genius” flew from the airfield Hahnweide near Stuttgart over the Alps to Italy. On its way to the airfield Calcinate del Pesce in Northern Italy the aircraft covered a distance of 320 km (200 miles) and climbed to an altitude of 4000 m (13.200 feet) in order to safely pass the summits of the Swiss Alps.

The airplane represents a state-of-the art touring glider in most of its design characteristics – two pilots in a side-by-side seat arrangement, wing span of 16,9 metres and a glide ratio of 34. The most significant difference: The plane is equipped with a 60kW electric motor that drives a constant-speed propeller, located at the top of the vertical tail fin. The energy is stored in four lithium ion battery packs with a total capacity of 56 kWh.

During its record flight the e-genius was flown by pilots Klaus Ohlmann and Ingmar Geiß of the University of Stuttgart. e-Genius arrived at its destination in little over two hours. On the same day, the batteries were recharged and e-Genius headed back to Stuttgart in the afternoon. This was a particular challenge because of the steep profile of the Swiss Alps. In order to have enough time to climb, a flight path across the Gotthard pass was chosen, which meant the aircraft had to cover an even longer 365 km distance back to its home airfield.

Besides emitting extremely little amounts of carbon gas, the energy consumption of the flight showed the impressive potential of this aircraft technology: for both flights combined, only 83 kWh were used, the energy equivalent of 9.2 litres of gasoline. This leads to a total energy expense of only 21€ for the whole trip, assuming current electricity prices in Germany.

The electric aircraft e-Genius was developed at the University of Stuttgart and is in a flight test program since May 2011. The goal of the project