German group Lange Aviation has developed the Antares 20E electric self-launching sailplane, which the company claims will be the ‘motorglider of the future’.
The plane has a wingspan of 20m and uses an almost-silent propulsion system powered by a 42kW brushless electric motor and a 2m-diameter propeller that extends above the fuselage centre section.
According to its developers, the use of a Saft customer-designed rechargeable lithium-ion (Li-ion) battery system has doubled the launch height of the plane. The entire battery system weighs 80kg and is split into two packs positioned in the leading edges of both inner wings.
Each pack consists of 36 cells in series, divided into 12 three-cell modules. Together, both battery packs provide an operating voltage of 212V to 288V, with each cell monitored and controlled for maximum performance.
The Antares can reach 1,000m, which is twice the height achieved by a good winch launch, in less than four minutes. Each extra take-off costs approximately 100m from the final climb altitude. Partial charges and discharges have no adverse impact on the battery life. The battery system provides 13 minutes of power once it has received a full nine-hour charge, which allows the Antares 20E to fly for around 3,000m after take-off.
Axel Lange, chief executive of Lange Aviation, said: ‘The Antares demonstrator LF-20E flew on Ni-MH [nickel-metal-hydride] batteries and performed well. But the extra power available when we switched to the Saft Li-ion batteries has enabled us to more than double the launch height using a battery system that weighs 26 per cent less.’