Droner - Optionally manned overvåking som går på bennselceller - AW&ST

Antares E2 Brings New Benefits To Unmanned Surveillance Graham Warwick Building on its experience producing electrically powered motor gliders, Germany’s Lange Aviation set out to develop a surveillance platform combining long endurance and low emissions with the high reliability required to carry expensive payloads and the flexibility of being optionally piloted. The result is the Antares E2, a fuel-cell-powered aircraft with 40-hr. endurance when flown unmanned. The prototype was unveiled at the Aero 2018 general aviation show in Friedrichshafen, Germany, on April 18, and is expected to make its first flight in June. The E2 is a follow-on to the Antares DLR-H2, developed with German aerospace center DLR. Based on an Antares 20E motor glider, the H2 first flew in 2009 and was the first piloted aircraft to be powered exclusively by fuel cells. The H2 used pressurized hydrogen as the fuel.

 

Lange’s prototype Antares E2 was unveiled at the Aero 2018 show in Friedrichshafen, Germany. Credit: Lange Aviation

 

The Antares E2 uses methanol as the fuel. This is converted to hydrogen for use in the fuel cells by catalytic steam reformers. The aircraft is designed with high redundancy and reliability, as the payloads carried by surveillance platforms can cost 2-3 times as much as the airframe itself. The E2 has six reformed methanol fuel cells powering six electric motors via six DC/DC converters, as well as a quadruplex-redundant flight control system. The aircraft can maintain horizontal flight on just two of the six motors and three of the six fuel cells, Lange says.

 

Propellers are mounted above the wing in clear air to improve aerodynamics and reduce noise. Credit: Lange Aviation

 

Fuel cells minimize fuel consumption and emissions, but the aircraft must run for an hour before launch to heat the cells to their 170C (330F) operating temperature. Fuel cells are also slow to respond, so a lithium-ion battery provides additional power for takeoff, climb and dynamic flight. The 6.7-kW fuel cells are housed in two large pods under the inboard section of the 23-m-span (75.6-ft.) wing, and 300 kg (660 lb.) of methanol fuel is stored in outboard wing pods. The battery—24 modules each with three cells—is installed in the leading edge of the wing.

 

Methanol fuel is steam reformed into hydrogen for use in the fuel cell, pictured next to the aircraft. Credit: Aero 2018

 

The 15-kW motors and propellers are mounted on struts high above the trailing edge of the wing. This arrangement results in no aerodynamic interference from the props on the airflow over the upper and lower surfaces of the wing, says Lange. Payloads can be installed in forward- and mid-fuselage bays and the outboard wing pods. The Antares E2 can carry 200 kg of payload and provide 4 kW of power for sensors and other systems. This is more than enough for the civilian applications at which the E2 is aimed, says Lange. The E2 will fly initially with a pilot, but Lange plans to develop it as an unmanned aircraft for long-endurance missions including maritime surveillance, security, border control and surveying. The company plans to certify the aircraft to European CS-23 regulations, although the airworthiness rules for unmanned operation are not yet in place.