Lange Aviation explained the large glider-like machine on display at the 2018 Aero Expo this way: “During this year’s AERO in Friedrichshafen, a mock-up of the Antares E2 was displayed publicly for the first time by our sister company, Lange Research Aircraft GmbH. The Antares E2 is an aircraft with an extreme endurance and very high reliability, which has been designed primarily to address maritime monitoring tasks such as fishery control. In order to fulfill the design goals, a novel propulsive system using six fuel-cell systems and six over-wing propulsors has been developed.
A Large, Heavy Machine Beyond Glider Status
Weighing in at a hefty 1,650 kilograms (3,630 pounds), the Lange E2 carries that weight on a 23 meter (75.45 feet) wingspan. Part of that is the 300 kilograms (660 pounds) of methanol that powers the six 6.7 kilowatt (8.98 horsepower) fuel cells that in turn power the six 15 kilowatt (20.1 hp.) motors.
High wing loading brings high speed, the E2 capable of a top rate of 135 knots (155.25 mph) and a stall speed of 62 knots (68.2 mph). Clean design and the efficiency of fuel cells enables an endurance of up to 40 hours, a range of 5.400 kilometers (3,348 miles). It can carry a 200 kilogram (440 pound) payload to 20,000 feet and power its sensors and communications links with a four-kilowatt, 28 Volt DC power supply.
As noted on Lange’s web site, “’The E2 is only a glider at first glance,’ says CEO Axel Lange, in fact, it is a flying sensor platform for research purposes, which can remain in the air with fuel cell drive about 40 hours in the air….’” Initial tests will be performed with a manned version, but later, the E2 will fly autonomously on missions such as border patrols or identification of marine pollution.
Lange emphasizes redundancy onboard the E2. Besides a quadruple redundant main computer, systems include:
- 6 x fuel cells with reformer and DC / DC
- 6 x propulsors with integrated inverters
- 2 x propulsive power bus, reconfigurable
- 3 x system power bus, SOH voting
- 9 x data-bus in three branches (CAN)
Methanol Fuel Cell Economy
The Antares E2’s energy supply uses fuel cells with an integrated methanol reformer system claimed to be “superior to other forms of energy supply, especially when there is a long-term and constant need for energy. This is because the reformer allows the extraction of much higher energy than standard burner motors.”
For additional energy during maneuvers such as takeoffs, the system uses lithium-ion battery modules mounted in the wing inner nose. According to Lange, “Each cell is voltage and temperature-monitored with multiple redundancies. In addition, the modules have battery-heating systems in order to allow use at optimal temperature ranges.”
The fuel cell system, with an inverter from Elmo Motion Control, was tested at Lange. Five other systems built by Serenergy passed the Factory Acceptance Test. All the DC-DC converters were therefore built and successfully tested.
Efficiency and Economy for Future Missions
Lange Research notes, “Observation and surveillance missions are mostly implemented by using conventional, ie petrol-driven, aircrafts. The Antares E2 wants to make the implementation of missions much more efficient due to its lesser fuel consumption and lower costs of preparation. This new economic efficiency also wants to open the market for new missions, which are not yet ready for their high cost.”