Helios Aircraft Weight 2,048 pounds (929 kg) Wingspan 247 ft (75.3 m) Length 12 ft (3.7 m) Wing Area 1,976 square ft (183.6 m 2 ) Propulsion 14 brushless, 2-horsepower, direct-current electric motors Range 1 to 3 hours in prototype tests 6 months when fully operational Speed 19 to 25 mph (30.6 to 40.2 kph) The Helios prototype is constructed out of materials such as carbon fiber, graphite epoxy, K