Three Hummingbird vertical takeoff and landing unmanned aerial systems are being introduced by Reference Technologies, the company reports.

The Model 1 Hummingbird is a battery powered aircraft with a medium flight duration and light payload capacity. Model II, a long flight duration and high payload aircraft, uses a gas-powered electrical system to power to six external rotors surrounding a 19-inch electrically powered central ducted fan with two counter rotating fans.

The Model III is an enhanced version of the Model I with eight external rotors in conjunction with a 24" central ducted fan providing extended flight duration and payload capacity, Reference Technologies said.

"After two and a half years of development and testing, the Hummingbird aircraft will begin customer deliveries in Q3 of this year," said Allen Bishop, founder and president of Reference Technologies.

The Hummingbirds, which are being introduced next week at the 2014 AUVSI Convention in Orlando, Fla., have flight times of more than five hours. Airframes feature multiple hard points which can carry/release mission specific payloads.

Direct flight control and pre-programmed flight plans are managed through ground control interfaces, such as Intel, Android and iOS-based devices, the company said.