Unmanned aerial vehicles (UAVs), commonly called drones, are quickly becoming part of everyday life. In the past few years, as prices have dropped and control systems have become easier to operate, use of small UAVs has extended from government agencies and niche hobbyists to industries like agriculture, insurance, journalism, and more.

Yet, until now, small UAVs have run solely on batteries — limiting their flight time to a matter of minutes. Chris Hagen, associate professor of energy systems engineering at OSU-Cascades, in Bend, set out to change that. 

Hagen and his team of researchers have developed a prototype hybrid engine for small UAVs capable of keeping them aloft for extended periods of time. The team’s concept miniaturizes technology that has been proven in larger vehicles, including aircraft.

The prototype, which was supported by funding from the MJ Murdock Commercialization Initiation Program and the OSU Venture Development Fund, combines a small gasoline engine with an electric motor. The engine powers a generator that charges the batteries, which in turn power the electric motors attached to the propellers. 

So far, drones with this hybrid system have flown for over an hour without needing to refuel. The goal is to increase flight time even more.

“The UAV industry is growing by leaps and bounds,” said Hagen. “Having a powertrain that extends the range of these vehicles is a great enabler for adoption.”

This new technology could enable a number of applications, such as research and search and rescue. For example, drones that stay aloft longer could allow first responders greater capability to locate and bring essentials to people in need of immediate help in hazardous environments.

In addition to greater endurance, Hagen’s team’s powertrain design makes the drones more effective. With enough power for vertical takeoff and landing, it eliminates the need for a runway and makes it easier to send help as soon as it’s needed.

While he continues to refine the prototype, Hagen is getting the word out about his product. By working with SOAR Oregon, a nonprofit economic development organization dedicated to drone expansion, he plans to connect with established drone businesses and build relationships with first responders. Hagen is also protecting his engine designs with patent applications through Oregon State University’s Office for Commercialization and Corporate Development. 

Oregon State has also provided Hagen access to talented, enthusiastic undergraduate and graduate student researchers.  

“I have to thank Nancy Squires [senior instructor of mechanical engineering] and the OSU chapter of the American Institute of Aeronautics and Astronautics, which has encouraged both former graduate student Sean Brown (now an associate engineer at SpaceX) and now James Benbrook to join my group and work on UAV technology,” he said.

Hagen wants his drones to go even further. He is currently targeting them for use in other applications, like spotting forest fires and conducting wildlife research. And in the future, he hopes to make hybrid cars drive longer on electricity and develop mini-generators for home use.