Unmanned aerial vehicles (UAVs) supplied with thousands of hours of electricity—this may be the future thanks to a small generator with a cooled, radial gas turbine.
From engineers at Southwest Research Institute (SwRI), this development can improve upon current UAV turbines that only provide a few hundred hours of power before succumbing to wear and tear.
“This turbine is part of a generator that’s similar to what the average person might use to generate electricity in their home when the power goes out,” says David Ransom of SwRI’s Mechanical Engineering Division. “The version we’re creating is more compact and efficient, tailored to the needs of a small, unmanned aircraft.”
To clarify, a turbine is a type of mechanical device that produces electrical power when it’s used with a generator. In current miniature systems, the turbine is exposed to high temperature gas during the generator’s combustion process, which causes damage.
“The hotter the turbine gets, the better its performance,” says Ransom. “But these smaller turbines can’t survive the temperature, so we’ve designed one that has tiny airflow passages that cool the turbine without sacrificing the power of its performance. Normally with small turbines you have to make a choice between performance or reliability, but we’re making it possible to have both.”
To make this possible, SwRI engineers scaled down their previous high temperature turbine airflow experience on larger projects, such as airplanes and power plants, for a UAV-sized design. They used a selective laser melting (SLM) machine, which builds metal layer by layer, to create small, complex designs with internal air passages.
“Generators that provide power to us and to big aircraft already have cooled turbines, whereas a generator of this size for a small craft does not,” says Ransom. “It’s an exciting engineering challenge, and having the ability to print parts with the SLM machine is a real advantage.”
SwRI formed an internal R&D program known as the Metals Additive Kickoff Emphasizing Research Synergies (MAKERS). Tasked with utilizing the new SLM machine, this UAV turbine is the first product under the MAKERS initiative.
