A compact microturbine capable of generating 30 kW and weighing 150 lb. is undergoing certification for application as a power source for multiple applications including a general aviation auxiliary power unit or as a turbogenerator for advanced air mobility vehicles, and uncrewed aircraft systems.

Developed by Miami-based KW Micro Power, the gearless, oilless device measures 15 in. in width and is only 30 in. in length. Configured with single centrifugal compressor and turbine stages, the engine has an operating speed of 90,000 rpm and can run on Jet A, JP8 and diesel, says Enrique Enriquez, president of KW Micro Power. The unit’s ability to operate on diesel and Jet A makes it likely it will also run easily on sustainable aviation fuel, he adds.

Innovations include extensive use of foil-air bearings—a type of air bearing in which the shaft is supported by a compliant foil journal lining, as well as 3D-printed components with internal passageways for advanced heat exchanger capability. Fuel is passed through a hollow generator and inlet housing to provide cooling.

“Normally this housing would be running at about 300F, but the fuel brings the temperature down to about 86F. Before all that energy was dissipated into space but it's now in the fuel, which makes the whole cycle more efficient. We do something very similar with our combustor which picks up energy from the preheated air from a number of 3D-printed channels. It is free energy that nobody was using,” says Enriquez.

The unit, which is designed for simple maintenance with few parts, is electronically controlled and can be ganged together with sister units for higher power requirements, he adds. The device is also being evaluated for potential military applications including as a power source for direct energy weapons.