New Hybrid-Electric Technologies for UAVs Under Development

By Mike Ball / 09 Oct 2020

Hybrid-electric UAV

LiquidPiston has received a Small Business Innovation Research (SBIR) Phase I grant from the U.S. Army to develop its X-Engine rotary propulsion system as a hybrid-electric platform for UAVs (unmanned aerial vehicles). The company was also named one of 12 winners in the U.S. Army xTechSearch 3.0, a competition for innovative technology solutions that can help solve key Army challenges, for its X-Engine configured as a high-efficiency auxiliary power unit (APU). These new aviation applications the X-Engine technology demonstrate the versatility of the system and its ability to provide compact, fuel-efficient power for manned or unmanned aircraft using military-grade heavy fuels such as JP8.

The rotary X-Engine operates on the company’s patented High-Efficiency Hybrid Cycle (HEHC), and its compact size and fuel efficiency make it an ideal power source for a hybrid-electric propulsion platform. Such a system would allow minimization of heavy, low energy density onboard batteries and be particularly suited for UAVs with Vertical Take Off and Landing (VTOL) capabilities. These UAVs would also have the ability to cruise in “quiet mode” using electric-only power, with the ability to restart the engine mid-flight, enabling more efficient fuel usage and stealthier missions.

The X-Engine, when matured and deployed, will help to provide the increasing power requirements for direct and hybrid electric propulsion for the US Army Future Tactical UAS (FTUAS) and other DoD UAS programs as well as Auxiliary Power Units (APUs), Supplemental Power Units (SPUs) and Power & Thermal Management Systems (PTMS) for manned rotorcraft and fixed wing aircraft.

Alec Shkolnik, CEO and co-founder of LiquidPiston, commented: “This SBIR award and xTechSearch 3.0 innovation competition showcases the Army’s interest in innovative, fuel-efficient power sources to deliver the power needed to support Future Vertical Lift (FVL) Modernization Priorities. When we reimagined the rotary engine with the X-Engine, we knew it could be used to improve power generation in a number of different ways, given its high power-to-weight, efficiency, and ability to run on heavy fuel including Jet-A / JP8 fuel which the Army wants to use exclusively. The versatility of LiquidPiston’s X-Engine enables the company to provide hybrid-electric power generation in various form factors, which makes it uniquely suited to serve not just FVL, but all 6 of the Army’s modernization priorities.”

Dr. William Cohen, Chief Technology Officer of the U.S. Army Assistant Secretary of the Army (Acquisition, Logistics and Technology), said: “Advanced power generation and alternative fuels are critical for the Army, and we continuously seek new technologies that can materially improve our ability to execute national security missions. Reliable engine technologies that offer a wide range of sustainable applications, from UAVs to auxiliary power units for air and land vehicles, can increase endurance and lessen reliance on contested or extended supply lines. Potential benefits include increased reliability and access to power, increased redundancy within the power distribution network, reduced logistics footprint associated with fuel distribution, and extended operational reach.”

Find manufacturers of Engines & Propulsion Systems for UAVs >>

Posted by Mike Ball Mike Ball is our resident technical editor here at Unmanned Systems Technology. Combining his passion for teaching, advanced engineering and all things unmanned, Mike keeps a watchful eye over everything related to the unmanned technical sector. With over 10 years’ experience in the unmanned field and a degree in engineering, Mike’s been heading up our technical team here for the last 8 years. Connect & Contact