US Naval Research Office Taps Parallel Flight, Alpha for Heavy-Fuel UAS

California-based Parallel Flight Technologies and Spanish firm Alpha Unmanned Systems have entered into a strategic collaboration to develop engine solutions for autonomous aviation under a US Office of Naval Research (ONR) program.

For the initiative, Parallel Flight will modify its patented Hybrid Electric Multirotor propulsion system for heavy-fuel compatibility, extending unmanned aerial system (UAS) range and performance across complex domains.

The resulting engine will be fitted with Parallel Flight’s proprietary Firefly quadcopter drone, selected under a 2025 ONR deal to assemble a tailor-made platform for military logistics, littoral surveillance, and research.

Firefly is promoted as a “heavy-lift workhorse” that can move equipment weighing up to 100 pounds (45 kilograms), supply 2 kilowatts of continuous power to payloads, and travel at up to 100 miles (161 kilometers) per hour.

It can refuel in under five minutes, deploy from undeveloped surfaces, and be transported via a pickup truck.

Leveraging Heavy-Fuel Expertise

Throughout the effort, Alpha will apply its know-how in heavy-fuel propulsion, shaping the development and validation of the Parallel Flight’s hybrid architecture for ONR requirements.

The Madrid-based company holds over 10 years of experience with fuel-powered rotary-wing UAS for integration and real-world operations in support of defense, maritime, and security tasks.

“The use of heavy-fuel engines is essential for unmanned aircraft deployed in challenging defense and maritime operating environments,” said Álvaro Escarpenter, CTO at Alpha Unmanned Systems.

“We are proud to support Parallel Flight’s efforts and contribute our expertise … to this important program.”