DARPA demonstrates experimental hybrid-electric propulsion UAV

DARPA's XRQ-73 SHEPARD hybrid-electric experimental aircraft takes off at Edwards Air Force Base, California. (Northrop Grumman)

The US Defense Advanced Research Projects Agency (DARPA) announced on 6 May the first flight of its experimental hybrid-electric, unmanned aerial vehicle (UAV), the XRQ-73.

The XRQ-73, created as part of DARPA's Series Hybrid Electric Propulsion AiRcraft Demonstration (SHEPARD) programme, was created in collaboration with the Air Force Research Laboratory (AFRL) and Northrop Grumman.

The first flight, conducted in April 2026 at Edwards Air Force Base in California, marks a step forward for the programme and its objective of producing an aircraft capable of hybrid-electric propulsion.

Part of what DARPA calls an “X-prime program”, SHEPARD “takes emerging technologies and burns down system-level integration risks to provide a minimum viable product to meet an urgent operational need”, former SHEPARD program manager Steve Komadina said in 2024.

US Air Force (USAF) Lieutenant Colonel Clark McGehee, SHEPARD programme manager, said in a 6 May DARPA statement that the XRQ-73's architecture “paves the way for new types of mission systems and delivered effects”, as new designs that combine fuel efficiency, lower emissions, lower radar signature, and operational flexibility become feasible due to the technological developments of the XRQ-73.

SHEPARD was originally slated to demonstrate its first flight in late 2024, leveraging lessons from AFRL/IARPA's Great Horned Owl (GHO) contract that was designed to produce an unmanned air vehicle capable of extending the endurance and payload capabilities of intelligence, surveillance, and reconnaissance (ISR) UAVs.

The XRQ-73 is a Group 3 UAV that weighs approximately 1,250 lbs, larger in scale and scope than the XRQ-72 X-plane it derives from, but below the Group 3 weight limit for unmanned aircraft.