DARPA Announces New Flying-Wing X-Plane: XRQ-73

The Defense Advanced Research Projects Agency has assigned the designation XRQ-73 to its newest “X-plane,” a prototype flying-wing autonomous reconnaissance aircraft with extra-quiet propulsion that is expected to fly this year, announced the agency on June 24.

The new aircraft also carries the program acronym SHEPARD, for “Series Hybrid Electric Propulsion AiR Demonstration,” and is being developed by Northrop Grumman and its subsidiary Scaled Composites. It is powered by a hybrid electric system that converts fuel into electrical energy and is part of DARPA’s X-prime program.

The program builds on hybrid technologies and other components developed under the previous “Great Horned Owl” project managed by the Air Force Research Lab and the Intelligence Advanced Research Projects Agency, DARPA said. The Office of Naval Research and AFRL are also partners on SHEPARD.

Other companies involved include Cornerstone Research Group, Inc.; Brayton Energy, LLC; PC Krause and Associates and EaglePicher Technologies, LLC, DARPA said.

DARPA revealed that the books. Group 3 UAS also fly below 18,000 feet and at speeds between 100 and 250 knots. The then-unnamed plane was scheduled to fly sometime in 2023, but DARPA did not explain why it did not.

The Great Horned Owl project began in 2011 and had the designation XRQ-72. It used top surface thrusters and was therefore not stealthy, but the XRQ-73 is a flying wing with engines buried in the planform, clearly intended to have low radar observability in addition to reduced noise. The GHO was required to be powered by gasoline or diesel, but it is unclear whether this requirement also applies to the SHEPARD. Most details of the program remain classified, but the hybrid-electric approach is intended to significantly extend the travel and parking time of a drone of this class.

DARPA said the XRQ-73 could be “rapidly operational.” The SHEPARD effort has been underway for about four years.

The SHEPARD vehicle will have “operationally representative fuel fraction and mission systems, while remaining below the weight limit for Group 3 UAS,” DARPA said on its website.

A 2011 IARPA program briefing slide noted that noise is the “number one” problem for low-flying UAS. A hybrid power approach was chosen to eliminate gearbox noise on the GHO.

Scaled Composites takes care of manufacturing; Northrop and its subsidiary Scaled are also working on the Defense Innovation Unit/Air Force Blended Wing Body demonstrator, considered a potential stealth transport prototype.

SHEPARD program manager Steve Komadina said in a DARPA press release that the idea behind DARPA’s X-prime program “is to take emerging technologies and reduce integration risks at the system to rapidly mature a new missioned long-endurance aircraft design that can be fielded quickly. »

The XQR-73 program “matters a specific propulsion architecture and power class as an example of potential benefits to the Department of Defense,” Komadina said.

DARPA did not say whether the XQR-73 would be formally connected to the Air Force’s ongoing collaborative fighter jet projects, but a Pentagon official said those efforts were being coordinated to find “aligned technologies.” .

SHEPARD “is an existing option” for AFRL’s Great Horned Owl contract, Komadina said in an undated description on the DARPA website. The SHEPARD will leverage what has been learned about the GHO’s hybrid electric architecture and some of its component technologies, and rapidly evolve a new mission-focused aircraft design that can be fielded with the “objective of a first flight in 20 months”.