Designs for weaponized long-endurance X-plane

DARPA's ANCILLARY program aims to develop and demonstrate an X-plane with the critical technologies required for a leap ahead in long endurance, and VTOL UAS performance. The UAS would be able to launch and recover from ship flight decks and small austere land locations in adverse weather without additional infrastructure equipment, thus enabling expeditionary deployments and locally commanded responsive intelligence, surveillance, reconnaissance and targeting (ISR/T) with unique payload capabilities. Unlike large VTOL systems, the small UAS size would allow many aircraft to be stored and operated from one ship, creating a tactical beyond-line-of-sight, multi-intelligence sensor network capability.

“A network of these small UAS can be launched from a ship to provide beyond-line-of-sight F2T2 (find, fix, track, target) of surface vessels of interest for the ship commander,” Komadina said. “While we anticipate this effort is most likely to support Navy and Marine missions, we have found other services are very interested in the capabilities this technology can bring to diverse missions, including logistics, strike, and special uses by the Army, Air Force, Special Operations Command, and Coast Guard.”

“We expect the operational capabilities provided by ANCILLARY will be augmented by other technologies being developed within the Department of Defense’s various research and engineering organizations, such as advances in sensors, electronic warfare, and especially autonomy and artificial intelligence,” said Komadina.

Upon entering the latest stage of the ANCILLARY project, renowned companies like AeroVironment, Griffon Aerospace, Karem Aircraft, Method Aeronautics, Northrop Grumman, and Sikorsky are dedicating substantial efforts to refine and advance their designs for the cutting-edge X-plane. Their primary focus is on minimizing risks and conducting comprehensive analyses to propel the development of this innovative aircraft.

The U.S. military's commitment to elevating the payload capacity and range/endurance of small, ship-launched unmanned aerial systems (UAS) demonstrates a pursuit of pioneering technological solutions. The project seeks to achieve various capabilities, including vertical take-off and landing, advanced propulsion, and controls while aiming to eliminate the necessity for special infrastructure, thus ensuring adaptability across diverse environments and weather conditions.

The operational capabilities provided by ANCILLARY are anticipated to receive further enhancements from progress in sensors, electronic warfare, autonomy, and artificial intelligence, stemming from multiple research and engineering organizations within the Department of Defence.

Northrop Grumman, a reputable aerospace and defence technology company, leverages its extensive operational experience with the U.S. Navy to contribute significantly to the project. In parallel, other companies such as AeroVironment and Sikorsky have introduced advanced designs like the Wildcat and battery-powered aircraft, featuring pioneering take-off and propulsion attributes tailored to navigate the challenging conditions encountered by various Navy ships.

The meticulous testing and development efforts of these companies are projected to lay the groundwork for the future utilization of advanced X-planes, potentially reshaping the landscape of military operations. The forthcoming X-plane flight tests anticipated for early 2026 mark a crucial milestone in the evolution of these cutting-edge aircraft, signifying a seismic shift in military operations.

Sikorsky

Sikorsky, a Lockheed Martin company, is currently engaged in a series of flight tests aimed at refining the control laws and aerodynamics of a groundbreaking vertical takeoff and landing uncrewed aerial system (VTOL/UAS). These flight tests serve the purpose of validating the efficiency and scalability of a distinctive twin proprotor 'rotor blown wing' configuration. This configuration allows the aircraft to take off and land vertically like a helicopter, and seamlessly transition to horizontal forward flight for extended missions, such as intelligence, surveillance, reconnaissance, and targeting.

The ongoing flight tests align with the objectives of the Ancillary initiative by the Defense Advanced Research Projects Agency (DARPA), which is focused on developing a Class 3 UAS VTOL X-Plane capable of operating in diverse weather conditions from ship decks and unprepared surfaces without the need for specific infrastructure. Sikorsky is among the select group of competitors chosen to advance their UAS conceptual designs into the next phase of development.

The term 'rotor blown wing' pertains to the continuous airflow generated by the proprotor wash across the wing structure. Sikorsky opted for this design to minimize wing drag during hover mode and the transition to forward flight, while simultaneously enhancing cruise efficiencies and endurance.

This innovative design represents just one of several ways in which Sikorsky continues to push the boundaries of 21st Century Security technologies and advancements, as highlighted by Igor Cherepinsky, the director of the rapid prototyping group Sikorsky Innovations.

Cherepinsky emphasized, "Flight tests are being conducted to confirm the high stability during vertical launch and landing, as well as the efficient cruising capabilities of our tail-sitting rotor blown wing UAS. The critical factors enabling flight manoeuvrability and the future scalability of the vehicle are our MATRIX autonomy flight control system and an articulated rotor system akin to those used in conventional helicopters."
The ongoing flight tests involve a proof-of-concept vehicle powered by a battery. In the event of being selected to manufacture an air vehicle for a forthcoming ANCILLARY phase, Sikorsky intends to develop a 300-pound hybrid-electric version capable of accommodating a 60-pound ISR (Intelligence, Surveillance, Reconnaissance) payload.

Northrop Grumman

Northrop Grumman Corporation has been chosen by the Defense Advanced Research Projects Agency (DARPA) to progress to the next design phase of its autonomous vertical takeoff and landing aircraft, under the AdvaNced airCraft Infrastructure-Less Launch And RecoverY (ANCILLARY) program.

DARPA's ANCILLARY Phase 1b award will allow Northrop Grumman 10 months to enhance modelling accuracy, conduct vital subsystem testing, and mitigate key technical risks. Building on its extensive experience in developing and integrating autonomous vertical takeoff and landing (VTOL) systems and highly efficient long-endurance aircraft, Northrop Grumman aims to advance its ANCILLARY air vehicle design for DARPA.
Moving a step closer to creating a flight demonstrator, in this phase, Northrop Grumman will spearhead a collaborative team, utilizing Leigh Aerosystems' VTOL unmanned aircraft system, in conjunction with Near Earth Autonomy, to achieve project objectives and deliver a cost-effective near-term capability to the warfighter community.

Northrop Grumman plans to apply its expertise in autonomous vertical lift aircraft to enhance the design and system technology for DARPA's ANCILLARY autonomous VTOL uncrewed aircraft system.

AeroVironment

AeroVironment (AV) was down-selected by the Defense Advanced Research Projects Agency (DARPA) for continued development of its X-Plane design for the agency’s AdvaNced airCraft Infrastructure-Less Launch And RecoverY (ANCILLARY) program. AV’s offering – Wildcat – is a Group 3 vertical take-off and landing (VTOL) uncrewed aircraft system (UAS) developed specifically to execute ship-based operations in challenging maritime environments.

“We have prioritized controllability to ensure Wildcat meets the ‘anytime, anywhere’ goal of DARPA’s ANCILLARY program,” said AV’s Vice President of MacCready Works Chris Fisher. “Wildcat leans on autonomy to reduce operational burdens while enabling safe, infrastructure-less launch and recovery in challenging conditions from a range of Navy ships.”

Wildcat leverages AV’s SPOTR-Edge machine learning-enabled computer vision to enhance mission effectiveness. This capability builds on operational learnings AV has gained as a leader in the Group 1 to 3 UAS space with millions of operational flight hours on its Raven®, Puma™ AE, and JUMP® 20 uncrewed systems. Griffon Aerospace

Equipped with four motors for vertical takeoff and landing (VTOL) and an additional motor for forward flight, the RedWing can accommodate payloads of up to 5.5 kg.

Griffon Aerospace, founded in 1995 by Larry French, is based in Madison, Alabama, and specializes in the manufacture of unmanned aircraft systems (UAS), including UAVs and aerial targets. The company also produces ground support equipment. Griffon Aerospace has delivered over 6,000 unmanned air vehicles, maintaining a production rate exceeding 100 aircraft per month. The company's offerings extend to aircraft design and analysis, avionics and payload integration, and comprehensive testing services.

The Valiant features VTOL capabilities suitable for various environments. Additionally, Griffon has participated in the U.S. Army's Future Tactical Unmanned Aircraft System (FTUAS) program, with their designs selected for important development phases.

Griffon Aerospace
Griffon’s Valiant will have four propellers driven by electric tilting motors powered by a yet undisclosed hybrid power source. The carbon-fibre structure will be carried aloft by “one long thin main wing and a V-tail. Landings can take place on the craft’s belly or a landing frame.

The Valiant will have distributed electric propulsion, swappable payloads that offer a full range of ISR (intelligence, surveillance, target acquisition, and reconnaissance) missions, and the ability to take off and land on ships’ decks or ground-based small, unimproved landing sites.

Karem Aircraft

Karem’s Bluebird is, “A contrarotating, coaxial Optimum Speed Tilt Rotor (OSTR) aircraft. With a high wing and inverted V-tail, the carbon composite airframe houses a 40-hp heavy-fuel propulsion system. Excellent manoeuvrability required for shipboard operation is achieved using the rigid rotors’ powerful control capacity.”

Bluebird will probably incorporate Near Earth Autonomy’s state-of-the-art autonomy system providing operator-free takeoff and landing from Naval shipping and austere sites.
According to Karem, “The variable rotor RPM OSTR provides unmatched rotorcraft efficiency and offers a step change in VTOL performance.”

Method Aeronautics

The firm designed, built and flew the Vanilla Aircraft VA001, a 36-foot wingspan, 600-pound, machine that set several endurance records in. Method’s entry will doubtless stress efficient aerodynamics.
Vanilla has set several records including an October 2, 2021, flight lasting eight days and 50 minutes. Flying from Edwards AFB in California and covering 10,600 nautical miles (19,600 kilometres) in circuits, this was an internal combustion engine-powered UAV record ratified by the FAI. Only the Rutan Voyager has flown longer unrefueled.

Final thoughts

Steve Kominda, DARPA program manager for ANCILLARY, hopes for increased, “Uncrewed aerial system (UAS) capabilities by a factor of three over the current state-of-the-art flying today, Our performers are searching for innovative ways to increase payload weight and range/endurance of small, ship-launched UAS through novel configurations, propulsion, and controls while also removing the need for special infrastructure.” 

All six aircraft stem from experience with unpiloted systems and a high degree of autonomy.