The US Defense Advanced Research Projects Agency (DARPA) has selected teams led by General Atomics and Aurora Flight Sciences to develop designs for its Liberty Lifter seaplane.
General Atomics will be working with Maritime Applied Physics Corporation, and Aurora Flight Sciences with Gibbs & Cox and ReconCraft to develop full-scale demonstrators of the wing-in-ground effect aircraft.
The Liberty Lifter program aims to demonstrate a viable “ekranoplan” that could provide a “leap-ahead” in operational capability by designing, building, floating, and flying a long-range, low-cost X-Plane capable of seaborne strategic and tactical heavy lift.
The demonstrator will be a large flying boat similar in size and capacity to the C-17 Globemaster III transport aircraft. Goals include takeoff and land in Sea State 4, sustained on-water operation up to Sea State 5, and extended flight close to the water in ground effect with the capability to fly out of ground effect at altitudes up to 10,000 feet above sea level.
“We are excited to kick off this program and looking forward to working closely with both performer teams as they mature their point-of-departure design concepts through Phase 1,” said DARPA Liberty Lifter Program Manager Christopher Kent. “The two teams have taken distinctly different design approaches that will enable us to explore a relatively large design space during Phase 1.”
The General Atomics team has selected a twin-hull, mid-wing design to optimize on-water stability and seakeeping. It employs distributed propulsion using twelve turboshaft engines.
Aurora Flight Sciences point-of-departure design more closely resembles a traditional flying boat, with a single hull, high wing and eight turboprops for primary propulsion.
It is worth noting that Aurora is already working a DARPA project as prime contractor, where it is designing an X-plane that will fly without traditional moving flight controls on the exterior of the wings and tail.
During Phase 1, DARPA will work with both performer teams and Department of Defense stakeholders to refine the Liberty Lifter designs with particular attention to operational needs and operating concepts. The Phase 1 contract awards are for an 18-month period of performance with six months of conceptual design work and nine months of design maturation culminating in a preliminary design review. There will be an additional three months for manufacturing planning and test/demonstration planning reviews.
As scheduled, Phase 1 will transition into Phase 2 in mid-2024 with continued detailed design, manufacturing, and demonstration of a full-scale Liberty Lifter X-Plane. DARPA anticipates teaming with one or more partners for those activities and further development of the Liberty Lifter concept into an operational vehicle.