The US Defense Advanced Research Projects Agency (DARPA) has selected two teams to develop designs for the agency’s Liberty Lifter seaplane wing-in-ground effect full-scale demonstrator.

The first team is General Atomics Aeronautical Systems (GA-ASI) working with Maritime Applied Physics Corporation (MAPC) and the second team is Boeing’s subsidiary Aurora Flight Sciences working with Gibbs & Cox and ReconCraft.

Work is being performed under Phase-1 of DARPA’s Liberty Lifter X-Plane programme that aims to design and develop a cost-effective, long-range X-Plane that can floating, flying and operate to undertake various seaborne strategic and tactical heavy-lift missions.

The GA-ASI and MAPC team has proposed a twin-hull and mid-wing design, with twelve turboshaft engines to offer distributed propulsion. It is expected to provide both seakeeping capabilities and on-water stability.

Aurora’s team has offered ‘a point-of-departure design’, which according to DARPA, resembles more to a conventional flying boat. It includes single-hull, high-wing and eight turboprops to deliver primary propulsion.

Under the Phase-1 contract, the two teams will work in close coordination with DARPA and other Department of Defense’s stakeholders to further hone their proposed designs, primarily focusing on addressing the operational concepts and requirements.

This will be an 18-month-long phase, with initial six months spared for conceptual design work and nine months maturation of design to finally progress to preliminary design review stage.

The remaining three-month time will be used for manufacturing and test/demonstration planning reviews.

DARPA Liberty Lifter programme manager Christopher Kent said: “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.”

The next phase, expected to commence by mid-2024, will involve detailed design, manufacturing and demonstration of full-scale Liberty Lifter X-Plane.