DARPA sets goals for Liberty Lifter heavy-lift seaplane

The US Defense Advanced Research Projects Agency (DARPA) has revealed ambitions to develop and flight test an experimental low cost, wing-in-ground effect-capable seaplane for long-range, low-cost seaborne strategic and tactical lift.

Named Liberty Lifter, the project envisages a hybrid boat/plane air vehicle able to operate efficiently in ground effect, sustain out of ground effect flight, and enable efficient theatre-wide transport of large payloads at speeds far exceeding existing sealift platforms.

A Broad Agency Announcement (BAA) was released by DARPA on 16 March. The agency's Tactical Technology Office plans to award up to two initial contracts for concept design studies as the first increment of a planned three-phase developmental cycle intended to culminate with a first ‘X-plane' flight at the end of fiscal year 2027.

Liberty Lifter was conceived to circumvent the constraints of traditional sealift that, while efficient in transporting large amounts of payload, is vulnerable to threats along extended lines of communication, subject long transit times, and requires functional ports. Conventional airlift is orders of magnitude faster, but is expensive and limited in its ability to support maritime operations. Additionally, aircraft require long prepared runways or suffer payload limitations typical for vertical take-off and landing aircraft.

DARPA's concept seeks to introduce a new heavy-lifter capable of fast, flexible strategic lift with large payload mass and volume. While primarily designed for efficient flight in-ground effect, so as to extend unrefuelled range, the air vehicle is also intended to be capable of sustained ‘up and away' flight at mid-altitudes.

The vehicle concept seeks to combine the versatility of a seaplane with best practices from commercial high-speed vessels to be capable of sustained surface operations, and DARPA is stressing a low-cost design and construction philosophy.