DARPA reveals a new heavy-lift seaplane concept that can sense large waves

The Defense Advanced Research Projects Agency (DARPA) wants to build a new revolutionary seaplane that is capable of heavy lifting and will provide the U.S. military with strategic advantages as it expands its cargo airlift capabilities, an agency press release said.

Earlier this year, China announced that it was testing the AG600, an amphibious cargo aircraft, the size of a Boeing 737, as part of its larger plant to strengthen its presence in the South China Sea. When functional, the AG600 will be the world's largest amphibious aircraft with capabilities to transport personnel and cargo at over 300 miles (~500 km) an hour.

While DARPA's press release did not explicitly state its new plane, Liberty Lifter, was aimed at threats in the South China Sea, the agency did mention that it was looking for "new capabilities during extended maritime operations."

Seeking improvements to current heavy lifts

The U.S. military's ability to move cargo and personnel is quite efficient. DARPA, however, states that this ability at sea is vulnerable to threats and requires functional ports, which leads to transit delays. While traditional airlifts at relatively faster, their ability to support maritime operations is limited and is further constrained by the requirement of long runways or payload limits. 

DARPA is, therefore, looking at developing aircraft that can fly with "wing-in-ground-effect," which are runway-independent planes. DARPA's vision of the aircraft includes the ability to take off/land in the water with heavy loads in a fast and flexible way.

DARPA cites the example of the Soviet-era ekranoplans, which worked with the same principle but were restricted to calmer waters. Under the Liberty Lifter program, DARPA aims to build aircraft that can tread turbulent waters too. 

Challenges to Heavy Lifting at Sea

Turbulent water at sea is clearly the biggest hurdle when lifting at sea. DARPA's Liberty Lifter program, therefore, wants to incorporate advanced sensors and controls that will help the aircraft avoid large waves as well as handle the aero as well as hydrodynamic interactions that will develop as the craft attempts take-off and landing maneuvers.

The aircraft design will also aim at creating high-lift abilities at low speeds to reduce the impact of turbulent waves and even include solutions to absorb wave forces, the press release said. Since operations using these aircraft will likely take place in highly congested environments, DARPA also wants to incorporate anti-collision measures into the aircraft design. 

As part of its objective to use this plane for extended maritime operations, DARPA wants the aircraft design to allow extended operations at sea without the need for land-based maintenance activities. 

According to the press release, DARPA isn't looking for a revolutionary new material or design to build this plane. Rather, it wants the design to facilitate easy fabrication with materials that are cheaper to procure than those used in traditional aircraft manufacturing and preferably in large quantities. 

It does appear that the plane is being designed for rapid assembly and deployment at locations far-off from the U.S. mainland. The program, however, is still in its early stages, and it might be years before we see the aircraft take flight.