Aurora Flight Sciences has updated the design of its Liberty Lifter seaborne military heavy-lift transport – a highly efficient X-plane the company is developing for DARPA that achieves bulk lift by using wing-in-ground effect.
Since 2022, DARPA has been developing the Liberty Lifter, which is a project to develop a relatively inexpensive seaplane that has the cargo volume of a C-17 Globemaster III transport aircraft, yet can carry 100 tons of cargo. In addition, it is supposed to have a ferry range of 6,500 nm (7,500 miles, 12,000 km).
Aurora's candidate is in preliminary design Phase 1B of its development cycle, which places special emphasis on risk reduction in the steps for designing, building, launching, and flying the completed X-plane using low-cost manufacturing methods.
This involves Aurora teams building full-scale components, including part of the fuselage, using novel materials and then testing them before assembly. In addition, the company has built test models for water tests in a tow tank at Virginia Tech and is working on sensors for detecting and predicting surface waves.
One particular challenge is dealing with rough seas because the Liberty Lifter flies using the wing-in-ground effect where the aircraft flies low and gains additional lift by exploiting the air trapped between the wings and the surface of the sea. This is great in calm conditions, but when things get rough, the aircraft needs to be able to compensate to fly safely.
The latest changes to the prop-driven Liberty Lifter include swapping out the t-tail for a pi-tail. Essentially, this means that the stabilizers are held up by a fork-shaped rudder instead of a solid one. According to the company, this allows an aft cargo door while making the airframe more structurally efficient. Another innovation is to move the floats from the side-sponsons on the hull to the tips of the wings for better performance while keeping down costs.
Phase 1B is scheduled for completion in the near future, and the first flight for the Liberty Lifter is expected to take place in 2028.
Source: Aurora Flight Sciences
That’s some awe-inspiring confidence for a still in rendering design. And it will use “novel materials.” Like wood, a la the Hughes Spruce goose?
Hopefully the company has hired some Soviet era engineering consultants to verofy whether their failures were primarily technology or economic system-related.
And these are needed as combat ships, not just cargo that can get to place fast then sit and wait until needed deploying drones, missiles as needed then leave.
@clay, you're incorrect. Ground effect is proportional to the span of the wing. The longer the span, the higher an aircraft can fly while remaining in ground effect.
The rest of you armchair engineers are funny. Aurora has actually flown a number of manned and unmanned aircraft. I suspect their engineers probably know what they're doing. It's easy to sit back and second-guess companies like Boeing, but I seriously doubt any of you have actually designed or built a flight-qualified aircraft. It's one thing to wonder about design decisions. Quite another to present yourself as smarter than professional aerospace engineers.
Ground effect planes have been a novelty item due to lack of need and stability issues in rough weather. Hopefully the stability issues can be overcome with the faster response times with electric propulsion and electronics.
And now there is a need for this type of aircraft. Difficult to detect with radar since it hugs the water, but as fast as regular aircraft. It's also impervious to torpedoes and water based suicide drones.
In a sense, this is not an aircraft. It's a very fast boat.