Saturday, February 11, 2023

DARPA Funded Two Wing in Ground Effect Transport Planes

Anything able to accomplish ground effect is merely a modest increase in airspeed from flying much higher.  Do you really save on fuel to cruise on the ground effect pad?

The big advantage is using water to land almost anywhere and possibly lowering ground speed will let you land on an airfield.  Ground speed flight should have you traveling at under two hundred knots.  Great for sea based transport by the way.

What is quite likely is that this monster can be hugely expanded where the carrying body is several times wider.  Then ground effect value really kicks in as it competes then against water borne traffic.  Imagine a five thousand ton craft able  to travel at two hundred knots over normal medium seas and obviously able to fly around high seas or away from.  You are certainly not fling this into a Typhoon.

recall five thousand tons used to be as big as it got back before container ships and bulk carriers.  such a craft would alxo be able to dock on a piece of flat land as well allowing easy offloading and loading.

The bottom line is not to compete with large aircraft at all.  Manufactured goods could pack fifty containers and then run by  sea from shanghai to LA or across the Arctic ice to Rotterdam in about one month. or a fraction of current haulage..

DARPA Funded Two Wing in Ground Effect Transport Planes

DARPA Funded Two Wing in Ground Effect Transport Planes
February 5, 2023 by Brian Wang

Two teams — General Atomics working with Maritime Applied Physics Corporation and Aurora Flight Sciences working with Gibbs & Cox and ReconCraft — will develop designs for DARPA’s Liberty Lifter Seaplane Wing-in-Ground Effect full-scale demonstrator. The Liberty Lifter program aims to demonstrate 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 planned Liberty Lifter 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.”

“Liberty Lifter will use low-cost manufacturing akin to ship fabrication in building a highly innovative seaplane capable of meeting DoD heavy lift requirements [100+ tons] that operates with runway and port independence.”

General Atomics was awarded $8 million cost-plus-fixed-fee contract award in support of DARPA’s Liberty Lifter program in November for the work, the company announced Wednesday. The contract could include options brining the value to $29 million. Aurora’s contract, which DARPA awarded Jan. 27, was for $5.7 million and could grow to more than $25 million if all options are exercised. Aurora, a Boeing subsidiary, was awarded $5.7 million on Jan. 27, with options that could grow the contract to $27 million.

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.

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 DoD Service and international partners for those activities and further development of the Liberty Lifter concept into an operational vehicle.

History of Wing in Ground Effect Planes

It was actually built and flown.

The Ekranoplan had wingspan of 37.6 m, length – 92 m, maximum take-off weight – 544 tons. It was the largest airplane until the Ukrainian An-225 was built. Ekranoplan was designed to fly at an altitude of 5-10 meters in order to utilize the ground effect.

The Boeing Pelican ULTRA (Ultra Large TRansport Aircraft) was a proposed ground effect fixed-wing aircraft under study by Boeing Phantom Works. Intended as a large-capacity transport craft for military or civilian use, it would have a wingspan of 500 feet (150 m), a cargo capacity of 1,400 tons (1,300 metric tonnes), and a range of about 10,000 nautical miles (18,000 km). Powered by four turboprop engines, its main mode would be to fly in ground effect 20–50 ft (6–15 m) over water, though it would also be capable of overland flight at an altitude as high as 20,000 ft (6,100 m) albeit with a decreased range of about 6,500 nautical miles (12,000 km). It would operate from conventional runways, with its weight distributed over 38 fuselage-mounted landing gears with 76 wheels. The Pelican was never built.

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