RPI Doctoral Student Develops New Graphene Material with 14% Wt. Hydrogen Storage Capacity
Microchannel GTL Demonstration Plant Will Produce 5-10 bpd; Targeted for Offshore Platforms

Boeing Begins Building Phantom Eye Hydrogen-Powered HALE Demonstrator

The Boeing Company has begun to build Phantom Eye—its first unmanned, liquid-hydrogen powered, high-altitude long-endurance (HALE) demonstrator aircraft.

The essence of Phantom Eye is its propulsion system. After five years of technology development, we are now deploying rapid prototyping to bring together an unmanned aerial vehicle [UAV] with a breakthrough liquid-hydrogen propulsion system that will be ready to fly early next year.

—Darryl Davis, Boeing Phantom Works president

The jig load assembly, model of a liquid-hydrogen engine and fuselage skins for Boeing’s Phantom Eye demonstrator in St. Louis are part of the high altitude long endurance aircraft being assembled by teams in Boeing’s Phantom Works division. Other work on Phantom Eye is being done in Irvine and Huntington Beach, Calif., and in Seattle. Boeing photo. Click to enlarge.

In 2007, Boeing announced that, using a Ford Motor Company-developed hydrogen engine, it had successfully tested the hydrogen propulsion system of its High Altitude Long Endurance (HALE) unmanned aircraft. During the test, the engine ran for nearly four days in a controlled chamber at Aurora Flight Sciences in Manassas, Va., including a total of three days that simulated conditions at 65,000 feet. The propulsion system included a multi-stage turbocharged internal combustion engine and its associated subsystems. The Ford engine earned better than expected fuel economy while demonstrating complete airflow and torque control across the engine's operating range.

Phantom Eye’s entire propulsion system—including the engine, turbochargers and engine control system—successfully completed an 80-hour test in an altitude chamber on 1 March, clearing the way for the propulsion system and UAV to be assembled.

The twin-engine Phantom Eye demonstrator will have a 150-foot wingspan and be capable of flying for more than four days at altitudes up to 65,000 feet while carrying a payload of up to 450 pounds. Phantom Eye is designed to maintain a persistent presence in the stratosphere over a specific area, while performing missions that could include intelligence, reconnaissance, surveillance and communication.

Boeing also is developing a larger HALE that will stay aloft for more than 10 days and carry payloads of more than 2,000 pounds, and building “Phantom Ray,” a fighter-sized UAV that will be a flying test bed for advanced technologies.

We believe Phantom Eye and Phantom Ray represent two areas where the unmanned aerial vehicle market is heading, and rapid prototyping is the key to getting us there. These innovative demonstrators reduce technology risks and set the stage for meeting both military and commercial customers’ future needs.

—Dave Koopersmith, Advanced Boeing Military Aircraft vice president

Phantom Eye evolved from Boeing’s earlier success with the piston-powered Condor that set several records for altitude and endurance in the late 1980s. Boeing, as the Phantom Eye system designer, is working closely with Ball Aerospace, Aurora Flight Sciences, Ford Motor Co. and MAHLE Powertrain to develop the demonstrator. Phantom Ray evolved from the X-45C program. It is scheduled to make its first flight in December.


Account Deleted

When Boeing succeeds in making the 10 day non-stop UAV running on liquid hydrogen with a one ton bumming capacity the US will be able to survey and hit any target on the planet from a US based airbase with these planes. Assuming it can fly 350 km/h means it can fly 84000 kilometers (24*10*350) non-stop without refueling. That is twice around the earth at equator. That will change everything about how the US deploys its air forces. In principal carriers will no longer be needed.

Air supremacy enhances the fighting power of a local force by many times. This means that the US could multiply the fighting capacity of a native force by multiple times without deploying any people outside of mainland USD. That could be very useful in several parts of the world. It costs incredibly much to deploy soldiers far from the USA mainland and it always ends with these soldiers looking like evil occupiers that are hated by the locals. It is a much better idea to cooperate with native forces multiplying their fighting capacity through long-distance UAV air-supremacy.


Running a reconnaissance aircraft has got almost nothing to do with fighter and bomber planes.
They don't have the need for the high thrust and very powerful engines.
Manned planes may indeed be under threat - you can bank harder than a human body can stand in a UAV - but they will need aircraft carriers to fly from.

Roger Pham

Why LH2-piston engine, instead of petroleum-burning engine that allows more efficient energy storage?

Was Boeing contemplating the possibility of using solar energy to produce H2 to power the engine, and then recovering the water from the engine exhaust for electrolysis?

If so, then, the airplane will have considerable longer range than any fossil-fuel-burning planes known. It may have indefinite range, limited only by the durability of the engine or other systems, if excess H2 produced during the day can be stored on board for night time use. Or, the airplane can glide down at night to a lower altitude, and climb up again to high altitude during the day, if insufficient quantity of H2 can be stored.

At stratopheric altitudes, the sun will always shine during the day everyday, such that solar energy will be very reliable.

Account Deleted

They are using liquid hydrogen because this is the best fuel available with regard to UAVs. The gravimetric energy density of liquid hydrogen is 143 MJ/kg versus only 42.8MJ/kg for kerosene jet fuel. Liquid hydrogen is not used for manned aviation because of its low volumetric energy density which is 10.1MJ/L versus 33MJ/L for jet fuel. The liquid hydrogen fuel tank needs to be so large that it is getting really difficult to add a passenger cabin for humans.

Also I don’t believe for one minute that they use a combustion engine even though they write so. This is a military project so they are almost obliged to lie about it. My bet is that they use a PEM fuel cell in combination with cryogenic power electronics and electric motors. The PEM fuel cell will be 60% efficient and the electric system will be 100% efficient because it can use superconductive components cooled by the liquid hydrogen. This is much more efficient than any combustion engine can ever be.

I think you are right with regard to using solar cells on the wings to harvest sun energy in-flight which is strong at this high altitude. The plane with a 450 pound payload has a 150 foot wingspan. This is a big plane and the one with a 2000 pound payload will be even bigger. I guess 220 feet or like a Boeing 747. This is a lot of solar panels but not nearly enough to keep it airborne with a 2000 pound payload and not giving it enough speed to be very useful for military applications. It needs to fly minimum 150 mph to be useful. Solar panel wings could nevertheless contribute perhaps 10% to 20% in longer range and travel time.

This UAV is way too big to take off from a carrier as you can see. Also even though it is certainly not a dogfighter and never will be it can still be an effective bomber and fighter. It can drop precision bombs from high altitude and it can fire long range (150 miles) air to air missiles to shoot down other planes. It can also carry jamming and magnesium bombs to avoid missiles from other planes. If these planes fly in large swarms they can have enough firepower to prevent conventional planes from getting at shooting range. But they will be easy targets for conventional fighters if they run out of missiles.

Nevertheless, a 2000 pounds payload, 10 days non-stop UAV with minimum 150 mph speed will completely change the way the US will do wars in the future. It is badly needed so I hope they can get it operational ASAP. They should fly it even if it is not completely tested as it is only a UAV.



"If these planes fly in large swarms they can have enough firepower to prevent conventional planes from getting at shooting range. But they will be easy targets for conventional fighters if they run out of missiles."

If the aircraft flies under 30k ft it is in range of stinger attack. And surface to air attack up to max altitude. If they go PEM cryo - there is EMP vulnerability.

Logistically, it is clearly an asset.

Henry Gibson

Fuel Cells are too expensive for even hydrogen fueled vehicles.

The correct choice of fuel is almost always diesel or JP-X . Diesel piston engines can be made very efficient. A combination diesel-steam engine can be made as efficient as a fuel cell at much less cost.

Modern materials make hydrogen supported dirigible blimps useful and not much fuel is needed to keep them aloft. They also could be solar powered to stay up forever. ..HG..

Roger Pham


At 150-ft wing span with a 15:1 aspect ratio, the plane will have 1500 sq.ft of wing area. This is equivalent to 150 square meters. At 1kW of insolation and at 20% solar PV panel efficiency, 30kW of power can be generated during the day time. Given the very high efficiency of the plane, this much power is sufficient for maintaining altitude, or even to climb, especially in the presence of thermal rising air current.

But, you are right, since this power is marginal, turning this solar energy to H2 and then using to power a FC won't be sufficient to power the plane. The best way is to climb during the day on solar power and also taking advantage of rising thermal currents, while charging the battery with some excess power, and gliding down at night while using some battery power to avoid getting too low, would be best way to remain aloft indefinitely! It is possible if the plane is made light enough and big enough.


This thing has more offensive military potential than a weather balloon - but not much.

The comments to this entry are closed.