AirBear

https://www.cnn.com/travel/article/a...ane/index.html

Why this space age airplane could change flying forever

They're planning on 2000NM range 120-200 seat jets using hydrogen powered engines. Could be in service by 2035.

TransWorld

I wonder if they will be with smoke and mirrors? Or battery powered?

rickair7777

Normal jet engines powered by hydrogen would work fine.

The challenges (off the top of my head)...

1. H2 has VERY good specific energy (over twice that of Jet A), so it's light-weight. But if you use liquid H2, the energy density is about FOUR times that of Jet A... so you'd need a LOT more tank volume. While the fuel itself is much lighter, the weight and form drag of the extra tank volume will cost you. I assume airbus has done the math and come up with a plan... that blended wing-body thing would have a lot of internal volume.

2. Liquid H2 is difficult and dangerous to handle. Jet A is not explosive if spilled, liquid H2 is... very. It's also cryogenic, so everything in the storage and handling system will need to be "special" ($$$$$$$$$). Apollo used kerosene instead for these reasons, but space shuttle used liquid H2. The Saturn-V had a better safety record. Rampers gonna need a pay raise...

3. Compressed H2 would require very strong (ie heavy) tanks, and the volume would be impractical at any reasonable pressure (about twice the volume of liquid H2, eight times that of Jet A).

4. Lastly, there's some scientific concern that dumping a lot of water vapor into the upper atmosphere would have it's own greenhouse effect... and burning H2 has only one combustion product. Not sure what airbus is thinking with regards to that, maybe they just consider the last ditch excuse of the eco-freaks to justify "airplanes bad, your socialist masters should make you stay home".

Also you make H2 by splitting water molecules with electricity, so you'd need your grid power to be green, or you're just moving the carbon emissions from the sky to ground (maybe that's actually better for the climate issues?). The good news though is that you might not have to transport H2 to the airport... you can probably make it on-site with tap water and grid power (lots of both). And you get more free O2 than you could ever use too.

Beech Dude

As long as there are billions of barrels of crude coming out of the ground, this is not going to happen. Too much cost to change infrastructure and operations for the same exact result of airplanes taking people from A to B.

pangolin

If an efficient high bypass ELECTRIC turbine is created the h2 could be fuel cells to generate electricity rather than straight burning if.

UAL T38 Phlyer

McDonnell-Douglas did a feasibility study in the early 80s using a DC-10.

Every thing Rickair said. Plus: Cryogenic fuels have to be in strong spherical tanks.

You can’t put them in the wings and get any workable capacity. So, their study had two big tanks in the fuselage.

Result: could carry about 80 people SFO to DEN.

Impractical. A flying wing might work, but others have discussed before how uncomfortable or dangerous a ride in a big wing could be for passengers far from the roll-axis of the plane.

rickair7777

Probably doesn't make make engineering sense. Same energy, plus efficiency losses in power controllers, transmission and the motor.

Plus the weight of the extra hardware, somewhat offset since you could probably make a motor a bit lighter than a turbojet.

Fuel cells are probably better for smaller, slower planes which can get the benefit of things like DEP. Due to speed and power requirements, airliners will still probably need big fans.

123494

The bigger question is, will it have two pilots or are they going to try and push single-pilot?

rickair7777

If anything, climate compliance efforts will absorb resources and delay any further reductions in flight crew complement.

Autonomy is nice-to-have (for management), but they can still make money without it. And it's hard to have a serious conversation about 121 autonomy with hundreds of jets grounded over MCAS.

Environmental compliance (carbon but also noise and other emissions) is very much a "must have" in the very near future.

TransWorld

I agree with you, Rick. For these and more reasons, like smoke and mirrors. Sounds wonderful in a speech on campus or a talking head. But just does not look practical in reality.