Airbus Zero Emissions Concept
 

Airbus unveils their Zeroemission Aircraft Concept.

https://www.airbus.com/newsroom/pres...-aircraft.html


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The path between computer rendition and tarmac is very long.

"Support from governments will be key..." Which government has any money left?

What are the big picture challenges with using Hydrogen specifically within the airframe?

I'm assuming storage volume, insulation, leak proofing are big ones before you even get to a power plant? Are we talking pressurised gas or cryogenics?

Are they planning to burn it in a gas turbine or some kind of fuel cell and electric propulsion?

The whole area is fascinating but a lot of basic hurdles to overcome along the way.

That turbofan looks very nose heavy.

Bit of both - combusting it for propulsion, fuel cells to power electric consumers in the aircraft.

You'll note the rearmost passenger doors are placed quite well forward, indicating the aft pressure bulkhead is also quite a bit further up than we're used to in today's designs.
With the hydrogen storage systems being placed aft of the bulkhead, you need quite a bit of fuselage forward of the wing to balance things out again.

If you look at the mid range jet design, the wings also seen placed pretty far backwards - same reasons as you have significant weight sitting in the back

But whenever the hydrogen is spent and the tank empty don't you end up with a steep descent? Green MCAS so to say.

We can only hope that today Airbus FMA (failure mode analysis) is up to expectations ...

Would the weight of burnt H2 be an issue? Present designs are well tolerant for using up the fossil load. Quite significant sometimes.

My assumption is containers for liquified gas introduce the new angle, but those would stay for the full duration of the flight.

H2 has 3 times the energy density of fossil fuels PER KILO. So ideally, the fuel mass should only be a third for the same stored energy, ignoring all other factors (storage, efficiency ...)

......(storage, efficiency....) and pressure and cryogenics. A transportable load of 3500 kg (equivalent to ca 10000 kg kerosine) would require 200 bar. A flying bomb in my humble opinion.

Engines, passenger cabin, cargo and cockpit/avionics and some long fuselage section look like being deliberately placed ahead of the center of gravity while the tail looks very short. What heavy stuff is hidden inside the tail section if it's not the fuel itself? The pressure tanks? The insulation? Fuel cell? It must be quite heavy.

But the volume is significantly higher, so trading off some of that gain against increase sized tanks, larger structures, more drag &c. I find the whole thing absolutely fascinating and if 2050 really is the target look forward to flying some of these things before I retire.

What sort of issues are hiding in there? Is fuel gauging with cryogenics (if that’s the route they take) much harder? I almost wish I were clever enough/made the right career choices to be involved in development.

I am wondering why existing models couldn't be modified to run on hydrogen ? Obviously, new engines would be needed, and fuel tanks would need to be pressurized and able to withstand that pressure, but ?

Google 'roland berger Hydrogen: A future fuel for aviation?' , it's short and a good starter to the topic.

The target is 2035, 15 years from now. Given the timescales in aviation and the problems to solve : tomorrow. (as Airbus said in their presentation)

Thanks fruitflyer for posting a link to the article. To be clear, my question had to do with the usage of hydrogen combustion, not fuel cells.

The main problem seems to be that storing enough hydrogen in a practical manner in liquid form requires cooling, down to -253 deg Celcius, and just the cooling may consume up to 45% of the fuel itself.

Its been suggested that the oil companies are keen on hydrogen (you separate the it from the carbon in oil) but realistically it will come from electrolysis. The trouble is that we don't have enough renewable fuel for the existing grid and would need far more for electric cars and huge electrolysis plants. That's a lot of wind farms and photoelectric cells. Its interesting that going back to my childhood (half a century ago) the future was nuclear power, the power being used to create hydrogen which would be burnt in aircraft. Back then the problem was seen as lack of oil and no one had thought of global warming, but it was still felt that new sources of energy would be required. We know that technology advances, the question is how fast and crucially in which areas. Look at an episode of Thunderbirds (mid 60s). The (actually very perceptive) writers missed the rise in computers, algorithms, internet, mobile telephony for all (nor just a few selected International Rescue agents), etc but seemed to think that we would have rather more nuclear powered devices masses of supersonic commercial aircraft and so on. If we look back to today in thirty or fifty years how accurate will our predictions to the future look?

Its amazing how much technology come about because of the space race in the 60s. The Saturn V used cryogenic storage - for a few hours, it couldn't be used later in the mission and if launches were delayed the fuel was allowed to bubble off, rather wastefully - but maybe it was assumed that cryogenic storage would advance. If we announced the equivilant to the Apollo programme for sustainable fuels where would we get?

My view is that the future is biofuel derived from algae (seaweed) which will cost a lot more than jet fuel does today but partially offset by more efficient aircraft making aviation affordable. Oil refineries may disappear to be replaced by large algae processing plants, but the actual fuel distribution network will be similar to today's. I may of course be wrong as to which technology works which is why I fully support the development of hydrogen and electric powered aircraft - and any other promising new technology that comes along. Lets hope that one of them achieves a breakthrough.