Hydrogen fuel?
 

I didn’t think it was this close to reality.

https://hydrogen.aero/product/

Interesting though, hey?

Just clicked the 'like' button. No paywall, no cookies request, and a good lean article. Way to go.

One or two fallacies in that article.
Not quite sure how that transatlantic A321 stretch is going to rotate without major changes to the landing gear.
How do the economics of an A321 payload workout on an aircraft almost as big and heavy as a B757-300?

Did you notice how much of the fuselage has to be devoted to hydrogen storage? You know, the area where today paying passengers sit?
I also wonder how the FAA/EASA are going to feel about storing huge amounts of highly pressurized hydrogen in the fuselage along with the paying passengers, given that the rupture of one of those hydrogen tanks would likely be catastrophic.

Salute!

The biggest problem is the "green" production of the hydrogen.

Can't be electrolysis for awhile, as Europe/UK already having problems by shutting the nukes and trying to get windmills and PV farms to provide the volts/amps. The other common means for getting the H2 involves using evil greenhouse gases.

I also noted too many references directly or implied about the COP or other outfits trying to save the planet by reducing use of fossil fuels before reliable and plentiful and cheap "green" capabilities exist.

Gums sends...

Interesting concept. I assume the energy numbers work out but looking at the illustrations, having all the fuel stored in the fuselage a long way from the CG could be problematic as it burns off; yes, H2 has a higher energy density (Wh/Kg) than Jet A-1 but there is still going to be a significant mass of it. I can sort of see why they didn’t put it in the middle, like a conventionally fuelled aircraft, as it would split the passenger compartment in two, but you could engineer a corridor or such and have the tanks much closer to the CG...?

Great Idea, why has nobody thought of it before?
https://cimg5.ibsrv.net/gimg/pprune....833bb33a0d.png

Oh hang on.....

Indeed lots of problems looking for clever solutions. Interesting that some commuter outfit in the USA has signed for 12 x Dash 8 conversions. One assumes they’re looking for enough fuel capacity to cover 60 minute sectors, so say about 120 minutes of fuel on board.

If liquid H2 has a much higher density than JetA1 as they say, then one could argue that it requires less mass of fuel to go the same distance. Although there’s no mention of the total volume and mass that is required for its storage on board. I’m guessing JetA1 is still much “lighter” when you take all the supporting hardware for H2 into consideration. On the other hand, wings which don’t need to carry fuel can be made a whole lot lighter.

Many, many variables.

Nevertheless, I’m surprised that H2 as a fuel is actually so far advanced and looks like being practical.

I think the opposite is true.

if the all load is carried inside the wing, then bending stresses are reduced. If the load is carried in the fuselage, then the wing bending stresses are increased. Maximum zero fuel weight is due to wing bending loads. Fuel can then be carried in the wings up to max take off weight.

If all the fuel is carried in the fuselage, then the aircraft wing structure must be beefed up (extra weight) so the zero fuel weight can be increased up to max take off weight.

What Goldenrivett said - fuel in the wing requires less structural strength in the wing than fuel in the fuselage.
Also, liquid H2 is more energy dense that JetA in weight, but far less dense in volume so far more volume is needed (as in several times). The linked article suggests high pressure H2 storage - which is even less dense than liquid H2.

Yes, I understand relief bending moments.

The present wing has to be built to be strong enough to carry a full load of fuel when parked and also strong enough when loads are in the opposite sense - I.e. strong enough to provide the required lift when the wing is empty.

My thought was if the major load was only in one direction, I.e. lift, then lightweight composite wings could be built lighter. But, hey, I’m not a structures guy.. so always happy to be corrected.

It will be interesting to see how these 12 Dash 8s work out in the real world.

Neither a structures person, but seem to recall it's the wing root / wing box that gets heavy for the fuselage loads. Not the wing itself. Understanding what you mean by the possibilities of a completely dry wing, yet remember that on contemporary certification the allowed airborne load is 2,5g. That's where the hydro tanks come to play. Either in absolute measure of mass or as a displacement of payload from ZFW.