rickair7777

You can make a decent case for hybrid. Idea being to optimize the turbine engine(s) for cruise performance... it/they can be smaller and lighter. The battery then makes up the additional power required for T/O, G/A, and climb (and charges on descent or on the ground).

Current turbofan engines are sized for takeoff at MGTOW... with the other engine failed. That's a lot of motor that you almost never need, but still have to haul it around the skies.

The devil of course is in the details... by the time you add the weight of the batteries, generator, electric motor, controllers and power cables you've eaten up a lot of the weight savings. There are various concepts to chip away at that problem, but right now it's hard to make the case.

Also one thing most people don't think about... as we burn jet fuel, the plane gets lighter and that has a significant positive impact on overall flight efficiency (especially on longer flights). But batteries never get lighter.

ZeroTT

If there is any use case for burning hydrogen... it’s airplanes. Converting the US 121 fleet to hydrogen would require building 500 hydrogen stations. They are probably more gas stations than that in Rhode Island

rswitz

Work work work gens work work work approaches work work work megawatts

rickair7777

Those would be rather large gas stations. Look at the fuel tanks at any big airport... you'd need almost four times that volume for equivalent liquid H2 (7-8 times for pressurized H2).

For clarity, "converting" the fleet would mean scrapping all of the existing aircraft and building all-new ones designed for H2. You *might* be able to repurpose existing engines, but I'm sure you'd have to modify the combustion chambers.

Also... there is some concern that jet airplanes injecting moisture into the (normally dry) stratosphere creates a greenhouse effect of it's own. Water is a byproduct of all IC engine operation... it's the ONLY byproduct of H2 combustion. SAF might actually be better for greenhouse purposes than H2.

ZeroTT

Sure it’s a big infrastructure project. But it’s vastly simpler than using hydrogen for cars or trucks. Even if every big airport has a plant offsite and it’s own two mile pipeline.

For a 50 year project, it is quite technically feasible

and used a380’s are probably viable for conversion

trip

LOL, Gigawatts I tell you!!

arbalist1

I heard of this guy that got 1.21 gigawatts out of a DeLorean.