Hydrogen Powered Regional Aircraft?
 

Found this tidbit interesting:

https://www.dlr.de/content/en/articl...t-funding.html

Just food for thought, a CRJ 700/900 generator output is 115VAC @ 40KVA (115 x 40,000 = 4,600,000) = 4.6 megawatts.

but hey, turbo-props are coming back!

Been a while since I did electrical math, but if the gens in a CRJ are 3 phase, that 40kva would equate to about 200 amps each. A bit less than that for single phase. Puts it around 18,000-23,000 watts per gen. This is just spit balling a generic power factor into it.

kva = kilovoltamps. 40kva at 115 volts is 350 amps. Voltage times kva squares the voltage

https://www.coresite.com/blog/faq-what-is-kva

40kva would imply roughly 40kw

A Watt is a VA, a Kilowatt is a KVA. They are 40 KVA which is 40 Kilowatts.

This s a rating of their max power output.

It’s just funny to me that someone, for a short amount of time before being corrected, thought the CRJ was the most efficient power generator in the world. . .

Well it is a Canadian Jet, so using rough numbers. If at 115v and 40Kva, how many “sorrys” per “Eh” is that?

Yes, there are no mega-watt class electrical power sources on a CRJ, lol.

The engines themselves would have a power output in the MW range (if you convert thrust to MW).

H2 has some appealing attributes for use in green aircraft.

The problems are the production, storage, and handling. H2 is either an highly explosive pressurized gas, or a highly explosive cryogenic liquid. It is also much less dense than Jet A

On the ground that would require all-new infrastructure. Since H2 is produced from water and electricity it's inherent "greenness" is dependent on the source of the grid power used to make it. You might be able to produce it onsite at the airport, if you had enough space available.

On the plane, you'd need a clean-sheet design to accommodate enough fuel tanks to hold larger quantities of the less-dense H2. H2 is lighter than Jet A (higher specific energy), but that would probably be offset by the weight of larger tanks, the weight of structure to hold the larger tanks, and the associated form drag of said structure. Might be able to mitigate that with a radical fuselage design, like a flying wing (which has it's own logistics issues).

I think it more likely future regional jets will be electric powered. That merely requires a slight technological breakthrough in extension cord technology...

While my dreams of becoming a Electrical Engineer are shot. I wanted to put forth the notion that maybe we’re barking up the wrong tree. Sure H2 has 3 times the energy on a per mass (weight) unit. However it’s the volume that’s the issue. So in the mean time how about developing hybrid aircraft, at least until the H2 storage and production method & technology mature.

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.

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

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

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.

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

LOL, Gigawatts I tell you!!

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