for comparison between battery and energy density:
typical lipo as used in a short flight endurance hobby quadcopter (5-7" prop size) is 155Wh/kg
the best lithium ion cylindrical cells are around 255Wh/kg right now. quite a bit more limited in instantaneous amperage draw per cell than high C rate lipo.
hydrogen fuel cell tank+PEM+piping+DC apparatus for large octocopters comes in somewhere around 1500Wh/kg
There's a south korean company that recently hovered a large octocopter with hydrogen power source for 10.5 hours. Same system with lithium ion battery power would be approximately a 1 hour endurance.
note that 1500Wh/kg is considerably less than the energy density of jet-a or diesel or ordinary 87/89 octane petrol, BUT, you have to account for 50% of it being lost to waste heat in an internal combustion engine, and the weight of the engine and drivetrain. or weight of jet turbine+generator vs hydrogen tank + fuel cell PEM apparatus.
255Wh/kg? That’s not true. About 300Wh/kg has been available for over a decade. The next Gen lithium metal anode and lithium sulfur batteries can do 400-500Wh/kg, up to 650Wh/kg in the lab.
I'm referring to li ion cylindrical cells in the 18650, 20700 and 21700 formats which are commercially available right now. Which I can buy online in 5 minutes with my visa card from a battery wholesaler.
If you can find me the pdf datasheet for one that's above that I'd love to see it!
And even better a vendor link.
Note I am also referring to something like the actual usable watt hours from a battery before you discharge it below "permanently damaged" state, in the range starting from 100% SOC standard full voltage and manufacturer's do-not-exceed floor voltage. Such as on the NCR18650GA.
I don't doubt there are specialty rare "ask us for a price" low volume 300Wh/kg in circulation if you have the right contacts.
> BUT, you have to account for 50% of it being lost to waste heat in an internal combustion engine
What's the efficiency of a battery-powered system in flight? E.g. disregarding ground charging and grid supply.
(edit) Wikipedia says ~95% for a generic electric motor and ~85% for a generic lithium-ion battery for a very rough estimate of about 80% efficiency in toto.
Also depends how you have many batteries paralleled and the amp draw per cell, for instance a single Sony vtc6 cell might be ok for 30A draw for short times but will heat up while doing it. And needs cooling/thermal dissipation solution. The lower amp draw per cell the less is lost to heat.
> But let's say you can climb the thing at 1000FPM and 100KIAS. That takes you an hour (covering roughly 250 nm?) to hit 65,000. If you spend an hour at cruise and then come down at 2000 fpm again covering 150nm ... you've just taken 2:30 block to go 900nm. What market does that make sense in? Might make a great autonomous cargo bird for Fedex.
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> People spending 5 million on an airplane do not care about $180 of fuel difference per flight, and also that is only at altitude. If the climb rate of that airplane is 1,000fpm, which seems optimistic, it would take nearly an hour to get up there. If you are going on a 2 or 3 hour leg, fuel burn could be the same or worse.
IMHO (almost layman), takoff catapult is the way to go for energy efficiency of aircraft. If you imagine a takeoff around 200KIAS, the conversion of cynetic energy in potential energy gives you a big part of the climb. The spared energy would increase the flight range.
Prototype can hold 6 passengers. The design can scale up to 19, but "the low-drag laminar flow model relies on a width-to-length ratio that'd be impractical in a bigger bird" so it won't work for airline use.
Was wondering about this - im just not that impressed about anyone making personal jets more efficient. Those things shouldn’t be in the sky in the first place.
19 passengers isn’t personal aviation. It comparable to passenger aircraft used in places like islands and elsewhere where demand isn’t enough for big jets and there’s no ground option.
Fundamentally, it could be nearly as cost efficient as large jets. The pilot wage is a small portion of the overall cost. A big reason big jets are big is because jet propulsion scales down poorly while electric scales down very well.
Fully agreed. Personal aviation is ludicrously inefficient and still often remains outside of meaningful regulation in key ways like using leaded fuels. Poisoning the globe and locales for one person’s convenience should always be questioned as a sign of inequality too far gone
- Commercial planes begin at about 50-60 seats, less are non-viable.
Normal commercial size - 100 seats.
For air-dynamics, 3 times capacity enlarge (from 6 to 18) typically possible, but more changes too much.
And 3 times capacity in avia measured non linear, but with famous square-cube rule, which mean, change size will increase mass as square, but capacity as cube, so to got 3x capacity, need 1.443 increase of size (1.442^3=3.0046853).
I don't believe regular planes to ever run on hydrogen and be commercially viable. Hydrogen is not very dense, even in liquid form (to be compared with the volume already taken by kerosene on a plane). And requires very strong -and thick- container walls.
However with dwindling fuel supplies, I'm pretty positive we'll see the return of glorious, massive blimps. Powered by a fraction of the hydrogen it uses to float in the air, savvy meteorology, and thin solar panels.
Not really, it's more likely to be stored at low temperature to avoid embrittlement. Liquid Hydrogen has an energy density of approximately 120 MJ/kg, almost three times more than diesel or gasoline. Even with the cryogenic storage and reheating equipment it has comparable power to weight ignoring electrical motor efficiency advantages. Comparable flight hours do take up 2-3x more volume than diesel (including pumps and fuel cells), but at larger sizes (e.g. 737 and larger) most commercial flight distances are limited by weight rather than volume.
A lot of things come down to scale. Small drones can run reasonable distances on LiPo, which scales very badly to larger vehicles.
Right. The strongest evidence is commercial planes will be exclusively hydrogen powered. Airbus is working on one right now https://www.airbus.com/en/innovation/zero-emission/hydrogen/... (I think 2035 is way too long - it needs to be done 10 years ago)
What more there will be hydrogen fuel plants onsite at the airports
Additionally you'll see hydrogen in similar large systems such as rail and earth moving equipment.
Honestly the only question I have in the large vehicle systems is cargo ships. There's plenty of space and benefit to large solar wings expanding the vessel surface area that can fold up when necessary
If you see the efficiency gains and cost reduction in commercial grade PV continue, it's going to be unit cost economically superior fairly soon.
Alternatively there could be some mystery device that can get a net energy gain by processing sea water to hydrogen fuel. This doesn't look physically impossible but I haven't heard of any serious efforts to do so yet and personally I'd need a lot of convincing to be assured it wouldn't just be doing a new flavor of ocean polluting
Can't the low density be taken advantage of, producing aircraft with blimp-ish characteristics? Not sure how practical that is...
And given how big % of fuel is needed for ascending to cruise height, I'd imagine you could have a decent % of the fuel in take-off tanks with thin walls, since those tanks only need to contain the fuel for less than 10 minutes anyway.
I could imagine future planes using hydrogen for take-off and batteries for cruising.
An amazing technology, optimizing the thing we need the least right now: rich people's private jets.
We need to fly as little as possible, not to incentivize it even more. 80% less fuel consumption? Expect people flying 5 times more, and feeling like they are doing a favor to the environment. Jevons Paradox.
If, indeed, this can be made to work with a zero emission hydrogen power source, why would we seek to limit that air travel the same way we might seek to limit fossil fuel based planes ?
Are you suggesting that air travel - of any kind - is negative?
Yes. The core concept of progressive views is 'pain and sacrifice'. It doesn't matter who but someone should always be making some personal sacrifices for the whole to be satisfied. Some times it is plastic straws by common people and some other times it is billionaires's hydrogen jets.
Hey we have this AMAZING tech (supposedly). But wait, we're not going to commercialize / actually produce it even though if true it'd print money.
Look we have this (other) AMAZING tech, we are going to combine these so that's why we aren't showing Amazing Tech #1.
And repeat.
---
Most get rich books / authors / etc - if they had a way to actually beat for the forex market etc they wouldn't be selling $50/books on how to do it. Same thing here. if they had a massively efficient plane (with a prop - also efficient) they'd actually deliver.
The claims made by Celera have always been aggressive - and I hope they’re real. Why add more claims? Why not just deliver on what they currently offer?
This seems like a red flag and possibly indicates shenanigans.
They've optimized for cabin volume and all their claims are weirdly crafted to take advantage of that design choice.
For passengers who expect a flight with 4 first class-type seats, their competition isn't a minivan with wings like the beechcraft bonanza, it's a learjet with half the seats removed.
Exactly what I thought. Laminar airfoils with max thickness far back do very well in the computer but they behave poorly. I would want to see proven that this plane is stable in all conditions.
Putting a hydrogen engine in it seems like a distraction.
Readit News
typical lipo as used in a short flight endurance hobby quadcopter (5-7" prop size) is 155Wh/kg
the best lithium ion cylindrical cells are around 255Wh/kg right now. quite a bit more limited in instantaneous amperage draw per cell than high C rate lipo.
hydrogen fuel cell tank+PEM+piping+DC apparatus for large octocopters comes in somewhere around 1500Wh/kg
There's a south korean company that recently hovered a large octocopter with hydrogen power source for 10.5 hours. Same system with lithium ion battery power would be approximately a 1 hour endurance.
note that 1500Wh/kg is considerably less than the energy density of jet-a or diesel or ordinary 87/89 octane petrol, BUT, you have to account for 50% of it being lost to waste heat in an internal combustion engine, and the weight of the engine and drivetrain. or weight of jet turbine+generator vs hydrogen tank + fuel cell PEM apparatus.
If you can find me the pdf datasheet for one that's above that I'd love to see it!
And even better a vendor link.
Note I am also referring to something like the actual usable watt hours from a battery before you discharge it below "permanently damaged" state, in the range starting from 100% SOC standard full voltage and manufacturer's do-not-exceed floor voltage. Such as on the NCR18650GA.
I don't doubt there are specialty rare "ask us for a price" low volume 300Wh/kg in circulation if you have the right contacts.
But the fuel cell uses hydrogen, which leaks inevitably (it slowly diffuses through all materials), and is an extremely potent greenhouse effect gas.
What's the efficiency of a battery-powered system in flight? E.g. disregarding ground charging and grid supply.
(edit) Wikipedia says ~95% for a generic electric motor and ~85% for a generic lithium-ion battery for a very rough estimate of about 80% efficiency in toto.
Deleted Comment
> But let's say you can climb the thing at 1000FPM and 100KIAS. That takes you an hour (covering roughly 250 nm?) to hit 65,000. If you spend an hour at cruise and then come down at 2000 fpm again covering 150nm ... you've just taken 2:30 block to go 900nm. What market does that make sense in? Might make a great autonomous cargo bird for Fedex.
--
> People spending 5 million on an airplane do not care about $180 of fuel difference per flight, and also that is only at altitude. If the climb rate of that airplane is 1,000fpm, which seems optimistic, it would take nearly an hour to get up there. If you are going on a 2 or 3 hour leg, fuel burn could be the same or worse.
https://www.beechtalk.com/forums/viewtopic.php?f=49&t=174467...
Longer analysis video:
https://www.youtube.com/watch?v=E38cc-4TvX8
Fundamentally, it could be nearly as cost efficient as large jets. The pilot wage is a small portion of the overall cost. A big reason big jets are big is because jet propulsion scales down poorly while electric scales down very well.
- Commercial planes begin at about 50-60 seats, less are non-viable.
Normal commercial size - 100 seats.
For air-dynamics, 3 times capacity enlarge (from 6 to 18) typically possible, but more changes too much.
And 3 times capacity in avia measured non linear, but with famous square-cube rule, which mean, change size will increase mass as square, but capacity as cube, so to got 3x capacity, need 1.443 increase of size (1.442^3=3.0046853).
We can always reimagine airports as well.
Deleted Comment
However with dwindling fuel supplies, I'm pretty positive we'll see the return of glorious, massive blimps. Powered by a fraction of the hydrogen it uses to float in the air, savvy meteorology, and thin solar panels.
A lot of things come down to scale. Small drones can run reasonable distances on LiPo, which scales very badly to larger vehicles.
What more there will be hydrogen fuel plants onsite at the airports
Additionally you'll see hydrogen in similar large systems such as rail and earth moving equipment.
Honestly the only question I have in the large vehicle systems is cargo ships. There's plenty of space and benefit to large solar wings expanding the vessel surface area that can fold up when necessary
If you see the efficiency gains and cost reduction in commercial grade PV continue, it's going to be unit cost economically superior fairly soon.
Alternatively there could be some mystery device that can get a net energy gain by processing sea water to hydrogen fuel. This doesn't look physically impossible but I haven't heard of any serious efforts to do so yet and personally I'd need a lot of convincing to be assured it wouldn't just be doing a new flavor of ocean polluting
8 MJ/liter for liquid hydrogen vs. 32 MJ/liter for gasoline
Size matters
https://edition.cnn.com/travel/article/airlander-10-air-nost...
And given how big % of fuel is needed for ascending to cruise height, I'd imagine you could have a decent % of the fuel in take-off tanks with thin walls, since those tanks only need to contain the fuel for less than 10 minutes anyway.
I could imagine future planes using hydrogen for take-off and batteries for cruising.
Drag nearly directly proportional to the cross section of the craft. Something blimp like would be necessarily slow, to stay efficient.
Dead Comment
Na thanks i take the train ;) But for good's i could image that.
We need to fly as little as possible, not to incentivize it even more. 80% less fuel consumption? Expect people flying 5 times more, and feeling like they are doing a favor to the environment. Jevons Paradox.
If, indeed, this can be made to work with a zero emission hydrogen power source, why would we seek to limit that air travel the same way we might seek to limit fossil fuel based planes ?
Are you suggesting that air travel - of any kind - is negative?
These go as follows.
---
Hey we have this AMAZING tech (supposedly). But wait, we're not going to commercialize / actually produce it even though if true it'd print money.
Look we have this (other) AMAZING tech, we are going to combine these so that's why we aren't showing Amazing Tech #1.
And repeat.
---
Most get rich books / authors / etc - if they had a way to actually beat for the forex market etc they wouldn't be selling $50/books on how to do it. Same thing here. if they had a massively efficient plane (with a prop - also efficient) they'd actually deliver.
This seems like a red flag and possibly indicates shenanigans.
For passengers who expect a flight with 4 first class-type seats, their competition isn't a minivan with wings like the beechcraft bonanza, it's a learjet with half the seats removed.
If laminar flow tech worked as they claimed, you wouldn't need hydrogen to be a market success.
Putting a hydrogen engine in it seems like a distraction.
Dead Comment