Author Topic: NASA Administrator to Make X-Plane Announcement at Reagan National Media Event  (Read 33488 times)

Offline Robotbeat

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Hybrids are neat and all, but full-electric is where it's at. Ultra-high-performance lithium-ion and lithium-sulfur can do 300-400Wh/kg, which should do 1000km with some of those advanced designs, if you're clever. With lithium-air batteries (which need a lot of process development to get to any kind of decent cycle life) using the newer designs, you could get range comparable to all current jet liners. And potentially supersonic electric flight.
Chris, do you have a projected turn-around time for re-charge on such a design?

~Rob

I strongly suppose that if a fully battery operated airplane enters commercial operation, it would need to come with a quick battery swap option to keep turnaround time low and thermal loads acceptable.
That is an option, but why? A Tesla can recharge to 80% in 40 minutes. Even faster charging is possible and is done with Proterra's fast-charging electric buses in just 5 minutes. So could an aircraft.

If you wanted to keep thermal loads lower (but doesn't seem to be too much of a problem for Teslas), you could hook up to a chiller along with power.
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Oh my, checked whois and NACASpaceFlight.com is available! Quick, hit the mod button and let Chris know!

Kinda bummed it wasn't something that had more near term potential. Like the blended body or the turbo electric hybrid fan. I wonder why they went for sizzle.

This one can be spread around to more centers???
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Offline Lee Jay

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Hybrids are neat and all, but full-electric is where it's at. Ultra-high-performance lithium-ion and lithium-sulfur can do 300-400Wh/kg, which should do 1000km with some of those advanced designs, if you're clever. With lithium-air batteries (which need a lot of process development to get to any kind of decent cycle life) using the newer designs, you could get range comparable to all current jet liners. And potentially supersonic electric flight.
Chris, do you have a projected turn-around time for re-charge on such a design?

~Rob

I strongly suppose that if a fully battery operated airplane enters commercial operation, it would need to come with a quick battery swap option to keep turnaround time low and thermal loads acceptable.
That is an option, but why?

Do you realize how much power you're talking about here?

Putting, say, 25MWh into a plane in, say, 30 minutes is going to take 50 MW of power.  That's more than comes into the entire airport, most likely.  Now multiply by, say, 40 planes on charge at once.  That's 2,000MW which is about half of the average power consumption in my entire control area.

And do you know what a cable carrying 50MW safely looks like?  It's going to have to be medium voltage.  Let's say it's 13.2kV three-phase.  That's 2,200A.  That's 4 3-conductor 500kcmil mining cables, each one 3 inches in diameter weighing 6 pounds per foot and costing about $50 per foot.
« Last Edit: 03/01/2016 12:48 AM by Lee Jay »

Offline Robotbeat

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Hybrids are neat and all, but full-electric is where it's at. Ultra-high-performance lithium-ion and lithium-sulfur can do 300-400Wh/kg, which should do 1000km with some of those advanced designs, if you're clever.

I did the math here, with some assumptions.

For a vehicle like a 737, a 1000km flight will consume 7,500kg of fuel or the energy in a 62,500kg 400Wh/kg battery (with 100% conversion efficiency to shaft power).  Aerodynamic and propulsion efficiency isn't going to close that gap....
...except that's exactly what NASA aeronautics are proposing. Distributed propulsion and the blended wing concept, sucking the slowed boundary layer into the turbofans can make a huge difference. Some of the concepts are capable of 50% or even 60% reduction in fuel consumption. To take your example, that would mean 31,250kg battery mass versus 85100kg for 737-800 maximum take-off weight.

Consider that long-range jets like the 777 can be 50% fuel by mass. But you could increase that to 60 or even 75% (GlobalFlyer was able to achieve over 80%), combined with improvements in structural mass, perhaps even using the batteries as structural elements, would allow 1000km to definitely be possible with the battery tech I described. I had also done these calculations, I wasn't just making them up.

As I said, you have to be clever which you weren't bothering to do. :)
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Offline Lee Jay

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Hybrids are neat and all, but full-electric is where it's at. Ultra-high-performance lithium-ion and lithium-sulfur can do 300-400Wh/kg, which should do 1000km with some of those advanced designs, if you're clever.

I did the math here, with some assumptions.

For a vehicle like a 737, a 1000km flight will consume 7,500kg of fuel or the energy in a 62,500kg 400Wh/kg battery (with 100% conversion efficiency to shaft power).  Aerodynamic and propulsion efficiency isn't going to close that gap....
...except that's exactly what NASA aeronautics are proposing. Distributed propulsion and the blended wing concept, sucking the slowed boundary layer into the turbofans can make a huge difference. Some of the concepts are capable of 50% or even 60% reduction in fuel consumption. To take your example, that would mean 31,250kg battery mass versus 85100kg for 737-800 maximum take-off weight.

Consider that long-range jets like the 777 can be 50% fuel by mass. But you could increase that to 60 or even 75% (GlobalFlyer was able to achieve over 80%), combined with improvements in structural mass, perhaps even using the batteries as structural elements, would allow 1000km to definitely be possible with the battery tech I described. I had also done these calculations, I wasn't just making them up.

As I said, you have to be clever which you weren't bothering to do. :)

It's still 4 times the mass of the fuel it replaces, and that's way too much.  It means lower efficiency because you have to carry the batteries around.

Batteries aren't even ready for prime time for cars yet, much less airplanes.

BTW, this is coming from a power EE who has spent 30 year flying all-electric RC aircraft, so it's not like I'm opposed to the technology or something.

Offline Robotbeat

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Hybrids are neat and all, but full-electric is where it's at. Ultra-high-performance lithium-ion and lithium-sulfur can do 300-400Wh/kg, which should do 1000km with some of those advanced designs, if you're clever. With lithium-air batteries (which need a lot of process development to get to any kind of decent cycle life) using the newer designs, you could get range comparable to all current jet liners. And potentially supersonic electric flight.
Chris, do you have a projected turn-around time for re-charge on such a design?

~Rob

I strongly suppose that if a fully battery operated airplane enters commercial operation, it would need to come with a quick battery swap option to keep turnaround time low and thermal loads acceptable.
That is an option, but why?

Do you realize how much power you're talking about here?

Putting, say, 25MWh into a plane in, say, 30 minutes is going to take 50 MW of power.  That's more than comes into the entire airport, most likely.  Now multiply by, say, 40 planes on charge at once.  That's 2,000MW which is about half of the average power consumption in my entire control area.

And do you know what a cable carrying 50MW safely looks like?  It's going to have to be medium voltage.  Let's say it's 13.2kV three-phase.  That's 2,200A.  That's 4 3-conductor 500kcmil mining cables, each one 3 inches in diameter weighing 6 pounds and costing about $50 per foot.
No. You actively cool the cables, which allows you to carry a LOT more current in the same physical size. That's exactly what Tesla does for their newer Supercharging stations, so the ~300Amp cable they use is much smaller and lighter than you might suppose if you just look up the number in Handbook of Electronic Tables and Formulas or a website.

And remember that the hose for refueling jets can be ~5 inches in diameter.

Again, this is what is ALREADY done for electric cars. No doubt we'll be /more/ clever about this in the future, not less.
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Offline Lee Jay

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Again, this is what is ALREADY done for electric cars. No doubt we'll be /more/ clever about this in the future, not less.

Batteries have to get about 5 fold better than they are in energy density and cost per kWh before they are ready for this type of thing.  Baring a breakthrough, that's a long way to go.

Offline Robotbeat

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Hybrids are neat and all, but full-electric is where it's at. Ultra-high-performance lithium-ion and lithium-sulfur can do 300-400Wh/kg, which should do 1000km with some of those advanced designs, if you're clever.

I did the math here, with some assumptions.

For a vehicle like a 737, a 1000km flight will consume 7,500kg of fuel or the energy in a 62,500kg 400Wh/kg battery (with 100% conversion efficiency to shaft power).  Aerodynamic and propulsion efficiency isn't going to close that gap....
...except that's exactly what NASA aeronautics are proposing. Distributed propulsion and the blended wing concept, sucking the slowed boundary layer into the turbofans can make a huge difference. Some of the concepts are capable of 50% or even 60% reduction in fuel consumption. To take your example, that would mean 31,250kg battery mass versus 85100kg for 737-800 maximum take-off weight.

Consider that long-range jets like the 777 can be 50% fuel by mass. But you could increase that to 60 or even 75% (GlobalFlyer was able to achieve over 80%), combined with improvements in structural mass, perhaps even using the batteries as structural elements, would allow 1000km to definitely be possible with the battery tech I described. I had also done these calculations, I wasn't just making them up.

As I said, you have to be clever which you weren't bothering to do. :)

It's still 4 times the mass of the fuel it replaces, and that's way too much.
No it's not.
Quote
It means lower efficiency because you have to carry the batteries around.
Yet you can access any source of electricity, which could be very cheap besides not polluting.

Quote
Batteries aren't even ready for prime time for cars yet, much less airplanes.
As a physicist who drives an electric car every day, I completely disagree. The battery technology is more than ready. It's the battery price that must come down for electric cars to be mass-market, and given the contract that GM has signed with LGChem (not to mention Tesla's Gigafactory), battery prices are well on their way to being cheap enough. But the batteries themselves are MORE than capable.
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Offline Robotbeat

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Again, this is what is ALREADY done for electric cars. No doubt we'll be /more/ clever about this in the future, not less.

Batteries have to get about 5 fold better than they are in energy density and cost per kWh before they are ready for this type of thing.  Baring a breakthrough, that's a long way to go.
To replace long-haul jets, perhaps. But NOT to replace short-haul. 400kWh/kg is enough for that (which we've already achieved in the lab), and initially even the 300Wh/kg we produce today would be interesting for some niches. And the prices are already low enough because you cycle the short-haul jets MANY times a day.

Now is the time to start designing these electric jets, because it takes a really long time for them to go from drawing board to first flight.

And 5 fold improvement is certainly possible using lithium-air batteries. I've seen some lithium-air batteries in person, it's not just a powerpoint idea. Conservatively speaking, we're probably a decade or two from achieving good cycle performance with lithium-air, but that's about how long it takes for a new jet to go from idea to service these days.
« Last Edit: 03/01/2016 01:08 AM by Robotbeat »
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Offline Lee Jay

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A $130,000 Tesla P90D couldn't even get me to visit my family, and it's only 2 hours away.  No Superchargers along the way, 290 mile round trip, can't charge there, often have to do it in bitter cold (i.e. -10F) sometimes getting stuck on the highway for an hour waiting for a wreck to be cleared with the heat blasting.  Definitely not even close to ready for prime time.

My $25,000 Prius makes the round trip and takes me to and from work for a week with no problem.

I generally refuel when my range gets down to about 250 miles, holding that much in reserve.  And my kids are impatient about fueling even when it takes 3 minutes.  40 minutes is a total non-starter.

Don't forget, airplanes have to have a 30 minute flight reserve minimum, usually closer to 45 minutes.  I didn't add that in to my mass estimates.

Offline Rocket Science

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The shortest turnaround for a commercial aircraft is about 25 minutes on average for a Southwest 737. Their aim was 10 minutes. Others are about 30-45 minutes.
"The laws of physics are unforgiving"
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Offline Robotbeat

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A $130,000 Tesla P90D couldn't even get me to visit my family, and it's only 2 hours away.  No Superchargers along the way, 290 mile round trip, can't charge there,...
Your family doesn't have a 120V outlet? That I find hard to believe. Additionally, the fact there are not superchargers along the way is a temporary problem. And a larger battery could also be used except for the cost. 500 mile range could easily be done with existing batteries.

I don't know what your off-topic anecdote is supposed to mean except that you can find corner cases where electric cars have trouble (but again, no 120V outlet? I don't believe you). (But so would some gasoline cars if there were no gas stations.)
« Last Edit: 03/01/2016 01:30 AM by Robotbeat »
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Let's not go TOO far down the rathole of whether batteries are ready for planes yet...
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline Lee Jay

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A $130,000 Tesla P90D couldn't even get me to visit my family, and it's only 2 hours away.  No Superchargers along the way, 290 mile round trip, can't charge there,...
Your family doesn't have a 120V outlet?

Not outside and not out on the street where I park.  Besides, 4 miles per charge hour would barely make a dent.  Maybe I'd get 30-40 extra miles of range, which is far from enough.

Quote
That I find hard to believe. Additionally, the fact there are not superchargers along the way is a temporary problem. And a larger battery could also be used except for the cost. 500 mile range could easily be done with existing batteries.

I don't know what your off-topic anecdote is supposed to mean except that you can find corner cases where electric cars have trouble (but again, no 120V outlet? I don't believe you).

A supercharger station is not a useful thing anyway.  Too slow.  I can put 7 miles of range in my current car every second.  The effective charge rate is about 5MW - 40 times faster than the highest power supercharger.

I could give you dozens of other cases of places I've been where a P90D couldn't go without a tow back.

Offline Robotbeat

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A $130,000 Tesla P90D couldn't even get me to visit my family, and it's only 2 hours away.  No Superchargers along the way, 290 mile round trip, can't charge there,...
Your family doesn't have a 120V outlet?

Not outside and not out on the street where I park.  Besides, 4 miles per charge hour would barely make a dent.  Maybe I'd get 30-40 extra miles of range, which is far from enough.

Quote
That I find hard to believe. Additionally, the fact there are not superchargers along the way is a temporary problem. And a larger battery could also be used except for the cost. 500 mile range could easily be done with existing batteries.

I don't know what your off-topic anecdote is supposed to mean except that you can find corner cases where electric cars have trouble (but again, no 120V outlet? I don't believe you).

A supercharger station is not a useful thing anyway.  Too slow.  I can put 7 miles of range in my current car every second.  The effective charge rate is about 5MW - 40 times faster than the highest power supercharger.

I could give you dozens of other cases of places I've been where a P90D couldn't go without a tow back.
You also cannot drive a combustion engine vehicle indoors due to fumes. You are also completely at the mercy of fossil fuel infrastructure. While I enjoy this nice back and forth, this is off-topic.

Airplanes are hooked up to shore power already while at the gate. There's plenty of time for charging with a properly-engineered system.

I've answered basically all your objections pretty clearly. Yes, you CAN get 1000km range with cleverness, just as I originally said. No, the charging cable DOESN'T have to be 3 inches thick (which is smaller than the 5 inch diameter fueling hoses). Is it possible you are wrong about electric flight?
« Last Edit: 03/01/2016 02:06 AM by Robotbeat »
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Offline Rocket Science

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Lots of surface area on an aircraft, they could use spayed on Photovoltaic Paint to help generate power continuously during the day...

http://www.nanoflexpower.com/automotive
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Again... vehicle battery range is off topic. Spraying solar cell paint on wings is off topic. Stick to the NASA related aspects here please. NASA announced they are pursuing QueSST  not the other alternatives.
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Offline Robotbeat

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Actually, that's not true. NASA is doing a bunch of X-Planes, the Quiet supersonic transport being just one of them. Many are electric propulsion (usually hybrid as the goal, but will still use batteries, and the early prototypes are all pure electric since that's a lot simpler).
« Last Edit: 03/01/2016 03:18 AM by Robotbeat »
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Offline Star One

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Oh my, checked whois and NACASpaceFlight.com is available! Quick, hit the mod button and let Chris know!

Kinda bummed it wasn't something that had more near term potential. Like the blended body or the turbo electric hybrid fan. I wonder why they went for sizzle.

Because it's the most viable and far along as an idea & probably the easiest to translate to the commercial world. The others are kind of further out from this stage.

This article seems to have a bit more detail on this announcement & history.

https://www.flightglobal.com/news/articles/nasa-selects-lockheed-martin-to-design-supersonic-x-422539/
« Last Edit: 03/01/2016 06:53 AM by Star One »

Online Blackstar

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Well not to stomp on the parade, and this would be Chris' call, but is seems to me this announcement is in the realm of aeronautics, not spaceflight.

(though personally I think it's well overdue to have another supersonic aircraft, and it's wickedly cool stuff)

Have you forgotten what the 'A' stands for in NASA. This is a personal bugbear for me.

Not at all. I have also been following this thread. I also follow the yearly budgets and appropriations that define the aeronautics portion of NASA's budget.

However, people also seem to forget the name of this site: NASASpaceflight. This is about all things related to space. Certain relates topics have been challenged before, such as unmanned spaceflight & science, as there are

A useful skill that I have developed over time is that if it doesn't interest me, I ignore it. Saves much more time than complaining.

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