Quote from: Rocket Science on 02/28/2016 07:46 amQuote from: Robotbeat on 02/28/2016 01:59 amHybrids 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?~RobI 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.
Quote from: Robotbeat on 02/28/2016 01:59 amHybrids 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
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.
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.
Quote from: rocx on 02/28/2016 09:10 amQuote from: Rocket Science on 02/28/2016 07:46 amQuote from: Robotbeat on 02/28/2016 01:59 amHybrids 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?~RobI 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?
Quote from: Robotbeat on 02/28/2016 01:59 amHybrids 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....
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.
Quote from: Lee Jay on 02/29/2016 06:22 pmQuote from: Robotbeat on 02/28/2016 01:59 amHybrids 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.
Quote from: Robotbeat on 03/01/2016 12:32 amQuote from: rocx on 02/28/2016 09:10 amQuote from: Rocket Science on 02/28/2016 07:46 amQuote from: Robotbeat on 02/28/2016 01:59 amHybrids 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?~RobI 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.
Again, this is what is ALREADY done for electric cars. No doubt we'll be /more/ clever about this in the future, not less.
Quote from: Robotbeat on 03/01/2016 12:48 amQuote from: Lee Jay on 02/29/2016 06:22 pmQuote from: Robotbeat on 02/28/2016 01:59 amHybrids 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.
Quote from: Robotbeat on 03/01/2016 12:55 amAgain, 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.
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,...
Quote from: Lee Jay on 03/01/2016 01:05 amA $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).
Quote from: Robotbeat on 03/01/2016 01:20 amQuote from: Lee Jay on 03/01/2016 01:05 amA $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.
Quote from: Star One on 02/29/2016 10:06 pmQuote from: robertross on 02/29/2016 07:55 pmWell 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
Quote from: robertross on 02/29/2016 07:55 pmWell 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.
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)