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Boeing's Hybrid Electric Airliner of the Future
fergus07 writes "Borne out of the same NASA research program that gave birth to MIT's D 'double bubble,' Boeing's Subsonic Ultra Green Aircraft Research (SUGAR) Volt concept is a twin-engine aircraft design notable for its trussed, elongated wings and electric battery gas turbine hybrid propulsion system — a system designed to reduce fuel burn by more than 70 percent and total energy use by 55 percent. The goal of the NASA supersonic research program is to find aircraft designs that will significantly reduce noise, nitrogen oxide emissions, fuel burn and air traffic congestion by the year 2035."
Actually Concord was generating 25% of BOAC's profits.
Flying wings have many excellent characteristics but mass passenger transport isn't one of them.
In order to accommodate large passenger loads the flying wing shape becomes abused which leaves behind many of the characteristics which make the flying wing attractive in the first place. Once you modify the flying wing shape to accommodate large passenger loads, you more or less have a shape which is portrayed in the designs presented. And once you accommodate construction/materials issues, it almost exactly looks like the designs presented.
In other words, I'm not really seeing a problem. But, as you mention, hopefully some designers won't be silent.
I had 'jet fuel' as on my list of things that wouldn't ever likely get replaced with electric storage, and now this reduces the list a bit. Can we just start putting up some modern nuclear reactors and get out of the Middle East then? We've got plenty of sources here for real oil needs.
No one has died of a radiation-related accident in the history of the U.S. civilian nuclear reactor program. but 10,000 or so Americans have died so far as a result of making war in the Middle East.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
Don't forget, the Concord was '70s technology. Even 90s technology could have done better.
The thing wasn't cheap, but there was no other option on Earth. There simply wasn't (and isn't) a way to get between NY and London faster. You can't buy a supersonic jet, and the military won't let you borrow one.
Comment forecast: Bits of genius surrounded by a sea of mediocrity.
Passengers like pressurized cabins, tubes are easy to build and keep pressurized. Complex shapes are not easy to build if you want to keep them pressurized.
it's not a huge pressure differential. Less than a few feet of water in reality.
All of the above was encrypted with a Quad ROT-13 method. Unauthorized decryption is in violation of the DMCA.
You realize that "just a few feet of water" is more like 22 feet (7.5m) of water.
At 35000 feet (10.5 km) cruising altitude for non-super sonic airplanes, air density is 25% of see level air density. 1 atmosphere is about the pressure of 10m of water column.
Everest is "just" 8848 m, and yet very few can breathe easily without several days acclimatization.
See altitude sickness. Even oxygen masks may not be enough at very low pressures.
While I don't refute your point, Pla123, I feel I should point out that passenger aircraft are not pressurized to sea level pressure. I believe--and no, it isn't fact, but I bet it's pretty close--that airliners are pressurized to ~7000 feet above sea level. What is that, like, 800mb? Anyway, there it is.
LH2 tanks require more insulation (meaning more weight). The planes can only carry so much fuel by volume. The maximum fuel capacity for a 737-NG is 26,000 liters. The density of Jet A at 15C is about 800g/L. The density of liquid hydrogen is 71g/L at 20K. At these densities, you get masses of about 21,000kg of Jet A and 1900kg of LH2. The specific energy of Jet A is about 43MJ/kg, and 143MJ/kg for LH2. At those levels, you get total stored energy of about 1.1 million MJ for Jet A, and only 270,000 MJ for LH2.
The numbers just don't work, and these don't consider the complicating factors from dealing with cryogenic fuels.
You can never go home again... but I guess you can shop there.
Actually lift also causes drag, so called induced drag; Wikipedia article here: http://en.wikipedia.org/wiki/Induced_drag
No, the coolest technology is now being used by off-the-books military "black" ops and weapons programs. It's always +25 years away for the rest of us, though.
I remember back in the 70's when people were being ridiculed for reporting sightings of large triangular craft which were very quiet and flew low over ranches out West.
Of course, they were stealth aircraft, which were being used in all sorts of black bag missions overseas. Today, it's probably something like HAARP or some ugly microwave mind control bullshit, which can get you called a tin-foil hat wearing nut just by mentioning it. In 25 years, when urban law enforcement is using it, nobody will remember calling you crazy. There were crazy people in the '60's who believed our very own government was using psychoactive drugs on unsuspecting citizens to see if they could be made to do very bad things. Can you imagine anything crazier? I bet those people were wearing tin-foil hats too.
I just hope Wikileaks stays in business, because I for one don't really care for my government doing sleazy black bag shenanigans without my knowledge, that always end up with some third world country hating us and sending terrorists twenty years later. Then, everybody will be saying "Gee, why do they hate us so much?" and nobody will hear the answer: "Because you used some sick heat ray on my village twenty years ago and my sister died a horrible death because of it."
Terrorists don't just pop out of the sky one day, hating America because we're such a swell bunch.
Now, what were we talking about?
You are welcome on my lawn.
The bypass ratio refers to the mass of air moved around the core to the mass moved through the core, not the ratio of thrust. For any given mass of air being put through the core, it will produce more thrust than the same ratio outside the core because it gets hotter/faster.
The press release is devoid of details, but a google search turns up that they're decoupling the jet engine (which generates the power) from the bypass fan (which generates most of the thrust).
For those not up to speed on jet engine technology, modern turbofans are essentially ducted propellers. The engine itself occupies a small section in the center. It burns fuel and throws the air it consumes out the back at a higher speed. This generates about 20% of the total thrust. The rest of the energy goes into spinning the bypass fan blades. Just like a propeller, they grab large chunks of air which never goes through the combustion chamber, and push it out the back at higher speed to generate about 80% of the thrust.
In current engine designs, the blades of the two are locked together (although some of the compressor blades inside the engine may rotate at a different speed). For the bypass fan blades to be spinning, the engine must also be on and spinning. The idea behind this hybrid is to decouple them so they can operate independently of each other. The bypass fan would be spun using an electric motor. I don't know the numbers involved, but theoretically that would mean you could always run the jet engine at its most efficient RPM to generate electricity, and even turn it off if there's little thrust required and the batteries have enough juice to run the bypass fan (e.g. descent).
And I'd give my left nut if we could send all the jerkoffs who drive whilst blabbing on the cell phone to the moon.