Boeing's Hybrid Electric Airliner of the Future 152
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."
Re:Supersonic?!? (Score:2, Informative)
Actually Concord was generating 25% of BOAC's profits.
Re:Obvious question (Score:4, Informative)
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.
So, just plastics and lube then? (Score:3, Informative)
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. [washingtonpost.com] but 10,000 or so Americans have died so far as a result of making war in the Middle East. [icasualties.org]
Re:Supersonic?!? (Score:3, Informative)
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.
Re:Obvious question (Score:3, Informative)
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.
Re:So, just plastics and lube then? (Score:3, Informative)
Plastics and lube can be made from plant materials, or hell with enough power you can make all the hydrocarbons you want from water and air.
Re:So, just plastics and lube then? (Score:5, Informative)
Re:So, just plastics and lube then? (Score:3, Informative)
These things are still going to be carrying oil of some description rather than charged up batteries for most of their energy requirements. The additional weight of batteries is not going to make sense for an aircraft.
Re:Obvious question (Score:3, Informative)
it's not a huge pressure differential. Less than a few feet of water in reality.
Re:So, just plastics and lube then? (Score:3, Informative)
I don't see where hybrids help here.
I can see where they could use stored electricity to shut engines off when landing to reduce noise, charge at the gate, and take off without engines as well.
That alone wouldn't affect efficiency necessarily, but would probably allow the use of louder engine types that might be able to reduce efficiency, and it would reduce the opposition to airports allowing them to be placed in better locations.
Re:Obvious question (Score:2, Informative)
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.
Re:Obvious question (Score:2, Informative)
Re:So, just plastics and lube then? (Score:2, Informative)
I'm not sure trains are a good model either; Diesel-electric trains are effective because the torque you need for starting & driving a train doesn't easily come from a diesel motor without lots of gearing and clutches that are complex, inefficient and potentially unreliable.
Electric motors can give you all the torque you want from a standing start and so they make it easier to use diesels, avoiding the need to electrify your rail network (partly the reason Britain went with Diesel-electric trains in the '50s - they didn't have the capital to electrify).
With aircraft it's less clear where the advantage is going to come from since the kerosene motor + generator combination (and its associated losses) in an aircraft isn't solving a clear problem like lack of torque in a train and power requirements with lots of peaks and troughs as in a car.
However, a big advantage (from an environmental point of view) could be the ability to take electrical power for flight - once you have this you can gradually feed in alternative or low carbon energy into your mix. This type of aircraft could be a first step in that direction.
Re:Forget Electric Hybrids (Score:3, Informative)
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.
Re:Obvious question (Score:2, Informative)
Re:Always 25 years (Score:3, Informative)
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?
Re:Props (Score:4, Informative)
Linked article is lacking details (Score:4, Informative)
For those not up to speed on jet engine technology, modern turbofans are essentially ducted propellers [wikipedia.org]. 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).
Re:Always 25 years (Score:1, Informative)
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.