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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."
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.
A few month ago, I sat in a pub watching (live) an Astronaut operating on the internals of the Hubble Space Telescope. On my phone.
We live in the goddamn future!
This story is somewhat of a dupe (too lazy to look up the original, though it was less than a year ago), and this point was brought up then too.
When you're talking about advanced aircraft, the "25 years effect" is not the same as it is for overhyped things like fusion power; here, there's actually a reason. Aircraft take a loooooooong time to go from concept to flight: recall that Airbus starting thinking about the A380 in 1988, made it an official project in 1994, and it started commercial flight in 2007. And that's for a conservative design that was just building on existing principles. For a radical, untested design it would be considerably longer. Looking at it from that point of view, 2035 is actually a very reasonable target.
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Look at diesel-electric trains for the model, not hybrid cars.
Another problem with a flying wing passenger aircraft is the fact that there won't be many, if any, window seats. Okay, minor problem? What about the forces that would act on people towards the wingtips when banking? A relatively minor turn that would barely be noticed in a tubular airframe would be magnified into a fifteen foot drop or rise towards the edges. Now imagine trying to land in turbulent, stormy weather, and being really far from the center axis of the aircraft. Whatever money would be saved by the efficient wing design would be eaten up by barf bags and steam cleanings of the cabin after every flight.
Jet engines are already de-facto propeller engines. If you call it a "Fan" it doesn't sound as scary as "Propeller." In a high bypass turbofan engine such as those found in most modern aircraft, most of the thrust is produced by the fan part of the turbofan. For example, the CF-34 jet engine has a bypass ratio of 80% or better. This means 80% of the thrust is produced by spinning a fan. Newer designs like the Rolls-Royce Trent 800 get 84% thrust from the bypass fan. Basically, anything that can create radial motion can be use to turn that fan. Electric, steam, compressed air, .... {insert physics here}.
This is a boring sig
I am no aerospace engineer, about as far from it as you can get, but I would think that wing = drag.
/. On an airplane, wing = lift. And since the purpose of the airplane is to go up, lift = good. The part the people sit in, that uniform shaped tube body, equals drag. An airplane shaped like a big wing could thus lift the most and drag the least. (see: Northrop YB-49)
Congrats on accidentally making the wrongest statement ever on
A tube body can actually produce some lift if it's shaped correctly but it's very expensive to manufacture and tricky to design (see: Super Constellation).
Your future is happening 40 years after I sat at my home watching (live) an Astronaut walking on the Moon.
I would gladly exchange all the cellphones in the world for being able to walk on the moon.
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.
obscure?
Definitely obscure. "Ecological" cars and airplanes? Carbon-powered? Obscure motivations? Trains are 100% electric, infinitely safer, more spacious, smaller footprint than roads, etc. On short routes, they can be faster than flying, after factoring taxis and airport waits. And, there are bar-cars. -- http://gizmodo.com/5434582/the-fastest-train-in-the-world
Build your own energy sources from scratch. http://otherpower.com/
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).