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Thread: Can Electricity and Water substitute current fuel for airplanes?

  1. #1 Can Electricity and Water substitute current fuel for airplanes? 
    Forum Cosmic Wizard icewendigo's Avatar
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    Can airplanes be built so that they use hydrogen and oxygen made by separating these from water (with electricity)?

    Would such a plane use a rocket engine, or a modified version of a current reactor, or could you make a hybrid engine that can combine aspects of rocket engines and reactors?

    Would it be preferable to have a wing design (like B2 etc) to have a larger wing volume to store the hydrogen and oxygen?

    How would such a plane compare to a current plane? (less range or equivalent range?)

    Could the hydrogen fuel be charged with electricity upon fueling so that you could discharge electricity as it is expelled?


    If a plane was designed to land on water, had photovoltaic cells on the upper wing and fuselage, could it use solar energy to pump water and split it into hydrogen and oxygen to refuel in a remote region?.


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    No to all of the above


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  4. #3  
    Forum Cosmic Wizard icewendigo's Avatar
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    Thanks fizzlooney

    can anyone else care to explain in a few words why not?

    thanks in advance
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  5. #4  
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    Reactors are heavy and large. Airplanes don't fly well with that. The recombination of H and O will always give you less enrgy than that required to split it.
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    The biggest problem with using hydrogen as an airplane fuel is its low energy density by volume. The gas can be compressed or liquified, but that requires heavy storage tanks and/or cooling equipment.
    Hydrogen economy - Wikipedia, the free encyclopedia
    Although molecular hydrogen has very high energy density on a mass basis, partly because of its low molecular weight, as a gas at ambient conditions it has very low energy density by volume. If it is to be used as fuel stored on board the vehicle, pure hydrogen gas must be pressurized or liquefied to provide sufficient driving range. Increasing gas pressure improves the energy density by volume, making for smaller, but not lighter container tanks (see pressure vessel). Achieving higher pressures necessitates greater use of external energy to power the compression. Alternatively, higher volumetric energy density liquid hydrogen or slush hydrogen may be used. However, liquid hydrogen is cryogenic and boils at 20.268 K (–252.882 C or –423.188 F). Cryogenic storage cuts weight but requires large liquification energies. The liquefaction process, involving pressurizing and cooling steps, is energy intensive. The liquefied hydrogen has lower energy density by volume than gasoline by approximately a factor of four, because of the low density of liquid hydrogen — there is actually more hydrogen in a liter of gasoline (116 grams) than there is in a liter of pure liquid hydrogen (71 grams). Liquid hydrogen storage tanks must also be well insulated to minimize boil off. Ice may form around the tank and help corrode it further if the liquid hydrogen tank insulation fails.

    The mass of the tanks needed for compressed hydrogen reduces the fuel economy of the vehicle. Because it is a small molecule, hydrogen tends to diffuse through any liner material intended to contain it, leading to the embrittlement, or weakening, of its container.
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  7. #6  
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    1. too expensive
    2. it won't feel good on such plane....
    3. dangerous, and may be bad to the entire design of plane
    6. our solar cell is not so efficient, you need to wait a long time, even they are, still to expensive, why not just store the electricity in some other kind of battery or super capacitor...
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    Forum Cosmic Wizard icewendigo's Avatar
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    So if there werent any jet fuel or petroleum derivatives, what would be the next best thing to use to propel air liners on intercontinental flights?
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    We can synthesize fuel from trees and plant oil. I think the process is called "cracking" or something;which we crack complex organic molecule into a simple petrol-like molecule or into ethanol. As a result: we rely on plant for fuel. Also don't forget about biomass: which use bacteria to convert carcass to methane. I think there is also a method to convert methane into more petrol-like fuel (correct me if I am wrong).And you can use algea to make hydrogen from water. Currently there is a rumor where companies try to bio-engineer this algea to be more efficient producer of hydrogen. Think of "bio-reactor" filled with green stuff that produce hydrogen when exposed to sunlight.
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  10. #9  
    Brassica oleracea Strange's Avatar
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    Given the problems with hydrogen, it may be better to make hydrocarbons from renewable resources: Scientists Use Sunlight to Make Fuel From CO2
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  11. #10  
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    Quote Originally Posted by Strange View Post
    Given the problems with hydrogen, it may be better to make hydrocarbons from renewable resources: Scientists Use Sunlight to Make Fuel From CO2
    Isn't the problem with co2 scrubbers the cost of sequestering? And that seems to resolve it, so why the hell arent we doing this?
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    Hydrogen has property of making metals in contact more brittle as well. You would carry oxygen instead of using ambient oxygen in air, for which there is no weight penalty.

    Maybe sub-orbital flight via rocket vs conventional airliner flight profile: Ithacus

    Sea Dragon
    The bravest are surely those who have the clearest vision of what is before them, glory and danger alike, and yet notwithstanding go out to meet it.- Thucydides
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  13. #12  
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    Quote Originally Posted by icewendigo View Post
    So if there werent any jet fuel or petroleum derivatives, what would be the next best thing to use to propel air liners on intercontinental flights?
    Nukes. Gas-core nuclear reactor rocket engine, better than combustion fuels because hotter.
    The bravest are surely those who have the clearest vision of what is before them, glory and danger alike, and yet notwithstanding go out to meet it.- Thucydides
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    Found cooooollll forum with many interesting speculations which may be of interest to partcipants on this thread, kudos to all and OP in particular:

    Secret Projects Forum - Index
    The bravest are surely those who have the clearest vision of what is before them, glory and danger alike, and yet notwithstanding go out to meet it.- Thucydides
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  15. #14  
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    Quote Originally Posted by icewendigo View Post
    So if there werent any jet fuel or petroleum derivatives, what would be the next best thing to use to propel air liners on intercontinental flights?
    unfortunately, none yet can replace oil fuel.
    actually, my point is why not use another transportation way instead of planes...at least in some lines we can use trains, like asia to europe, trains are more clean and capable to carry more people. of cause, the speed may be slow, but train techniques are getting better every year.
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    Use your h2 to fill a gas bag of an Airship to compensate for the weight of h2 storage containers. Use metal hydride for lower pressure hydrogen storage. See 'Smart tanks". Hydrogen has greastest possible energy density of any chemical fuel and burns totally cleanly, those two considerations alone make it worth while to find away to use it.
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  17. #16  
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    Do the physics. It doesn't work.
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    Quote Originally Posted by MeteorWayne View Post
    Do the physics. It doesn't work.
    There is no law that prevent the use Hydrogen as fuel. What are you saying? Are you proposing that people who use Hydrogen as fuel doesn't know physic???
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    Quote Originally Posted by msafwan View Post
    Quote Originally Posted by MeteorWayne View Post
    Do the physics. It doesn't work.
    There is no law that prevent the use Hydrogen as fuel. What are you saying? Are you proposing that people who use Hydrogen as fuel doesn't know physic???
    People who try to use hydrogen fuel to fly an airplane don't know physics.
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  20. #19  
    Forum Cosmic Wizard icewendigo's Avatar
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    But one of the most famous Rocket, Saturn V, used LH2
    /
    LOX as propellant, H2 and O, it appears to work for a rocket, and thats pretty close to water, right?


    SCI-FI Question:
    Lets say humans find a cylindrical "alien" advanced nano-tech device used as a rocket engine, the size of two garbage cans piled on on top of the other, that takes water on one end, splits it with (stored) energy, achieves fusion with some of the isolated hydrogen, uses a small part of the resulting energy to feed-back split incoming water and some to feed-back trigger fusion, while the rest of the energy generated is used to accelerate(magnetically/combustion/explosion?) the H2 and O and He (resulting from the fusion) out of the other end. Would this be somewhat plausible sci-fi or is there some blatant physics law I've missed thats being broken?
    Last edited by icewendigo; March 20th, 2012 at 08:40 AM.
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  21. #20  
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    Quote Originally Posted by icewendigo View Post
    But one of the most famous Rocket, Saturn V, used LH2
    /
    LOX as propellant, H2 and O, it appears to work for a rocket, and thats pretty close to water, right?

    An airplane would not need the LOX. It would just burn air. The Saturn V did not need a refrigeration system, because it was burning the hydrogen right away. While in the parking orbit, they let it boil off to cool the liquid hydrogen.
    Saturn V - Wikipedia, the free encyclopedia
    This parking orbit was quite low by Earth orbit standards, and it would have been short-lived due to aerodynamic drag. This was not a problem on a lunar mission because of the short stay in the parking orbit. The S-IVB also continued to thrust at a low level by venting gaseous hydrogen, to keep propellants settled in their tanks and prevent gaseous cavities from forming in propellant feed lines. This venting also maintained safe pressures as liquid hydrogen boiled off in the fuel tank. This venting thrust easily exceeded aerodynamic drag.
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