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Aerospace Turbojet Accelerator

  1. Jan 13, 2010 #1
    I have an idea which I cannot take to the production stage myself. I am sending it by way of getting contacts (electronic engineers, manufacturers or investors) for helping me with a 3 dimensional circuit manufacturing idea (already well worked out).

    Here goes:

    We already have turbojet engines on aircraft. Now the idea is to take the exhaust of two of them and pipe it into the same tube, then trough a charged grid that makes a large static electric field. The field must be strong enough to ionise much of the combustion products (Kerosene oxidated). The recombination after passing trough the grid should
    give extra thrust. The cool thing is that no fuel is needed for the ionisation - the grid can be recharged periodically from capacitor(s) which can be charged while the aircraft is on the ground.

    The turbojets may both be mounted skew ( / \ ) if neccessary as long as they produce the same thrust (the sideways thrust would cancell).

    The only theoretical concerns are then charge relaxation, dielectric brakedown, coronal discarge and the heat and corrosion resistance of the parts. Orientation by magnetic field may also be neccessary to ensure the recombination happens orderly.

    I can work out the charge relaxation concern, but the dielectric brakedown may need to be determined practically.

    If the exaust is an Omic conductor (likely since there must be ions in the gas due to the heat) the discharge of the grid due to charge relaxation can be estimated by permitivity/conductivity = charge relaxation time. A large value would give slow discharge. I will look for the data.

    If the discharge is too fast to be practical we may still have an advantage: speed boosts activated whenever the pilot decides.

    May work with ramjets too.
  2. jcsd
  3. Jan 13, 2010 #2


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    Staff: Mentor

    This is completely not my area of expertise, so I can be off, but the way I read it you have just stated "ionization and recombination gives more energy than we put into the system". That means energy from nowhere, doesnt' it?
  4. Jan 14, 2010 #3
    I think that any gain you might achieve will be far less then the losses introduced by skewing the jets from staright fore and aft.
  5. Jan 15, 2010 #4
    No, it isn't gaining more than putting in, the static electric field stores energy much like feul. It is just that the energy is put in while the aircraft is on the ground. The exhaust gasses are already heated so it takes less energy than usual to ionise them.

    For the other issue: there are jet aircraft with double inlets and just one outlet.
  6. Jan 15, 2010 #5


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    Staff: Mentor

    How much energy can you store in such a field as compared to the fuel? I mean - if that's am efficient way of storing a lot of energy, why is it not used to store energy in electric cars or whatever? WHy will it be more efficient in plane?

    So recombination doesn't give a lot of energy back.

    Looks to me energy conservation arguments are enough to show that the gain will be very small (if any).
  7. Jan 15, 2010 #6


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    This definitely isn't an area I am familiar with. Please explain the thrust producing mechanism as related to the ionization. I really do not understand where the extra momentum transfer is coming from to produce the extra thrust.
  8. Jan 15, 2010 #7
    There might be jets with two inlets and one outlet but I can't think of any with two jets and one outlet.
  9. Jan 19, 2010 #8
    I saw a plan for a Ion driven rocket. It is the same principle: action-reaction.

    Ions get accelerated in the magnetic field and recombination would change the gas particle's momentum (they get a kick in the right direction if the energy is released in the right direction).

    I haven't worked out how much yet but you can have large capacitors at kilo Volts (electron pressure). Cars do not have a jet of already heated gas.
  10. Jan 19, 2010 #9


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    Staff: Mentor

    From what you stated at first I understood it is recombination that should heat the gas increasing its speed, now you are talking about accelerating ions. It is not recombination that gives the ions their speed - ions got their momentum in the electric/magnetic field. Recombination is just to keep the engine charge neutral.

    These are completely different things, but I still feel like you are missing very basic energy conservation.
  11. Jan 19, 2010 #10
    The ionisation by the static electric field must increase the gas energy since energy is required to ionise, and some of it is recovered as kinetic energy as they recombine. The molecules need not collapse to their ground state after recombination.

    Just include the energy to make the static electric field in the energy conservation computation.
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