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Thread: 150 - 200 lb thrust jet engines?

  1. #31
    Registered User WonderousMountain's Avatar
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    Re: 150 - 200 lb thrust jet engines?

    Titanium is expensive period, but Inconel and other nickel alloys are semi-reasonable with high usable temperatures. The design of a flight-grade turbojet is a serious undertaking (we all want you to make one), that might take years to work the kinks out.

    Maybe you could look at "clustering" smaller jets, this would have several benefits, it would create some level of redundancy that might just save your life. It would reduce the development time of the project and possibly the cost. Properly positioned they might create a vortex that could keep your legs from imitating something from KFC. Although, there's something to be said for the benefit of having a flight grade jet engine under your patent.....

    Wonderous Mountain

  2. #32
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    Re: 150 - 200 lb thrust jet engines?

    Machining the parts isnt a problem, I have a job as a CNC machinist and my boss let's us dick around with personal projects.

    What is the combustion temp of flight grade fuel?

  3. #33
    Moderator autoreply's Avatar
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    Re: 150 - 200 lb thrust jet engines?

    Quote Originally Posted by Kroni495 View Post
    Machining the parts isnt a problem, I have a job as a CNC machinist and my boss let's us dick around with personal projects.
    Designing is a problem..
    What is the combustion temp of flight grade fuel?
    Pretty low actually, far below 1000C is I recall correctly. But the problem is that you can only produce power if you compress the air a couple times (that's how any fossil fuel engine works). That usually brings you temperatures where Inconel would melt in the hot spots. There's a reason it's expensive. Even the modelling turbines (90 lbs thrust) cost 15K US$ and that company does pretty much what you want and they can spread the design and programming cost over a lot of engines. (AMT Netherlands)
    Kennis vermenigvuldig je door het te delen.
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  4. #34
    Registered User delta's Avatar
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    Re: 150 - 200 lb thrust jet engines?

    A company in England had a small tfe with about a 24" disk at Oshkosh in 04. The turbine itself was probably in the 20 to 40 lb class and similar to what you'd find on a RC jet. I believe they were talking over200# thrust with something that couldn't have weighed more than 20#. It was exciting to me because of the sfc factor. I tried to contact them a few months later without success, and haven't heard anything about them since.
    It sounds like to me all you may be after is thrills. If that is the case, explore the use of rockets. I hope eventually you will turn your attention towards utility...


    Rick

  5. #35
    Super Moderator orion's Avatar
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    Re: 150 - 200 lb thrust jet engines?

    Quote Originally Posted by Kroni495 View Post
    Machining the parts isnt a problem, I have a job as a CNC machinist and my boss let's us dick around with personal projects.
    The machines that fabricate turbine parts are generally the higher end models that can maintain extremely tight tolerances all day long. Given the speed of a small turbine (some turn up to 200k rpm), even a tiny imbalance could instantly convert it into your own private grenade. Basically, even if you did have a good design (a whole separate subject in of itself), the likelihood that you'd have a machine capable of this level work is relatively unlikely, and even less likely is that anyone would let you dink around with it on non-work stuff.
    "To live is to learn; to learn is to live" (author unknown)

  6. #36
    Registered User Dan Thomas's Avatar
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    Re: 150 - 200 lb thrust jet engines?

    Most homebuilders have no idea of the complexity of making turbine engines, especially any engine that doesn't drink fuel at horrendous rates. The pressures and temperatures inside a turbine are awesome, the centrifugal forces are awesome, the speeds are awesome. Much easier to build a piston engine from scratch.

    150 - 200 lb thrust jet engines?-36b0f636.jpg

    The cooling systems for such engines are similarly complicated. This is ONE blade from a turbine wheel. The holes supply bleed air to insulate the blade from the superheated combustion gases. All the turbine blades need cooling, and all the turbine nozzle blades need it. The combustion cans need similar treatment. Small, model-type turbines use lower pressures and lower temperatures to avoid it, thus wasting lots of fuel.

    150 - 200 lb thrust jet engines?-aerospace_engineering_262329101.png

    Dan

  7. #37
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    Re: 150 - 200 lb thrust jet engines?

    You would have a better thrust per pound using rockets with about the same fuel burn rate of a jet.
    The Jet packs flying on Hydrogen Peroxide is about the same amount of fly time you will get with a jet . Maybe even less with a jet accounting for start and spool up time .
    It will be quite a daunting task to carry enough fuel safely, In both the physical containment department , and in the weight and balance department as it is used up , for an "extended " flight . Let alone the "method" of the flight being discussed.
    If your team wanted to "test designs" of the "flying boots' I would go with Hydrogen peroxide rockets .They are cheap and easy to make. Its the "Boots" that's going to make or brake the concept . Not the power plant .
    Last edited by inventing_man; June 26th, 2011 at 09:16 PM.

  8. #38
    Registered User Voyeurger's Avatar
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    Re: 150 - 200 lb thrust jet engines?

    Quote Originally Posted by Kroni495 View Post
    Machining the parts isnt a problem, I have a job as a CNC machinist and my boss let's us dick around with personal projects.
    Sounds like a pretty cool and casual boss.
    Voyeurger
    "Spitting In The Eye of Doubt"

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