Hypersonic missiles

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by bmcj, Apr 17, 2019.

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  1. Apr 17, 2019 #1

    bmcj

    bmcj

    bmcj

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    This video is interesting, though I cannot vouch for its accuracy. Mainly, I posted this because I thought the missile launches in the first few seconds were interesting.

     
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  2. Apr 17, 2019 #2

    ScaleBirdsScott

    ScaleBirdsScott

    ScaleBirdsScott

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    I'm frustrated that I added a view to one of those robo voice videos. They are a plague on the internet.

    The missile launches are cool tho.
     
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  3. Apr 18, 2019 #3

    Jimstix

    Jimstix

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    Hypersonic means flight speeds in excess of Mach 5. Mach 1 at STP is about 1100 feet per second (fps) or about 645 knots, if you prefer. So Mach 5 ~ 5500 fps or about 1 statute mile per second. Missiles traveling at that speed through the atmosphere anywhere below 100,000 ft ASL get hot, incandescently hot - like a meteor hot. This is a huge materials problem for the vehicle designers. Most standard aircraft-grade steels (4130, 4340, etc.) simply melt as though being heated with an acetylene cutting torch flame. Coatings of refractory metals helps, but not for long (like a couple of seconds). Ablative materials (like PICA) work but also have limited usage lives and don't like sharp edges. Densified carbon-carbon (Shuttle nose cap and wing leading edges) will work but are not GI-proof (or NASA proof).
    Oh, the stuff inside the vehicle doesn't like to get hot (warheads, guidance systems, fuel) so you need to insulate those items from the incandescent plasma on the outside.

    So the materials systems that are required for hypersonic flight are dauntingly difficult. I haven't mentioned stability and control issues or even how to get from 0 fps to 5500 fps. These too are difficult issues for the designer to overcome. It is much easier to animate a cartoon about hypersonic vehicles than to actually build and fly one. Jim
     

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