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    Default Humidity

    So there's something I've not been able to find much on, how air humidity effects shuttle speed.

    I'm assuming higher humidity results in lower shuttlespeed, because the air is 'denser' so to speak.

    I'm in an area that reaches 0 C (sometimes colder), but still retains upwards of 90% humidity, and I'm wondering how this would effect shuttle speed.

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    Moist air is actually lighter and less dense than dry air.

    Humidity contributes to shuttles travelling faster.

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    Huh, that's interesting. I didn't expect water molecules to effectively replace other molecules in the other, but rather attribute to it. Thanks!

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    Quote Originally Posted by Charlie-SWUK View Post
    Huh, that's interesting. I didn't expect water molecules to effectively replace other molecules in the other, but rather attribute to it. Thanks!
    Not sure what you mean, but the reason is that water vapor is lighter than air.

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    This is something you really should ask a meteorologist or aeronautical engineer (which I'm not).
    But I know enough that cold air does not hold as much humidity/water vapor as warm air does. That's why when the temperature drops quickly below dew point, the water vapor condenses into mist and fog. Dew point depends on the temperature and humidity and did vary quiet a bit.
    A friend did explain how temperature affected shuttle speed once but I didn't quite understand it. Need to ask doctor Google.

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    I found done info on a pilot training site.

    http://www.pilotfriend.com/training/...g/aft_perf.htm

    Cold air is denser because molecules are more closely packed together and gives shuttles more friction. Hence why we use faster shuttles in cold weather that have less air friction. Apparently High humidity can increase friction as well but not as much as temperature does.

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    Quote Originally Posted by leongwaipak View Post
    I found done info on a pilot training site.

    http://www.pilotfriend.com/training/...g/aft_perf.htm

    Cold air is denser because molecules are more closely packed together and gives shuttles more friction. Hence why we use faster shuttles in cold weather that have less air friction. Apparently High humidity can increase friction as well but not as much as temperature does.
    Engineer here. High humidity does not increase friction on projectiles.

    Higher humidity = faster shuttles. Higher temperature = faster shuttles. Higher altitude = faster shuttles.

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    I did Physics with Space Science and Technology at University many moons ago so I can hopefully explain this, however please bear in mind humidity has a small factor on shuttle speeds compared to temperature and pressure.

    In the 1800s Italian physicist Amadeo Avogadro discovered the law that helped explain why humid air is less dense than dry air. In layman terms, he found that a fixed volume of gas (i.e. one cubic metre) at the same temperature and pressure, would always have the same number of molecules no matter what gas is in the container.

    For example 1 cubic metre of dry air contains about 78% nitrogen molecules (with each having a molecular weight of 28), 21% of oxygen (molecular weight of 32) and 1% other gases which we will ignore as negligible. All molecules are free to move in and out of the 1 cubic metre or air. If we added water vapour molecules to our cubic foot of air, they would displace some of the existing nitrogen and oxygen molecules. Since water vapour has a molecular weight of only 18 (1 oxygen and 2 hydrogen atoms), the density of air decreases. Remember that the total number of molecules must remain the same.

    I hope this helps.

    Kindest regards,

    -Ajay-

    Quote of the Day
    Age is something that doesn't matter, unless you are a cheese.

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    Cool! So, then if the gas is hydrogen (MW=2) and we add in water vapour, the air density will increase.

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    Thanks for the clarification.
    Now it'll probably take me the rest of this year to understand it all. Lol

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