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Thread: Okay Krupski or other knowing people answer this please

  1. #61
    Team GunsNet Silver 12/2011 N/A's Avatar

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    You're missing the part that the wheels DO NOT move the plane. All they do is act as roller bearings to remove any friction the plane otherwise would have with the runway.

    The thing that moves the plane is the thrust of the engines, whether in the air or on the run way.

    Or look at it this way. If your car runs out of gas and you have to put it in neutral and push it off the highway, where does the power to move the car come from? You, are the power pushing the car.
    In a plane there is never any power to the wheels. The thrust is added to the whole plane, not the wheels. The wheels are just roller bearrings to allow the plane to move around on solid ground with greatly reduced friction. They work much better than trying to slide a 747 on its belly down the run way.

    If you have a pair of roller skates sitting in the closet, they just sit there as nothing powers the wheels. Put them on and you become the power to move the skates.
    Climbed up on a regular treadmill and you can roller skate to your hearts content.

    True, if you set the treadmill to match your normal speed of skating, you will remain stationary to your coach standing beside you, but if he reaches over and speeds it up, you get dumped off the back. If he slows it down you skate off the front.
    Try all that just scuffing your feet along the treadmill without skates. The skates are the roller bearings that removes the friction between you and the treadmill, nothing more. They have no more power on their own than the planes wheels do.

    "But wait!", you reply, "you said that if the treadmill matched my speed, I would remain stationary?" Yes I did, but that is because you need something to push against to make yourself go forward on skates. That something is turning your feet sideways and using the friction of the skate wheels against the surface to push forward. Without that ability to push off, you couldn't skate.
    In this scenario, the treadmill works against how fast you can keep pushing off, or skating we call it.

    In a plane, no work at all has to be applied to the wheels. All the work is applied to the plane and the wheels just free wheel down the treadmill. The same if you are on skates, just staying stationary with your coach and somebody comes along and gives you a push, a thrust that moves you up a little on the treadmill, even tho the turning of the treadmill and your skate wheels remained the same. To
    Last edited by N/A; 08-30-2019 at 08:27 PM.
    No enemy of America would have ever been killed if they didn't show up to be killed. HDR

  2. #62
    Team Guns Network Silver 04/2013 alismith's Avatar

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    I know the wheels have have nothing to do with moving the plane. Thrust moves the plane. All the wheels do is reduce friction of the plane on the runway. Like you said, it's better than trying to slide the belly of the plane across the runway.

    But, the wheels do increase their speed as the thrust forces the plane to move faster. As the wheels turn faster, so does the treadmill.

    As the wheels move faster because of the applied thrust to the plane, the treadmill moves faster in response to the wheel speed.

    Since the plane must move down the runway to build air pressure on the wings, the wheels allow this to be done easier. However, if the ground (treadmill) is moving at the same speed and in the opposite direction at the same time, doesn't this cause the plane to remain stationary?

    Doesn't this negate any movement forward of the plane through the air?
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  3. #63
    Team Guns Network Silver 04/2013 alismith's Avatar

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    Quote Originally Posted by N/A View Post
    You're missing the part that the wheels DO NOT move the plane. All they do is act as roller bearings to remove any friction the plane otherwise would have with the runway.

    The thing that moves the plane is the thrust of the engines, whether in the air or on the run way.

    Or look at it this way. If your car runs out of gas and you have to put it in neutral and push it off the highway, where does the power to move the car come from? You, are the power pushing the car.
    In a plane there is never any power to the wheels. The thrust is added to the whole plane, not the wheels. The wheels are just roller bearrings to allow the plane to move around on solid ground with greatly reduced friction. They work much better than trying to slide a 747 on its belly down the run way.

    If you have a pair of roller skates sitting in the closet, they just sit there as nothing powers the wheels. Put them on and you become the power to move the skates.
    Climbed up on a regular treadmill and you can roller skate to your hearts content.

    True, if you set the treadmill to match your normal speed of skating, you will remain stationary to your coach standing beside you, but if he reaches over and speeds it up, you get dumped off the back. If he slows it down you skate off the front.
    Try all that just scuffing your feet along the treadmill without skates. The skates are the roller bearings that removes the friction between you and the treadmill, nothing more. They have no more power on their own than the planes wheels do.

    "But wait!", you reply, "you said that if the treadmill matched my speed, I would remain stationary?" Yes I did, but that is because you need something to push against to make yourself go forward on skates. That something is turning your feet sideways and using the friction of the skate wheels against the surface to push forward. Without that ability to push off, you couldn't skate.
    In this scenario, the treadmill works against how fast you can keep pushing off, or skating we call it.

    In a plane, no work at all has to be applied to the wheels. All the work is applied to the plane and the wheels just free wheel down the treadmill. The same if you are on skates, just staying stationary with your coach and somebody comes along and gives you a push, a thrust that moves you up a little on the treadmill, even tho the turning of the treadmill and your skate wheels remained the same. To
    I think I'm starting to get what you're saying about the wheels.

    If I'm understanding you and Krupski correctly, the wheels and treadmill have absolutely nothing to do with the plane gaining takeoff speed.

    The treadmill and wheels are diversions to seeing what's actually happening with the plane. They have no action on the plane, at all.

    The plane will take off just as it normally does if it weren't on a treadmill, but on a regular runway.

    Right?
    "Valar morghulis; valar dohaeris."

    "Never say, "gun control" but instead say, "victim disarmament." - L Neil Smith

    Making good people helpless won't make bad people harmless.

    Freedom isn't free.

    "Attitude is the paintbrush that colors our world." TV Series, Haven.

    My Spirit Animal has rabies.

  4. #64
    Team GunsNet Silver 12/2011 N/A's Avatar

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    Not the way I see it. The wheels act like the gears on the rear differential of a car that allows one wheel to turn faster in a turn. The gears isolate the speed of one wheel from the other.
    The wheels on a plane isolate the plane from the surface speed so it can go faster than the treadmill.

    I wish I knew a good way to explan it to you. If I was Spock, I could give you the Vulcan Mindmeld ...but alas, I didn't serve with Spock, Spock is not a friend of mine, so I'm no Mr. Spock.

    I promise you, if you are sitting on a treadmill like that in a plane, and the Tommy Knockers are coming, give that plane all the power it has and it will take off.
    No enemy of America would have ever been killed if they didn't show up to be killed. HDR

  5. #65
    Team GunsNet Silver 12/2011 N/A's Avatar

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    Quote Originally Posted by alismith View Post
    I think I'm starting to get what you're saying about the wheels.

    If I'm understanding you and Krupski correctly, the wheels and treadmill have absolutely nothing to do with the plane gaining takeoff speed.

    The treadmill and wheels are diversions to seeing what's actually happening with the plane. They have no action on the plane, at all.

    The plane will take off just as it normally does if it weren't on a treadmill, but on a regular runway.

    Right?
    Right!

    You posted this while I was typing the above and didn't see it till just now.
    You're right, it's like magic, focus on the diversion and don't see what the plane is really doing?
    No enemy of America would have ever been killed if they didn't show up to be killed. HDR

  6. #66
    Team Guns Network Silver 04/2013 alismith's Avatar

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    Quote Originally Posted by N/A View Post
    Right!

    You posted this while I was typing the above and didn't see it till just now.
    You're right, it's like magic, focus on the diversion and don't see what the plane is really doing?
    Yup. You need lift and thrust to make a plane fly. The wheels and treadmill don't affect the forces that cause a plane to fly, therefore, the plane will fly.

    I went wrong when I tried to figure how the wheels were being affected by the treadmill. They had nothing to do with the actual take off and flying.

    Got it now. Thanks.
    "Valar morghulis; valar dohaeris."

    "Never say, "gun control" but instead say, "victim disarmament." - L Neil Smith

    Making good people helpless won't make bad people harmless.

    Freedom isn't free.

    "Attitude is the paintbrush that colors our world." TV Series, Haven.

    My Spirit Animal has rabies.

  7. #67
    Team GunsNet Silver 12/2011 N/A's Avatar

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    Here's something I thought of last night trying to fall of asleep. If the tradmill effected the plane as some suggest, and kept it from moving at all .....what would happen to the jet if it came in for a landing on the tradmill?
    Would the moment the wheels touch the treadmill bring it to a screeching halt at the place it first touches down?

    Can you imagine a plane that weighs sevearl thousands of pounds landing at 200 knots coming to an instantaneous stop?
    At the best, I could see all the people come squirting out the cockpit windshield like shelling peas out of a pod.
    At worst.......??????
    No enemy of America would have ever been killed if they didn't show up to be killed. HDR

  8. #68
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    Gatta have lift to get off the ground (airflow over the wings) and thrust to move.
    “The two enemies of the people are criminals and government, so let us tie the second down with the chains of the Constitution so the second will not become the legalized version of the first.”
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  9. #69
    Team GunsNet Silver 12/2011 N/A's Avatar

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    Quote Originally Posted by 5.56NATO View Post
    Gatta have lift to get off the ground (airflow over the wings) and thrust to move.
    That's a given.
    And?
    No enemy of America would have ever been killed if they didn't show up to be killed. HDR

  10. #70
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    Setting a plane on a giant treadmill isn't going to get it into the air?
    “The two enemies of the people are criminals and government, so let us tie the second down with the chains of the Constitution so the second will not become the legalized version of the first.”
    -Thomas Jefferson

  11. #71
    Senior Member Viking350's Avatar

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    The thrust of the jet engines is against the surrounding air, not the treadmill. As N/A made clear to me the wheels are simply roller bearings. Newton’s third law says that for every action there is an equal and opposite reaction. Since the force is the thrust exiting the back of the jet engine the opposite reaction is a force against the entire jet propelling it forward. If it stood still that would violate Newton’s third law.

  12. #72
    Team GunsNet Silver 12/2011 N/A's Avatar

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    Quote Originally Posted by 5.56NATO View Post
    Setting a plane on a giant treadmill isn't going to get it into the air?
    Setting a plane on a runway or a treadmill isn't going to make a difference about getting it in the air ......anymore than landing one on a runway or treadmill is going to make a difference in getting it to land normally.
    No enemy of America would have ever been killed if they didn't show up to be killed. HDR

  13. #73
    Administrator Krupski's Avatar

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    Quote Originally Posted by N/A View Post
    Setting a plane on a runway or a treadmill isn't going to make a difference about getting it in the air ......anymore than landing one on a runway or treadmill is going to make a difference in getting it to land normally.
    What if the pilot runs backwards (from the pilot's seat to the tail)?

  14. #74
    Team GunsNet Platinum 02/2015 davepool's Avatar

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    Quote Originally Posted by Krupski View Post
    What if the pilot runs backwards (from the pilot's seat to the tail)?
    If he was really, really fat the plane's nose would lift up and the plane couldn't take off. I learned everything i know about physics from watching Wiley Coyote and the roadrunner cartoons
    Last edited by davepool; 09-02-2019 at 08:22 AM.

  15. #75
    Senior Member whiskeyman's Avatar

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    Quote Originally Posted by Krupski View Post
    What if the pilot runs backwards (from the pilot's seat to the tail)?
    ‘ʎןqıssod

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