Brain Teaser

Discussion in 'Off Topic' started by csmguitarman, Oct 25, 2007.

  1. csmguitarman

    csmguitarman New Member

    Joined:
    Sep 8, 2007
    Messages:
    321
    Likes Received:
    0
    I came up with the question. how do you think it got all over the internet. Proof? the whole damn internet is littered with it. find me proof on the internet to back up your side of the story
  2. csmguitarman

    csmguitarman New Member

    Joined:
    Sep 8, 2007
    Messages:
    321
    Likes Received:
    0
    no it is not like a cars burnout because the wheels are hooked to a drivetrain. that is why they are spinning. Tell me the the last time you have seen a plane do a burnout. and no the planes engines dont make it float. they make it move. and yes it is regardless that the planes wheel have contact with the ground because they dont make the plane move forward they just let the plane roll along while the engines pull the plane trough the air

    instead of just assuming you are right try thinking about what you are reading. you might actually understand. i came up with the question based on my knowledge about the answer. please just allow me to explain the correct answer and stop subbing in your own theories. Ask the others on here that posted "oh yeah now i get it" they all used to think the plane didnt take off and now do. Are you seeing a trend. Dont worry my little friend youll get it. Would you argue with your math teacher if you though that 2+2=5 just to be right or would you want them to explain why 2+2=4
  3. csmguitarman

    csmguitarman New Member

    Joined:
    Sep 8, 2007
    Messages:
    321
    Likes Received:
    0
    lift is for take off. and how does a plane take off? by reaching take off speed. and how does it reach take off speed? by pulling its self through the air. and what is take off? the point at which a plane is pulling its self through the air fast enough to overcome gravity. and what is gravity? well its the reason a plane needs free spinning wheels so it doesnt drag across the ground while it is trying to take off. and what is take off.............Oh no now I've gone cross eyed...........
  4. MBK2

    MBK2 New Member

    Joined:
    Sep 8, 2007
    Messages:
    2,553
    Likes Received:
    0
    I can see that you aren't going to be able to see the concept of lift, which is airflow over and under the wings. And despite the plane's engines pushing the plane thru the air, it has to roll 'first' to get up to the required speeds to have enough airflow over/under the wings for the lift, and since you are now saying that the treadmills speed 'ISN'T' matching the speed the plane starts rolling while you first stated that it would (which would have kept the plane stationary because not enough speed would keep the plane too heavy to get the lift needed to get it to start lifting off the ground at which point the thrust of the jet engines would have propelled the plane to continue to fly thru the air as you're thinking)

    Since you can't grasp the concept of flight it is useless for me to explain any further. I just don't care to waste any more time explaining aeronautic physics to you.......
    Let's just leave it at 'We agree to disagree' OK ?? Ciao
  5. csmguitarman

    csmguitarman New Member

    Joined:
    Sep 8, 2007
    Messages:
    321
    Likes Received:
    0
    OMG. What grade are you in. THE PLANE WILL MOVE FORWARD LIKE NORMAL.

    When did i say that the treadmill isnt matching speed.

    Think of this What makes a planes wheels move. There is not direct drive system. The plane pulling itsself along the ground. THE ONLY WAY THE TREADMILL MOVES IS WHEN IT IS MATCHING THE SPEED OF THE PLANE. SO IF THE PLANE IS NOT MOVING HOW IS THE TREADMILL MOVING?

    Since i cannot grasp the concept of flight. I am an aeronautical engineer major. Gimmie a break.

    Please watch this.
    http://video.google.com/videoplay?d...=11&start=0&num=10&so=0&type=search&plindex=0
  6. csmguitarman

    csmguitarman New Member

    Joined:
    Sep 8, 2007
    Messages:
    321
    Likes Received:
    0
    BTW i am not agreeing to disagree. I will agree that you are stubborn. This question was created around the knowledge of the answer. I am trying to explain the correct answer to you. Please understand that you are thinking of a plane like a car.

    What if i put wheels under a jet ski and put a treadmill just under the water.
    The jet ski would still move forward because it pulls it self through water and needs no assistance in acceleration from its wheel.
    This is the same with the plane. A planes engines take air from in front of them and move it to the back of them.
    How woulda plane with skis take off from snow or water. Those planes dont have wheels. Planes just need something to reduce the friction between them and the ground so the engines can pull the plane fast enough to creat lift and take off
  7. MBK2

    MBK2 New Member

    Joined:
    Sep 8, 2007
    Messages:
    2,553
    Likes Received:
    0
    An aeronautical engineer major!?!? ...Either that's pure BS or you're one of the worst students that that college ever had...LOL

    My brother is an Air Force Flight Instructor. You know, the guy that trains our Air Force Fighter Pilots... He is laughing right now.

    Here, from a pilot in one of your 'all over the internet' threads...

    http://www.askmehelpdesk.com/aviation/would-plane-take-off-141359.html#post670081

    I'm done....sorry, I just don't care anymore what you can't or can grasp...:2cool:

    Ciao
  8. MBK2

    MBK2 New Member

    Joined:
    Sep 8, 2007
    Messages:
    2,553
    Likes Received:
    0

    Ummmmmmm...They're sliding thru the water or snow on skis???....Ummmmm, did I get it right??
    What if the water was a river going 400 mph in the other direction and the plane is a prop plane that is generating 400 mph prop speed...will it take off???


    What you're trying to say is that you can have the plane sit in one place and rev up the jet engines to simulate the thrust of 180 mph...then just let go and the plane will get airborne immediately...see how ludicrous that sounds??

    Again you are talking as if the plane is already airborn. The plane can't fly thru the air until it gets airborn. The plane can't get airborn until in first rolls on the ground to get up to takeoff speed. Take off speeds are needed to create lift. Lift can only happen when the there is enough speed to create enough airflow under the wings.

    OK I'm done for real now...LOL
    Have a Good One...
  9. Der Alta

    Der Alta New Member

    Joined:
    Aug 7, 2007
    Messages:
    2,742
    Likes Received:
    0
    MBK2, a boost in rep for you for staying calm through this discussion. I'd like to continue this discussino as it bears merit and is quite interesting.

    The quote above is perhaps the best analogy to work from. Two scenarios with you pushing the car. One, you are standing behind it on the conveyor and Two, you are standing behind it, at the very end of the belt on the ground.

    In scenario One, I will absolutely agree that the car will go nowhere. Any force exerted on the car by you, is a result of you pushing between the car and the belt. As you push forward, the belt moves in reverse, thus the car goes no where.

    In scenario Two, the car will move. The force you are exerting against the car, is on the ground and not on the belt. Therefore the car has to move forward.

    Now, we expand upon this theory, the car straddles a a strip of ground and there are two conveyor belts, side by side. Albeit attached to the same gearing under ground. (that's simply for the purpose of matching the belts identically). Instead of pushing the car for the few steps in scenario Two before hitting the belt, you can push this car up to your maximum speed.

    This is the same situation for the plane, because the propeller is pushing on the air, which is independent of the belt.
    You've excluded wind speed in the above statement.

    Yes, the plane would. Because the wind speed is zero. In your statement above, inorder for the plane to be stationary, the wind speed would have to be 400mph to keep the plane in one place. If the wind is moving by the prop at 400mph, its also moving by the wings. Thus we have liftoff.

    If the air/wind is moving at less than 400mph, the plane is moving forward at the difference. 300mph wind + 100mph forward movement = 400mph prop speed. 500mph wind + 100 in reverse = 400mph.

    Now, if the plane only had an outboard motor and it used that to get to airborne, with propellor in the water, the wind speed would be irrelevant. If the water speed was matched to the propellor speed, you'd go nowhere.

    I don't think anyont has touched upon the paradox of this situation. The belt and tires will always be in conflict. The plane moves forward an inch, the blet moves in reverse an inch. The tires of the plane have essentially moved two inches. The belt will have to move two inches. It's this paradox that confuses peoples thought process. Once you grasp the tires/belt paradox, it becomes clearer.

    Please MBK2, I'd like to continue the discussion, as it really is engaging and thought provoking.
  10. MBK2

    MBK2 New Member

    Joined:
    Sep 8, 2007
    Messages:
    2,553
    Likes Received:
    0
    Hopefully I can discuss this without you getting upset as guitarman seemed to be getting. I understand though, he's just frustrated because he is truly convinced that what he's thinking is true.

    As for your comment about 400 mph 'wind speed'...where did that come from??
    Also, if the plane rolls forward 1 inch and the treadmill rolls back 1 inch...the planes wheels did not roll 2 inches...it is 2 inches from the starting point on the treadmill but it onlt rolled 1 inch.

    Let me try another scenario...

    I have a camera focused on the center of a plane on a runway, a runway which is a giant treadmill.
    The planes jet engine starts up and tries to push the plane forward 1 foot, but the treadmill rolls back 1 foot. So essentially the plane is still in focus of the camera, right or no? So basically it stayed in place didn't it? No?

    This would happen even if the plane tries to roll the plane forward 100 mph and the treadmill goes in reverse 100 mph, wouldn't it or not?

    So considering that the plane basically stays at the same spot, where would the airflow come from thru the wings to provide the lift?

    Now if you say that the plane's engines eventuallly out-push the treadmills reverse speed, then you may have a case.

    And if you say to me the plane is free-floating and not rolling on the treadmill to begin with, then you have a case.

    But the fact is that, despite the jets' engines trying to push the plane forward using the thrust of wind thru it's turbines, it 'MUST' roll along the ground first to get up to speed to get the airflow required for lift. Then the planes thrust can take over and propell the jet thru the air irrelavent of any contact to the treadmill. But as it stands, it is rolling on the ground first, thus contacting the treadmill.

    Saying that the wheels are freerolling whereas a cars engine has a drivetrain is the wrong thinking.
    A car's engone and drivetrain is the 'propelling' force...just as the jets engine thrusting air is the 'propelling' force.

    If you put a jet engine on a car (so the car has no drivetrain but rsther is propelled by air), and thrust it forward to 180 mph (not even on a treadmill), will it take off??
  11. MBK2

    MBK2 New Member

    Joined:
    Sep 8, 2007
    Messages:
    2,553
    Likes Received:
    0
    BTW...csmguitarman's link to the google video is kinda funny if it's supposed to prove that the plane can still take off. It only proves that you can propelll the plane to roll faster forward than the treadmill is going in reverse. They have the treadmill set to 10 mph 'fixed', but if they have the plane 'fixed' to only roll forward 10 mph...it would stay in the same spot and wouldn't be able to take off because there is no airflow under the wings....
  12. csmguitarman

    csmguitarman New Member

    Joined:
    Sep 8, 2007
    Messages:
    321
    Likes Received:
    0
    Um nope the plane moves forward.

    When a plane is in flight how does it move trough the air. By that i mean what makes it move forward.

    The relationship of a planes engines and the air is the same as a cars to the ground.

    A plane pulls it self through the air no matter if it is on the ground or in the air. The wheels on a plane are there to make pulling itself along the ground easier.

    Agreed?
  13. csmguitarman

    csmguitarman New Member

    Joined:
    Sep 8, 2007
    Messages:
    321
    Likes Received:
    0
    If you actually listen to them, they have the treadmill moving faster than the plane can accelerate. The plane in that video does not all of the sudden start traveling at its top speed.....it has to accelerate up to it.
  14. MBK2

    MBK2 New Member

    Joined:
    Sep 8, 2007
    Messages:
    2,553
    Likes Received:
    0
    At this point it's useless to continue this dicussion because you keep thinking that the plane immediately 'floats' thru the air regardless of gravity and contact to the treadmill. You're talking of a Harrier Jet .
    BTW, if you are basing your theory on that google video, then I can't win this debate against you......ROFLMAO... :tounge:

    Have a good one.....:wink:
  15. csmguitarman

    csmguitarman New Member

    Joined:
    Sep 8, 2007
    Messages:
    321
    Likes Received:
    0
    im sorry if i led you to believe that i though the plane floated. I am merely saying that since the wheels are not attached to a drivetrain, that if you turned the treadmill on the wheels would just spin the speed of the treadmill. Now if you add a force independent of the relationship between the treadmill and the free spinning wheels to the plane. the plane will move forward. I am not basing my theory on the video i am using it as support.

    Sorry if i have acted as if i was angry its just that you have been my most difficult convert. lol

    If you will allow me to have a question an answer session with you and after that you dont see my point then we can let things be.

    Regardless of ground contact how does a plane move forward?
  16. MBK2

    MBK2 New Member

    Joined:
    Sep 8, 2007
    Messages:
    2,553
    Likes Received:
    0
    If the planes' wheels are free wheeling (with no drivetrain) and you turn the treadmill on...the plane would be pushed off the other end of the treadmill. Thus the thrust of the jet engines are what propells it forward to be able to roll at the speed generated by the treadmill.
    The Plane MUST roll on the ground first to get up the speed to take off.

    What you're trying to say is that the planes thrust eventually out-pushes the treadmill....which would basically make this whole question moot.

    I understand you got frustrated and am glad you seem calmer now.
    But regardless, I think we can debate this for the next year and won't agree...:tounge:
  17. csmguitarman

    csmguitarman New Member

    Joined:
    Sep 8, 2007
    Messages:
    321
    Likes Received:
    0
    answer my question though.

    How does a plane move forward whether it is in the air or on the ground.
    Are you saying that the plane accelerates differently on the ground than in the air.
  18. MBK2

    MBK2 New Member

    Joined:
    Sep 8, 2007
    Messages:
    2,553
    Likes Received:
    0
    The plane moves forward because of it's jet engine.....rolling on the ground first...and then flying thru the air after take-off...

    You seem to be saying that the plane rolls on the treadmill on it's own without the thrust of the plane's engine.

    You're comparison of the car's drivetrain and the jets propulsion is only different after the plane gets up enough speed to get OFF the treadmill.
    A car rolls forward on a treadmill because it is propelled forward by it's engine & drivetrain...A plane rolls forward on the treadmill because it is propelled forward by it's jet engine.
    ****No engine & drivetrain on the car, the car rolls off the treadmill backwards.
    ****No Jet engine on the plane, the plane rolls off the treadmill backwards.
  19. MBK2

    MBK2 New Member

    Joined:
    Sep 8, 2007
    Messages:
    2,553
    Likes Received:
    0
    I got another good example .....

    I'm running forward to get a kite airborn... once I get enough speed, the kite gets the lift and flies upward...

    Now, I'm running on a treadmill and trying to run forward, but the treadmill matches the speed I try to generate...so I'm basically running in place.
    Will the kite get airborn??
  20. csmguitarman

    csmguitarman New Member

    Joined:
    Sep 8, 2007
    Messages:
    321
    Likes Received:
    0
    no offense but a poor example. the reason the kite doesnt take off is because you are the power for its acceleration. your transfer of energy from your legs to the ground makes you move forward. the plane doesnt transfer its energy to the ground. It does to the air.

    Take your example and hypothetically add a propeller to the kite. you will run in place and the kite will "fly" away from you.

    You are still treatimg the plane like a car.

    A plane doesnt apply acceleration to its wheel the way a car does.

Share This Page