Aces High Bulletin Board
General Forums => The O' Club => Topic started by: Curlew on May 14, 2010, 04:21:03 PM
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(http://graphics8.nytimes.com/images/2006/12/11/technology/poguespan.jpg)
Some argue that the aircraft would not be able to lift off if it was on a treadmill because the treadmill would match its speed. Im not a fan of that theory, have my own, but for all of your sake DISCUSS!!!!!!
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it would because the wheels aren't the pushing back.
thank you mythbusters :rock
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it would because the wheels aren't the pushing back.
thank you mythbusters :rock
The truck they used stopped matching the speed of the plane at some point....therefore the test proves nothing!
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SO IT BEGINS!!!!!! muahahahahahaha!!!!! :devil
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it would because the wheels aren't the pushing back.
thank you mythbusters :rock
Unless you subscribe to the rotational momentum theory. If the treadmill's acceleration rate is unlimited, it could add enough energy in the opposite direction to stop the airplane. (It takes energy to make a wheel roll) Of course, "unlimited" does not exist in nature, so any "real world" plane will take off.
T
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The plane's wings cannot fit through the treadmill! It would break the wings! end of discussion
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NO!
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The thrust does not come from the wheels, so it matters not how fast the treadmill goes, if the plane rotates at 150mph, the wheels will just be going at the speed of the treadmill +150mph when it lifts off. The plane will still move forward and lift off normally.
Now somebody else recently posted helicopter on a turntable. That's a better one. :noid
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Unless you subscribe to the rotational momentum theory. If the treadmill's acceleration rate is unlimited, it could add enough energy in the opposite direction to stop the airplane. (It takes energy to make a wheel roll) Of course, "unlimited" does not exist in nature, so any "real world" plane will take off.
T
No it couldn't, the axles would fail long before enough force is exerted. To say that the treadmill can accelerate infinitely to counteract forward motion just creates a feedback loop that results in the destruction of the wheels/bearings/axles. That's the only way a treadmill could stop it from flying.
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but for all of your sake DISCUSS!!!!!!
Again? I think pretty much all arguments and theories have been posted in this 400+ thread: http://bbs.hitechcreations.com/smf/index.php/topic,225421.0.html ;)
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for pete sake picture it without wheels sitting on the tread mill...........
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Oh god, not again....
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Now somebody else recently posted helicopter on a turntable. That's a better one. :noid
(http://postworthy.com/contributorimages/helicoptor-will-it-take-off.jpg)
New topic!!!!!
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LMAO...I guess you have to assume the engines are running... :lol
Think aircraft carrier here fellas...but in this case one that is going really fast doesn't matter how fast the treadmill is spinning the wheels...as soon as engins produces proper thrust to produce lift, the plane will take off.
As for the helicopter, it will fly but not for long...by the time it lifts the pressure off that turntable, it will be out of control and crash.
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If you ignore friction, the treadmill is incapable of stopping the aircraft. If you consider friction, the landing gear burns up and the plane falls into the treadmill and promptly gets flung violently backwards, killing everyone.
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LMAO...I guess you have to assume the engines are running... :lol
Think aircraft carrier here fellas...but in this case one that is going really fast doesn't matter how fast the treadmill is spinning the wheels...as soon as engins produces proper thrust to produce lift, the plane will take off.
As for the helicopter, it will fly but not for long...by the time it lifts the pressure off that turntable, it will be out of control and crash.
Engine thrust doesnt produce lift, they produce forward speed which makes the air flow over the wings to produce lift. a plane on a tread mill that matches wheel speed instantly, will never move forward to produce airflow over the wings, so it will not takeoff.
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Engine thrust doesnt produce lift, they produce forward speed which makes the air flow over the wings to produce lift. a plane on a tread mill that matches wheel speed instantly, will never move forward to produce airflow over the wings, so it will not takeoff.
You are correct but do you know why?
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This is beyond stupid.
The only relevant factor is airspeed; the speed of air over the wings. That creates lift. The speed relative to the ground, treadmill, universe etc. is completely irrelevant.
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This is beyond stupid.
The only relevant factor is airspeed; the speed of air over the wings. That creates lift. The speed relative to the ground, treadmill, universe etc. is completely irrelevant.
You're wrong.
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No.
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No.
Yes.
I've found that most of the people who don't get it typically believe that they are so smart that they don't have to think about it. It's not that simple.
*I will add that the owner and developer of this game agrees that the plane won't fly.
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The only relevant factor is airspeed. If the plane is unable to generate sufficient airspeed to take of... for whatever reason... it will fail to take off. If it manages to generate sufficient airspeed it will take off. You may argue any hypothetical scenario you want, but it will always boil down to airspeed.
The original poster suggested "the aircraft would not be able to lift off if it was on a treadmill because the treadmill would match its speed." That means that if the aircraft was travelling at 100 mph the treadmill would spin at 100 mph in the opposite direction. The wheels of the aircraft would thus be rotating at 200 mph. The airspeed would still be 100 mph and if that is sufficient the aircraft would take off. You may argue that the landing gear would fail or any other hypothetical scenario, but it ultimately boils down to airspeed.
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It depends if the treadmill is matching the plane's speed or the wheel's speed...
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The original poster said "aircraft".
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If the treadmill is matching the plane's speed then it will take off without a problem. The treadmill might add ten feet to its roll.
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What you are suggesting is that the treadmill matches the planes acceleration with roll resistance. So if the plane's engines generate 100 lbs of thrust the treadmill counters with 100 lbs worth of resistance. Completely different scenario.
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What you are suggesting is that the treadmill matches the planes acceleration with roll resistance. So if the plane's engines generate 100 lbs of thrust the treadmill counters with 100 lbs worth of resistance. Completely different scenario.
So... You agree that the plane won't take off. That was easy.
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The original poster said "speed" not "acceleration", so the answer is "no". I don't agree.
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IF... It's MATCHING its speed its MATCHING its acceleration...
The distinction is whether it's matching the wheel's speed or the plane's speed.
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Wow this is so dumb.. The power of an airplanes engines are not transfered to the ground like a car.. It's power to the air causing forward momentum and "airspeed" no matter what's happening underneath the aircraft itself (minus the force of friction).. The airplane will takeoff but the wheels will be spinning faster.. What is so difficult about this for people to understand?
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Wow this is so dumb.. The power of an airplanes engines are not transfered to the ground like a car.. It's power to the air causing forward momentum and "airspeed" no matter what's happening underneath the aircraft itself (minus the force of friction).. The airplane will takeoff but the wheels will be spinning faster.. What is so difficult about this for people to understand?
http://bbs.hitechcreations.com/smf/index.php/topic,289123.msg3672572.html#msg3672572
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IF... It's MATCHING its speed its MATCHING its acceleration...
The distinction is whether it's matching the wheel's speed or the plane's speed.
No, it's not. The original poster said "the aircraft would not be able to lift off if it was on a treadmill because the treadmill would match its speed". If the aircraft is travelling at a speed of 100 mph the wheels are rotating at 100 mph at their circumference (duh!). Thus the treadmill is "matching" the speed by rotating at 100 mph in the opposite direction. If the treadmill matches the wheel speed, as in a runaway process where any initial input results in an infinite feedback loop, then the argument is, as I said, beyond stupid.
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If the treadmill matches the wheel speed, as in a runaway process where any initial input results in an infinite feedback loop, then the argument is, as I said, beyond stupid.
So we agree that the plane won't fly. Brilliant.
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No we don't agree, because this thread is not about your hypothesis, but the original poster's: "the aircraft would not be able to lift off if it was on a treadmill because the treadmill would match its speed"
As you said: "The treadmill might add ten feet to its roll."
Case closed.
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No we don't agree, because this thread is not about your hypothesis, but the original poster's: "the aircraft would not be able to lift off if it was on a treadmill because the treadmill would match its speed"
As you said: "The treadmill might add ten feet to its roll."
Case closed.
The only relevant factor is airspeed; the speed of air over the wings. That creates lift. The speed relative to the ground, treadmill, universe etc. is completely irrelevant.
So... You disagree with yourself... This is something you'll have to work out on your own.
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Heres Your Answer To This Myth
http://www.straightdope.com/columns/read/2638/an-airplane-taxies-in-one-direction-on-a-moving-conveyor-belt-going-the-opposite-direction-can-the-plane-take-off (http://www.straightdope.com/columns/read/2638/an-airplane-taxies-in-one-direction-on-a-moving-conveyor-belt-going-the-opposite-direction-can-the-plane-take-off)
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So... You disagree with yourself... This is something you'll have to work out on your own.
Nope. You're just being ( I hope for your sake) deliberately obtuse, and a poor loser. Read BowHTR link and take it gracefully why don't you.
"...Soon the foolish have persuaded themselves that the treadmill must operate at infinite speed. Nonsense. "
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Taking friction out of the picture, the plane would lift off normally. Air flowing over the airplane's wings is not dependent on ground speed.
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If you ignore friction, the treadmill is incapable of stopping the aircraft. If you consider friction, the landing gear burns up and the plane falls into the treadmill and promptly gets flung violently backwards, killing everyone.
I considered friction, but isn't the treadmill subject to the laws of physics as well, doesn't it have some giant motor and bearings/bushings.
I figure the motor/bearings on any conveyor that large, would burn out long before the wheel bearings/tires any a Boeing or Airbus would.
Airplane wins: THE END :aok
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We did this recently... again. http://bbs.hitechcreations.com/smf/index.php/topic,281455.0.html (http://bbs.hitechcreations.com/smf/index.php/topic,281455.0.html)
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Are any of you really so ignorant (or stupid) of the reasons aircraft fly as to think that really, a treadmill would have any effect on a plane taking off? Wheel speed is totally irrelevant. I honestly hope this consideration/argument is all tongue-in-cheek.
The jet engine, or in the case of a propeller driven aircraft, the prop, move the aircraft forward in relation to the air, and when the aircraft moves forward against the wind, the wings create lift, and with enough wind created will generate enough lift to overcome the weight of the aircraft. Wheel speed in irrelevant, with skis and floats doesn't matter.
Ever see a good STOL aircraft takeoff? With sufficient wind down the runway, and correct flap down settings, a STOL plane can takeoff with virtually no forward speed, it's all about wind over the wings.
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If the treadmill is rolling fast enough, the cohesion of the air with it will induce enough airspeed on the wings to generate a lift vector strong enough to lift the plane up... that's fact, that's science!
No seriously, I still can't believe this myth even exists, if it ain't for a massive worldwide failed joke. Its made for those people that get hands on flight controls for the first time and wonder why the plane rolls instead of turning horizontal like a road car when they yank the aileron controls.
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Are any of you really so ignorant (or stupid) of the reasons aircraft fly as to think that really, a treadmill would have any effect on a plane taking off? Wheel speed is totally irrelevant. I honestly hope this consideration/argument is all tongue-in-cheek.
The jet engine, or in the case of a propeller driven aircraft, the prop, move the aircraft forward in relation to the air, and when the aircraft moves forward against the wind, the wings create lift, and with enough wind created will generate enough lift to overcome the weight of the aircraft. Wheel speed in irrelevant, with skis and floats doesn't matter.
Ever see a good STOL aircraft takeoff? With sufficient wind down the runway, and correct flap down settings, a STOL plane can takeoff with virtually no forward speed, it's all about wind over the wings.
No, I don't think anyone here is that stupid. I think the argument by those against (and it is valid) is that if the conveyor where able to roll fast enough that it would melt/destroy the wheel bearings and tires of the aircraft before the aircraft reached rotate speed.
Imagine the treadmill goes up to 1,000 mph. Discounting all wheel friction, of course the plane would still move forward and lift off, but if rotate speed is say 150mph. The landing gear wheels will be spinning at 1,150mph. Now bring wheel friction back into the equation. If those wheels failed at only 500mph, then like Boilerdown said the aircraft would only reach maybe 50mph forward speed before the gear wheels got destroyed and the aircraft belly lands on a conveyor going 450mph and gets flung violently backwards.
I however reject that on the premise that the conveyor at that speeds would fail before the aircraft's wheels would.
I find this:
(http://postworthy.com/contributorimages/helicoptor-will-it-take-off.jpg)
much more of a mental challenge. If the turntable matched the speed of the rotors in the opposite direction. Then it seems to be the rotors would just be sitting still generating no lift. Not to mention the pilot would become some kind of gooey ooze on the inside of the windscreen spinning very fast.
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While we are at it lets put a fan on our sail boat to make it go faster. :lol
http://answers.yahoo.com/question/index?qid=20080506234729AApZqDe
http://www.youtube.com/watch?v=0CrXvOKPymk
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(http://www.dawanowens.com/blog/wp-content/uploads/2009/10/eye-poke.jpg)
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what is the relative speed of a treadmill tossed out a window while the tread spins 100mph in reverse :huh
This thread has got to be the dumbest ever :rofl :bolt:
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What about a hovercraft on a giant cattle grid??
(http://upload.wikimedia.org/wikipedia/commons/1/18/Cattle_grid_(scotland)_close_up.jpeg)
(http://www.cse.nd.edu/~dthain/courses/cse341/spring2005/projects/www/hovercraft.jpg)
:noid
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While we are at it lets put a fan on our sail boat to make it go faster. :lol
http://answers.yahoo.com/question/index?qid=20080506234729AApZqDe
http://www.youtube.com/watch?v=0CrXvOKPymk
lmfao
i read that and laughed for about 2 mins and dont know why lol. then watched the video. I actually didnt think the "boat" would move. if i wanted too i could think it out but dont really want too. instead will think out the helicopter one.
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While we are at it lets put a fan on our sail boat to make it go faster. :lol
http://answers.yahoo.com/question/index?qid=20080506234729AApZqDe
http://www.youtube.com/watch?v=0CrXvOKPymk
I will admit that I posted this thread as an almost trolling joke, but this i actually can speak on, I have been sailing for many years, and have been teaching sailing for 6 years now, The yahoo answers are an absolute joke, mostly cause they never once recognize a sail as a airfoil WHICH IT IS
(http://img15.imageshack.us/img15/7583/sailforcediagram.jpg)
the diagram above shows the forces at work in a sailboats movement, air passing over the sail creates lift like a wing heading in the direction of the red arrow, this force can be divided into two vectors as shown by the blue arrows labeled A and B, Force A is negated by the keel underneath the ship as shown with a green arrow. If the force of the green arrow negates the force of arrow A then only arrow B's force remains thus producing forward motion through the lift of an airfoil. If the keel did not exist all sailboats would travel in the direction of red arrow. With that said producing a greater force in direction of the wind would produce greater lift that could be easily negated by the keel in the water. But to make this work you would have to place the fan at an angle to the ship as a wind force coming directly on the bow of the ship would produce a red arrow that runs perpendicular to the ship and therefor be completely negated by the green arrow.
(http://img541.imageshack.us/img541/1216/sailforcediagramwithfan.jpg)
So if we add a fan into the equation, as shown here, we can see that the force of the air from the fan is shown in purple pushing backwards should have 2 effects, one shown in light purple is the vectors of the increase in force of the sail due to increased airflow, and once again the force perpendicular to the ship is negated, The second is the force produced by the fan pulling air like a propeller would shown in yellow, and once more we devide the force into vectors shown in light yellow, and of course the perpendicular force is eliminated by the keel. Notice how with both the light purple and light yellow arrows pointing in the direction of boats travel are not negated. and therefor indicate an increase in speed.
None of the yahoo answers mentioned this and the video supposedly "proving" the concept doesn't even use a sail, just a flat area for the wind to blow and that is not how a sail works, but it does prove that a parachute in a zero g environment could be pushed by a fan held by the user in the direction of the fan.
As for the hovercraft, now thats funny, and idk, ill have to ponder that one
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Is it possible for a B17 to back-up under its own power? The answer is yes. But how?
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Back to the airplane/conveyor belt issue.
Here's a wrench to toss in. :P
http://www.fanwing.com/pix.htm (http://www.fanwing.com/pix.htm)
creates it's own lift :aok
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Is it possible for a B17 to back-up under its own power? The answer is yes. But how?
using independant engines and wheel brakes to walk backwards step by step?
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Mythbusters tested it... it worked..with a real plane...
right here.
http://www.youtube.com/watch?v=YORCk1BN7QY&feature=related
-BigBOBCH
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Easy way to prove it, put a toy car on a treadmill. Simulate engine thrust by pushing on the back of the car. It moves forward.
Plane may not take off unless the treadmill is as long as a runway but the motion under the free spinning wheels has nothing to do with it. Unless the wheels come off due to increased spin.
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No, the plane needs the lift by movement.
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What about a hovercraft on a giant cattle grid??
(http://upload.wikimedia.org/wikipedia/commons/1/18/Cattle_grid_(scotland)_close_up.jpeg)
(http://www.cse.nd.edu/~dthain/courses/cse341/spring2005/projects/www/hovercraft.jpg)
:noid
I've seen demonstrations where one goes over telephone poles spaced about 3-4 feet apart and they didn't roll, so I'll assume that the flat tops of the cattle grid would provide enough surface area to keep it afloat.
Edit: And no, the plane will not take off without enough forward movement to provide the necessary lift.
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The treadmill only causes the free spinning wheels to spin faster and does not act against forward motion unless the propulsion comes from the gearing of the wheels, therefore the plane gets forward motion to create the lift.
If you push on the toy car like a jet engine would push on the plane will it not move forward?
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Easy way to prove it, put a toy car on a treadmill.
right
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I will admit that I posted this thread as an almost trolling joke, but this i actually can speak on, I have been sailing for many years, and have been teaching sailing for 6 years now, The yahoo answers are an absolute joke, mostly cause they never once recognize a sail as a airfoil WHICH IT IS
Beat me to it -- absolutely speeds up the boat. In that youtube flick the paper is basically a really inefficient spinnaker, but with a real spinnaker you are still treating it as an airfoil. Whereas the main fore/aft sail is creating leeward and forward motion, the spinnaker is angled in such a way to create lift with the force vectors pointed forward and up. Hence, by creating this vertical airfoil up front, you can move faster than the wind when it is at your back.
Hovercraft - I don't believe it would work, particularly going over that deep of a pit. If the pit were more shallow, (and therefore had less air to pressurize in order to maintain the pocket) perhaps that would make a difference. I'd imagine it would be a mighty messy splatter either way. :lol I'm not entirely sure on this one though.
Helicopter - No idea, but the image is hilarious.
Plane - Biiiiiig old face palm.
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The Myth can't be tested in real life guys. It makes a hidden claim that is violated the moment the aircraft moves forward.
You cant maintain the same wheel speed and move forward at the same time. As soon as the plane moves forward you can no longer match the exact speed of the treadmill.
It violates the law of non- contradiction.
However the plane will take off as tested by the myth busters. But you will never be able to match the wheel speed as soon as it mover forward.
Ask youself match the wheel speed "compared to what"?