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Evanade
Rionnag Alba Triumvirate.
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Posted - 2008.09.10 13:35:00 -
[121]
It's just that depending on the way the problem is interpreted both answers are correct. --------------------------- sok alt - main got banzored |
P'uck
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Posted - 2008.09.10 13:40:00 -
[122]
So please, explain how the plane would not take off.
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Kaeten
Hybrid Syndicate
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Posted - 2008.09.10 13:42:00 -
[123]
Originally by: Evanade It's just that depending on the way the problem is interpreted both answers are correct.
thing is the plane is moving through the air, moving forward through the air cause the propeller is making it ove forward, if it was a car it would sit like a duck because gravity+wheels is whats making it stay put, however the planes wheels are freerolling.
A thing that helped me very much, the planes wheels spine DOUBLE as fast as if it was a cars wheels. ________________________ I'M POOR
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Evanade
Rionnag Alba Triumvirate.
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Posted - 2008.09.10 13:54:00 -
[124]
Originally by: P'uck So please, explain how the plane would not take off.
When i first read it (and that was really really long ago) i thought they simply meant 'any wing shaped object on wheels on a conveyor belt, moving at the same speed as the belt, so effectively standing still'
I was like 12 at the time.
Obviously if it's a real aircraft and normal thrust is applied, it will take of, albeit slightly slower as the wheels generate more friction due to turning faster to compensate for the belt under them. --------------------------- sok alt - main got banzored |
Dionisius
Gallente Vagabundos
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Posted - 2008.09.10 13:59:00 -
[125]
Edited by: Dionisius on 10/09/2008 14:07:26 Hmm eventually the plane will take off, now the question is, how long it will stay in the air, or in simpler words, if its feasable with lets say... an A330 for instance.
And the question that can be made is also, will the tires withstand the aditional fatigue and pressure?
Another thing, this is what probably confusing people, the plane needs to have a certain amount of ground speed, this is what is going to make the necessary air intake into the plane engines in order for it to develop more thrust and achieve the much needed air speed ( in very rough terms ), then its aerodinamics work and the wing geometry combined with the speed aquired + engines that will keep the plane in the air. ( again rougly put )
In a convoyor or something belt, the plane does not achieve ground speed the regular way, its solely thrust work performed by the engines BUT without the airflow trough the wings that is given when the plane is in a regular airstrip, in other words, the plane will eventually pick up enough trust and " air speed " for an initial push and thus that is were my question stands, it will take off, but will it have enough airflow to keep it in flight?
Also @ the person that compared the belt to the carrier, the carrier catapult actually pushes the planes forward in order for these to pick up enough ground speed and airflow around the wings for it to get airborn, in fact if you notice the pilots that take off an carrier have to push the engines to maximum trust and even then when the plane leaves the deck it kinda, falls for a second and gets elevated, this is due to the airflow that is acquired during the push combined with the catapult and engine trust.
Sorry but my english isn't that good for more techical terms and i hope i made myself clear on my doubts about the plane of akita's initial question residing in flight. _____________________________________
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P'uck
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Posted - 2008.09.10 14:04:00 -
[126]
Edited by: P''uck on 10/09/2008 14:05:32 The whole thing is supposed to be an exercise in relativity. There is some weird wording of the problem that COULD enable you to argue, that the speed of the conveyor ramps up to infinite, making the whole riddle impossible.
Everything the conveyor does is MATCH THE SPEED OF THE PLANE. (it does NOT counter the wheelspin but the movement of the plane relative to the solid ground).
So the conveyor and the wheels are probably spinning at about double liftoff speed, which really isnt THAT fast for most planes, now is it?
edit: also, if you start to argue in THAT direction, youre a tw@t. to quote that cern guy. because you probably understand the riddle and just try to make it complicated. or do you really want to have all the friction properties listed when the riddle is told?
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Dionisius
Gallente Vagabundos
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Posted - 2008.09.10 14:09:00 -
[127]
Originally by: P'uck Edited by: P''uck on 10/09/2008 14:05:32 The whole thing is supposed to be an exercise in relativity. There is some weird wording of the problem that COULD enable you to argue, that the speed of the conveyor ramps up to infinite, making the whole riddle impossible.
Everything the conveyor does is MATCH THE SPEED OF THE PLANE. (it does NOT counter the wheelspin but the movement of the plane relative to the solid ground).
So the conveyor and the wheels are probably spinning at about double liftoff speed, which really isnt THAT fast for most planes, now is it?
edit: also, if you start to argue in THAT direction, youre a tw@t. to quote that cern guy. because you probably understand the riddle and just try to make it complicated. or do you really want to have all the friction properties listed when the riddle is told?
if that was directed to me then look at above post for clarification. : )
FTR i work in an airline ( IT dept ). _____________________________________
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P'uck
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Posted - 2008.09.10 14:12:00 -
[128]
Edited by: P''uck on 10/09/2008 14:12:48
Originally by: Dionisius ... the plane does not achieve ground speed the regular way, its solely thrust work performed by the engines BUT without the airflow trough the wings that is given when the plane is in a regular airstrip
a) this is wrong.
Originally by: Dionisius FTR i work in an airline ( IT dept ).
b) what has this got to do with anything are you building aerodynamic laptops?
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Dionisius
Gallente Vagabundos
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Posted - 2008.09.10 14:16:00 -
[129]
Originally by: P'uck Edited by: P''uck on 10/09/2008 14:12:48
Originally by: Dionisius ... the plane does not achieve ground speed the regular way, its solely thrust work performed by the engines BUT without the airflow trough the wings that is given when the plane is in a regular airstrip
a) this is wrong.
Originally by: Dionisius FTR i work in an airline ( IT dept ).
b) what has this got to do with anything are you building aerodynamic laptops?
Explain how it is wrong then.
I wasn't even considering that the ground speed is 0, ya know with 0 ground speed unless we are talking about a V-TOL plane you can't take off safely. : ) _____________________________________
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P'uck
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Posted - 2008.09.10 14:24:00 -
[130]
Edited by: P''uck on 10/09/2008 14:25:45 Apart from the impossibility to build a conveyor that large and smooth it really doesnt matter what kind of plane you put there (unless its a magic plane that accelerates with its wheels).
And I wont explain why its wrong, sorry, it has been covered on the last pages about a hundred times. Short version: It accelerates and creates lift just like a plane on a normal runway. You can, in fact, completely ignore the conveyor. Everything that counts is the speed relative to the AIR. and the effect of the conveyor on the air around the wings is neglectable. If we assume it would do ANYTHING it would probably HELP in taking off, since the air would be moving around in exactly the direction we need it, if we want to create lift.
oh btw: I cba to explain it any further, if THIS doesnt help, NOTHING will
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Dionisius
Gallente Vagabundos
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Posted - 2008.09.10 14:43:00 -
[131]
Edited by: Dionisius on 10/09/2008 14:45:32
Originally by: P'uck Edited by: P''uck on 10/09/2008 14:25:45 Apart from the impossibility to build a conveyor that large and smooth it really doesnt matter what kind of plane you put there (unless its a magic plane that accelerates with its wheels).
And I wont explain why its wrong, sorry, it has been covered on the last pages about a hundred times. Short version: It accelerates and creates lift just like a plane on a normal runway. You can, in fact, completely ignore the conveyor. Everything that counts is the speed relative to the AIR. and the effect of the conveyor on the air around the wings is neglectable. If we assume it would do ANYTHING it would probably HELP in taking off, since the air would be moving around in exactly the direction we need it, if we want to create lift.
oh btw: I cba to explain it any further, if THIS doesnt help, NOTHING will
Taken from the website:
" In this case an aircraft is moving rather swiftly relative to the ground at the time a severe wind shift occurs, this being most dangerous when the aircraft is taking off or landing. Though movement over the ground never ceases the movement of the air relative to the wing - in this case a headwind becoming a tail wind - causes the aircraft to crash because the air over the wing is suddenly not of sufficient velocity or airspeed to generate the lift needed to keep it airborne. This also explains why aircraft have airspeed indicators used to accurately measure ôairspeedö. Without it an aircraft cannot fly. The aircraft on the conveyor generates no airspeed though its propulsion system manages to keep it stationary on the conveyor and therefore cannot fly.
I've been a pilot for over thirty years and am currently employed by a nationally recognized air carrier. "
LINKAGE!!!
There ya go, the man is partly right.
You need lift and airspeed to be achieved.
My doubt stands, it may " take off " but will it remain in the air?
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Straight Chillen
Gallente Solar Wind
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Posted - 2008.09.10 15:10:00 -
[132]
I dont see how moving on a conveyor belt provides a sufficient airstream to reduce enough pressure on the topside of the wing to create lift.
Depending on your frame of refernce, such as an observer to the side, the plane would be stationary. As its not moving foward, it's not moving through the air, and as such its not getting any lift. So no, your plane would stay grounded.
Now if the conveyor belt is moving the air too, thats a different scenario.
Bernoulli's Principal Simplified _
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Karentaki
Gallente Fighting While Intoxicated Intrepid Crossing
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Posted - 2008.09.10 15:10:00 -
[133]
This thread seriously needs some good hard science:
Assuming the tyres have perfect grip on the runway/conveyer belt, and air resistance is negligible.
m = mass of plane k = coefficient of friction on wheel bearings T = thrust from plane engines
in order for the plane to accelerate:
T>kmg
if this is true, then the plane will take off, otherwise it won't. Simple.
Quote:
EVE is like a sandbox with landmines. Deal with it.
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Reven Cordelle
Caldari School of Applied Knowledge
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Posted - 2008.09.10 15:21:00 -
[134]
Simple way of looking at it since people still aren't getting it...
If you put a skateboard on a treadmill and tie a rope to it, set the treadmill to max speed and pull the skateboard towards you even slowly, will the skateboard move toward you?
Yes.
Now replace the skateboard with a plane and the rope with air that the plane uses to gain its thrust and you have your answer. The plane will still move regardless of being on a conveyor, thus it'll still take off.
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Dionisius
Gallente Vagabundos
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Posted - 2008.09.10 15:29:00 -
[135]
Originally by: Reven Cordelle Simple way of looking at it since people still aren't getting it...
If you put a skateboard on a treadmill and tie a rope to it, set the treadmill to max speed and pull the skateboard towards you even slowly, will the skateboard move toward you?
Yes.
Now replace the skateboard with a plane and the rope with air that the plane uses to gain its thrust and you have your answer. The plane will still move regardless of being on a conveyor, thus it'll still take off.
A plane is not a skateboard, it needs something to lift it, in this case air, is the air moving trough the wings at enough speed for them to sustain the plain in air?
If yes then the plane takes off.
If not then the plane does not take off.
And thats my question, does the conveyor generate enough airspeed around the plane so that it actually lifts? _____________________________________
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Howzic
Caritas.
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Posted - 2008.09.10 15:40:00 -
[136]
Christ people (those that believe it won't take off). Maybe a different scenario will work. You're in an ultra-long pool and as you start swimming forward, the bottom of the pool matches your speed the opposite way. Will you move forward? (I'll give you a hint. The answer is yes) The bottom of the pool could move 20X's your speed in the opposite direction and you'd still move forward.
Taking that to the airplane example. The water beneath you is your wheels, your arms are the planes props, pulling through the water or air around you. You move forward.
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Sharupak
Minmatar Brutor tribe
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Posted - 2008.09.10 16:28:00 -
[137]
Originally by: Howzic Christ people (those that believe it won't take off). Maybe a different scenario will work. You're in an ultra-long pool and as you start swimming forward, the bottom of the pool matches your speed the opposite way. Will you move forward? (I'll give you a hint. The answer is yes) The bottom of the pool could move 20X's your speed in the opposite direction and you'd still move forward.
Taking that to the airplane example. The water beneath you is your wheels, your arms are the planes props, pulling through the water or air around you. You move forward.
nuh uh! The bottom of the pool would move fast enough to cause current just strong enough in the opposite direction to cancel your foward swimming motion! _______________________________________________ RuntimeError: ChainEvent is blocking by design, but you're block trapped. You have'll have to find some alternative means to do Your Thing, dude. |
Lori Carlyle
Aztec Industry
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Posted - 2008.09.10 16:34:00 -
[138]
Sounds like a job got Garrys mod tbh
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Reven Cordelle
Caldari School of Applied Knowledge
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Posted - 2008.09.10 16:52:00 -
[139]
Originally by: Dionisius
A plane is not a skateboard, it needs something to lift it, in this case air, is the air moving trough the wings at enough speed for them to sustain the plain in air?
If yes then the plane takes off.
If not then the plane does not take off.
And thats my question, does the conveyor generate enough airspeed around the plane so that it actually lifts?
Okay, lets rewind.
How do you suppose a plane, when taxiing, moves along the ground?
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kor anon
Amarr Sons Of The Fallen BROTHERS GRIM.
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Posted - 2008.09.10 16:58:00 -
[140]
Yes it can as even though the plane is not moving, the thrust forward is still provided.
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Suze'Rain
Caldari
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Posted - 2008.09.10 17:12:00 -
[141]
Originally by: Dionisius
A plane is not a skateboard, it needs something to lift it, in this case air, is the air moving trough the wings at enough speed for them to sustain the plain in air?
If yes then the plane takes off.
If not then the plane does not take off.
And thats my question, does the conveyor generate enough airspeed around the plane so that it actually lifts?
Head. Desk.
Since when did treadmills create a windtunnel that forces the airflow to move? oh, hang on... they dont, do they? so a treadmill has no effect on airspeed.
Aircraft engines push/pull/power an aircraft forwards by thrust. this is'nt driven through wheels (a torque force), but directed into the body structure. therefore an aircraft moves forward irrespective of the speed of ground beneath it.
to prevent an aircraft taking off, you would need to fit some sort of infinately powerful fan behind the aircraft, to blow air forwards, so there was no air flowing over the wings.
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Jonathan Calvert
Minmatar Empire Mining and Trade
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Posted - 2008.09.10 17:13:00 -
[142]
Oddly enough if you do a search, this topic comes up every 6 months. And the end result is that the plane either takes off or doesnt depending on how you phrase the question. The simplest argument is that if you put a plane on a moving treadmill, it will take off, because the wheels freely spin. There is no friction. Case closed.
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P'uck
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Posted - 2008.09.10 17:26:00 -
[143]
Originally by: Dionisius The aircraft on the conveyor generates no airspeed though its propulsion system manages to keep it stationary on the conveyor and therefore cannot fly.
I've been a pilot for over thirty years and am currently employed by a nationally recognized air carrier.
The guy who said that may or may not be employed on an air carrier. Cleaning up shit and vomit (those are very important tasks I dont want to ridicule in any way, but they dont have much to do with aerodynamics) is also somethint that can get you a job on a carrier, you know.
Anyways, what he said is simply rubbish At least this part. He starts off with some remotely related stuff about the change in air currents near the ground but after thats right where he took a sharp turn in the direction of candyland fiction.
I dont know why I still fall for this, I believe you just try to get me to do Cpt. Obvious, but wtf, at least that's a stylish superhero, so here goes:
If you want to put it this way, the propulsion system of the aircraft is linked to the (stationary) air around it, not to the conveyor. everything the conveyor does, is spin the wheels of the plane, which DO NOT generate enough friction to influence our little exercise.
WE'RE NOT TRYING TO TAKE OFF IN A CAR FFS.
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Vabjekf
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Posted - 2008.09.10 18:08:00 -
[144]
Edited by: Vabjekf on 10/09/2008 18:13:24
Originally by: Dionisius
Originally by: Reven Cordelle Simple way of looking at it since people still aren't getting it...
If you put a skateboard on a treadmill and tie a rope to it, set the treadmill to max speed and pull the skateboard towards you even slowly, will the skateboard move toward you?
Yes.
Now replace the skateboard with a plane and the rope with air that the plane uses to gain its thrust and you have your answer. The plane will still move regardless of being on a conveyor, thus it'll still take off.
A plane is not a skateboard, it needs something to lift it, in this case air, is the air moving trough the wings at enough speed for them to sustain the plain in air?
If yes then the plane takes off.
If not then the plane does not take off.
And thats my question, does the conveyor generate enough airspeed around the plane so that it actually lifts?
The conveyor is not generating airspeed, the fact that the plane is moving forward through space is what is generating the airspeed. All the conveyor does is make the wheels spin faster because while the plane is moving forward the ground is moving backwards (instead of the plane moving forward and the ground staying in place).
There is no difference between a plane on a conveyor belt vs a plane on a runway, other than the plane on the conveyor belt's wheels have to spin faster. Thats IT. ONLY DIFFERENCE. It does not need to do anything extra special to take off as normal, it may need to add just a tad more thrust to overcome the friction in the wheels, but thats it. The plane moves forward in SPACE because the conveyor belt is not capable of effecting the planes location in space forcefully enough because forces of the belt are almost totally countered by the wheels.
That is the answer to the problem. As ive said you guys are trying to overcomplicate it. You jump too far ahead before you actualy consider the question that is being asked in the first place!.
The answer is that because the way an aircraft propels itself, a conveyor belt does not actually have much of an effect on a plane that happens to be on top of it! So the plane can just ignore it. It does not CARE if its on a conveyor belt or not. It will take off like normal, because a conveyor belt is NOT CAPABLE of keeping an aircraft from going forward and generating lift and taking off.
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NanDe YaNen
The Funkalistic
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Posted - 2008.09.10 18:12:00 -
[145]
Originally by: Straight Chillen I dont see how moving on a conveyor belt provides a sufficient airstream to reduce enough pressure on the topside of the wing to create lift.
Depending on your frame of refernce, such as an observer to the side, the plane would be stationary. As its not moving foward, it's not moving through the air, and as such its not getting any lift. So no, your plane would stay grounded.
Now if the conveyor belt is moving the air too, thats a different scenario.
Bernoulli's Principal Simplified
I will from here forth link to this post every time I want to discredit your input on any subject. ---------------------------------------
Originally by: Red Raider A happy gamer isnt on the forums, they are playing the game unless they have an idea that they honestly think is helping out.
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P'uck
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Posted - 2008.09.10 18:28:00 -
[146]
Oh and something else:
This question should be a part of the process you have to go through to get a pilot's license. EVERYWHERE in the world. Just for the sole purpose of us not having to deal with pretend pilots in discussions about the subject.
Well, at least I thought basic knowledge about first grader physics are somewhat required for flying a plane, but hey, maybe I'm wrong.
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Abrazzar
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Posted - 2008.09.10 18:45:00 -
[147]
Heh, with enough thrust the plane will accelerate, no matter if it has contact with the ground in the first place. Then, if the conveyor belt only needs to be long enough to allow the plane to take off and not crash and slide on the ground, it'll reach enough speed to lift off.
To proof this by experiment, blow up an air balloon and let it fly. Same principle.
-------- Ideas for: Mining
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Pwett
Minmatar QUANT Corp. QUANT Hegemony
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Posted - 2008.09.10 18:49:00 -
[148]
The answer is no:
Planes can't stand. Q.E.D. debate is null. _______________ Pwett CEO, Founder, & Executor <Q> QUANT Hegemony
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Sharupak
Minmatar Brutor tribe
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Posted - 2008.09.10 18:50:00 -
[149]
Originally by: P'uck Oh and something else:
This question should be a part of the process you have to go through to get a pilot's license. EVERYWHERE in the world. Just for the sole purpose of us not having to deal with pretend pilots in discussions about the subject.
Well, at least I thought basic knowledge about first grader physics are somewhat required for flying a plane, but hey, maybe I'm wrong.
_______________________________________________ RuntimeError: ChainEvent is blocking by design, but you're block trapped. You have'll have to find some alternative means to do Your Thing, dude. |
Dionisius
Gallente Vagabundos
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Posted - 2008.09.10 19:32:00 -
[150]
Edited by: Dionisius on 10/09/2008 19:48:01 If the plane and ground speed are matched the plane does not move period! Notice the question dummies
" An airplane is standing on a (very/sufficiently) long, powerful and fast conveyor belt. The airplane pilot attempts to take off moving forward. The controller of the conveyor belt is making the conveyor belt move in the opposite direction with the same speed. Can the plane take off, yes or no ? "
Both speeds are matched! If you have V0 condition you aren't at proper speed to take off look at the freaking picture Akita posted - > PICTURE
And for the genius stating that the engines propel the plane, true, now your assumption is on a normal strip, take the example and you don't have enough attrition for that you have to generate more power in order to move the plane forward, which is not the case.
Second, the belt itself does not generate enough airflow to cause the sustenance needed to lift the plane, which is for a plane to take off.
And p'uk or puke... lol @ you , seriously.
Edit: For more clearance
The plane gets its lift via the Bernoulli effect.
This has to do with wing shape and its interaction with air moving rapidly past.
If the plane has no motion relative to the wind, there will be no lift to force the plane up.
I think thats the clearer my English can be for the moment :P _____________________________________
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