[JRuckas]

i found this on another site and it got alot of people chatting...

"On a day with absolutely calm wind, a plane is standing on a runway that can move (some sort of band conveyor). The plane moves in one direction, while the conveyor moves in the opposite direction. The conveyor has a control system that tracks the plane speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction). Can the airplane ever take off?"

[JRuckas]

where are the science weenies at

[White99stang]

nope, its needs air underneath the wings of at least 140 to take off, its going to be standing still. I know its different but when your car is on the dyno going 120 stand in front of it, is there any wind resistance, hell no.

[ckthecerealkiller]

What if the conveyor belt is making enough wind spinning so fast. Have you ever stood next to a big conveyor moving really fast there is plenty of wind coming from the belt.

[Twist 2 Go]

where's all the technos at from the earth forum post.. Or the mythbusters??? Will this thread see 20K hits?

[JRuckas]

Originally Posted by Twist 2 Go where's all the technos at from the earth forum post.. Or the mythbusters??? Will this thread see 20K hits?

i was hoping to get some responses from them as well.. someone post it over at the shout website.. i still haven't signed up yet. i will when i get home though.

[artisan00]

its not gonna go anywhere. regardless of how fast the conveyor goes.

and to comment on the post that said something about the wind generated by the conveyor?---- to take off, you need faster moving air *above* the wings. so if anything, the conveyor 'wind' would just generate downforce... remember, faster air above wing -> lower pressure above wing-> lift.

[turp]

No lift=No fly

The airplane does not have sufficient pressure from airflow underneath the wing to decrease the pressure above the wing thus creating lift and raising the plane into the air. If there is no wind there is no kinetic potential of force over and under the wing to lift the plane.

[sAJ1420]

exactly, ive been studying this shit in engineering for months, it needs the wind above and below the wings to create the right amount of lift underneath without making to much that it goes higher and not enough so that it starts falling. That plane would never take off, unless it had vertical thrusters underneath.

[artisan00]

Originally Posted by slo2go No lift=No fly The airplane does not have sufficient pressure from airflow underneath the wing to decrease the pressure above the wing thus creating lift and raising the plane into the air. If there is no wind there is no kinetic potential of force over and under the wing to lift the plane.

the bit there about "pressure from airflow underneath the wing to decrease the pressure above the wing" doesnt make 100% sense, but close enough
its about the low pressure region formed above the wing by the faster moving air. the reason the air moves faster (in a typical situation) is related to the fact that the top of the wing (the curved part) is longer than the bottom (or at least thats what they say when they try and explain this stuff in physics class...)
but i think thats what you were saying, maybe?

Originally Posted by sAJ1420 exactly, ive been studying this shit in engineering for months, it needs the wind above and below the wings to create the right amount of lift underneath without making to much that it goes higher and not enough so that it starts falling. That plane would never take off, unless it had vertical thrusters underneath.

at first, you DO want it to "go higher"...
but basically, yeah...

ps, i also studied the stuff in physics... took 2 years of it in HS and 2 semsters in college, im happy i remember this stuff

[99mustang232]

actually the only thing that would be moving is the plane's wheels and the conveyor, the plane would appear to be standing still, kinda like running on a treadmill.

[sAJ1420]

exactly, its impossible

[Bill]

yeah its not going anywhere. i guess you can think of trying going up the escalator at the mall. if your trying to go up the escalator at the same speed the escalator is going down and you keep moving you'll basically just be in the same spot.

[AtlanticBlue99]

not going anywhere but nowhere and thats all i got to say about that hoe

[99mustang232]

didn't say if the plane was a vertical take off plane?

[AtlanticBlue99]

it isnt, trust me

[sAJ1420]

no someone really probably thought this would work, plus, lets say somehow the treadmill did make enough wind to give the plane lift, where would the plane go once it was out of the wind? nowhere.

[turp]

Originally Posted by artisan00 Originally Posted by slo2go No lift=No fly The airplane does not have sufficient pressure from airflow underneath the wing to decrease the pressure above the wing thus creating lift and raising the plane into the air. If there is no wind there is no kinetic potential of force over and under the wing to lift the plane. the bit there about "pressure from airflow underneath the wing to decrease the pressure above the wing" doesnt make 100% sense, but close enough its about the low pressure region formed above the wing by the faster moving air. the reason the air moves faster (in a typical situation) is related to the fact that the top of the wing (the curved part) is longer than the bottom (or at least thats what they say when they try and explain this stuff in physics class...) but i think thats what you were saying, maybe?

When you LOWER the pressure in an area(above the wing) That is also considered (say it with me class) DECREASING the pressure. I worked on F-14's for 13 years and it is called a decrease in pressure generating lift from air traveling faster over the top of the wing than the bottom.

[artisan00]

Originally Posted by slo2go Originally Posted by artisan00 Originally Posted by slo2go No lift=No fly The airplane does not have sufficient pressure from airflow underneath the wing to decrease the pressure above the wing thus creating lift and raising the plane into the air. If there is no wind there is no kinetic potential of force over and under the wing to lift the plane. the bit there about "pressure from airflow underneath the wing to decrease the pressure above the wing" doesnt make 100% sense, but close enough its about the low pressure region formed above the wing by the faster moving air. the reason the air moves faster (in a typical situation) is related to the fact that the top of the wing (the curved part) is longer than the bottom (or at least thats what they say when they try and explain this stuff in physics class...) but i think thats what you were saying, maybe? When you LOWER the pressure in an area(above the wing) That is also considered (say it with me class) DECREASING the pressure. I worked on F-14's for 13 years and it is called a decrease in pressure generating lift from air traveling faster over the top of the wing than the bottom.

hey man, we are agreeing with each other... all i was pointing out was the sentence "pressure from airflow underneath the wing to decrease the pressure above the wing" looked like it was establishing a cause effect relationship where the pressure from air under the wing was the REASON for the decrease above.... but cleary from your last post you understand the idea so lets shake hands and make up
:wink

[turp]

Y would we need to shake hands? Are you angry? I just pointed out that (for a redneck) I am NOT clueless. I am a pretty fart smeller from time to time.