stanger00

i dont know shit about physics so i cant make a intelligent answer on why it cant or if it can....

i dont see this happening.

what do you think? this is supposed to air on myth busters tonight but im in germany and have to wait for it to pop up on the internet so i can watch it.

this other forum im on has me flustered about all of this.

sweet 2 k posts...

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JackThe Ripper

anyone who thinks a plane would take off on a treadmill is an idiot.


The plane needs lift to take off.

Lift is achieved by air rushing past it, hitting the wings, which in turn raises the plane through aerodynamics.

A treadmill moves the ground, moving the ground makes no difference, it isnt the GROUND that needs to me moved, it is the air around the plane, or the plane itself.

The only way a plane would take off on a conveyorbelt is if somebody has a giant wind machine working with the belt, however, the conveyerbelt is completely irrellevant, as if you have enough wind you can generate enough lift to get the plane off the ground while it is standing still.



Anyone who does not understand this should stray from aircraft design or any career field that involves physics.


EDIT: Without all the boundaries of the question being explored, i suspect it WOULD be possible for a plane to take off if it was Sitting on a conveyor belt which was moving the plane nose first straight ahead, because then the plane would be pulled forward with the conveyor belt, which would be the same as if pulled under its own power, kind of like a paper airplane being thrown.

But if the question is if the Plane is pointed one direction with the belt moving the other, then no, it wont lift off unless it sticks to the belt and is capable of flying backwards

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HokieStang00

I'll watch it... and then post on here and spoil the answer for you.

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PColav6

rofl

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stanger00

jack that was my argument but this ass hat is saying otherwise.

the plane needs to move forward so it can get some wind under those foils so it can take off.

now a plane will take off on a treadmill but will it take off shorter distance or the same if it were on a tarmac?

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JackThe Ripper

Ok

lets assume the plane needs to be moving at a velocity of 65mph to achieve enough lift to fly.

Also, need to know that wheel movement and plane movement are not the same. Also point of reference is important.

ON TARMAC
Plane facing --->
Plane needs 65 miles per hour to achieve lift.
Wheels moving at rotational rate equivelant to 65mph

ON BELT CONFIG 1
Plane Facing --->
Conveyer moving <---- at 40mph rate
Plane will achieve liftoff when plane reaches 65mph
The wheels will be moving at a rotational rate equivelant to 105mph.

ON BELT CONFIG 2
Plane facing --->
Conveyor moving ----> at 40mph Rate
Plane will achieve liftoff when plane reaches 65mph
The wheels will be moving at a rotational rate equivolant to 25mph.

Nothing changes on these, regardless the plane needs to be moving at 65mph to generate enough lift for take off, speed of the conveyor belt does NOTHING but alter the RPM of the wheels and has NOTHING to do with lift.

The problem is that people are confusing themselves, it is a trick question. People start thinking of the speed of the plane on the Converyor belt....

But that is STUPID because if the conveyer belt is moving ----> and the plane is pointing <---- and the conveyer belt is moving at 60mph, the plane does not stand still when it is moving <---60mph, instead it moves at 120mph from the belts perspective.

They SHOULD be looking at speed of plane VS the viewers perspective which is NOT supposed to be on the conveyer belt.

The conveyer belt ONLY matters to the speed of the wheels, it makes NO difference to lift UNLESS the Plant is attached to the conveyer belt and using it as some sort of slingshot.

The speed of the ground is COMPLETLY IRRELEVANT

it is the movement of AIR that causes lift. And Conveyor belts do NOT move air.


However, if a plane is standing still on a runway, it is possible to blow enough air at it to make it lift.

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JackThe Ripper

if the planes wheels currently roll
60MPH ------>
and the belt moves <------ 60mph
then the plane requires the EXACT same distance to take off, however, the wheel speed (WHICH IS IRRELLEVANT) will be doubled.

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PColav6

You care too much, jack

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stanger00

dude im with you and tracking. i know wheel speed is irrelevant. i just cant believe that people believe this thing will take off from a treadmill its freaking stupid. gawd i feel dumb even making this freakin thread.

its 1 am have to go to work in a few. damn CDC's are due tomorrow 7 level shit. im not clicking on any threads about this till i watch the episode after i get off of work tomorrow.

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stanger00

so whats your opinion about this....

you already know mine. that motherf'n plane is just going to rock back and forth as the treadmill is moving.

now if they add some thrust then the plane will move on its own (overpower the treadmill) and eventually take off and like jack said its going to take off at whatever wind speed it needs for lift off.

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PColav6

It won't take off.

That's my opinion, and it's also the truth.



DA TROOF!

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TJeffer3

+1 on that one. Now we all know that there isnt a treadmill big enough to hold a plane. So y is this even an issue. LOL.

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zigzagg321

why does this question still get asked????

on a tread mill...like the one in the proposed question...only thing moving on that plane is the wheels. plane would be stationary with its wheels spinning.

no forward movement=no lift=no fly.

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foncarelli

I remember when DannyB asked this question.

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JackThe Ripper

I remember when you used to post on here!
Long time no see!

lol

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theponyfactor

It took off with ease. the thing is the plane is not driven by the wheels so propeller will still pull it through the air.

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JackThe Ripper

They must be looking at this differently than what most people i have heared of describing the scenario

The point of a treadmill is to spend the energy of moving forward without actually moving forward. The idea that a plane rolling on a treadmill to where the plane is neither moving forwards or reverse.

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Codiddy

dude the pilot was dumbfounded, even he thought he would just sit there. He said he didn't notice anything different when he took off either. It was cool to watch

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theponyfactor

That was the biggest problem with all the debate over this topic, people had different ideas of how it was going to be done.

Obviously if the plane wasn't moving through the air it wouldn't take off, there would be no lift on the wings.

I think poeple were making it too complicated, they simply were going to put a plane on a treadmill (going the same speed as takeoff in the opposite direction) and take off.

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r3dn3ck

planes don't fit on treadmills.

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Badfish

not again...

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00blkstanggt

What kind of plane are we talking about here? Now if it is a Harrier jet, then I would say yes it can take off.haha

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