Will it take off?

[MJDub]

Re: Will it take off?

What feather said is exactly right. Airspeed that is higher over the top than the bottom of the wing is what gives a plane lift. A conveyor belt serves no purpose because you need the air over the wings to be at rotation speeds, not just have the wheels move really fast.

[miketpoto]

Re: Will it take off?

Yes it will take off. Think of yourself running on a treadmill. The faster you run the more air resistance you have. IMO

You aren't much of a runner or a thinker, are ya?

[Garrick]

Re: Will it take off?

^ lmao. someone had to say it

[diegoff]

Re: Will it take off?

No I don't think so. You're saying the conveyor cancels out the plane's forward vector. So your plane is stationery.

If I'm not wrong the plane has to gather enough speed for the air/wind to work on those wings to lift it up.



Dynamics of flight

^ the reason why It won´t take off...

[srbbnd]

Re: Will it take off?

Not so my friend. Runner's world suggests always running at a +1% incline to what you would normally do to simulate the MISSSING air resistance.

The only air resistance encounterd while on a treadmill is from your arms swinging through the air...not whole body air resistance from running normally.

The only difference is wind. The air resistance would be the same outside if there was no wind. I think...

[jamesalvarez]

Re: Will it take off?

the aeroplane can still take off, it just needs an adequate runway length treadmill, and its wheels will simply spin twice as fast as normal matching the aeroplanes speed x 2 due to the treadmill (disregarding all friction forces etc).

The thrust comes from jet engines, not from the wheels, if it did then aeroplanes wouldn't be able to fly very far.

Its a funny psychological trick because it has two garden paths:

-One is that due to the conveyer belt, the plane can take off vertically relative to a static observer - wrong
-The other is that it cant take off because the plane can't generate any thrust due to the belt -wrong too.

[Steve Graham]

Re: Will it take off?

^^^ but isnt the point of this being the fact that the plane ISNT moving forward just stationary on a "conveyor belt"? so having a runway length treadmill would defeat the purpose.

[unkownartist]

Re: Will it take off?

I'm with feather, the plane is in fact stationery (conveyor canceling the forward motion of the plane) and you need airspeed to lift the wings/plane. Can't see how the plane took off.

doesnt meen everything around it is stationary i.e. air etc

[jamesalvarez]

Re: Will it take off?

in which case the plane wouldn't be able to take off simply because the runway length is too small, so not enough upward force is generated from airflow to counterat gravity (I guess the problem could be read like that) lol

another way of looking at it is that if you fired wind towards the nose of the plane at a speed that matched the jetengines, the aeroplane then could rise directly up to a static observer

[Kamal]

Re: Will it take off?

doesnt meen everything around it is stationary i.e. air etc

so if you're standing stationary, a wind blows against you, you open your shirt and hold it apart like a set of wings, you're betting you're gonna take off ?

[unkownartist]

Re: Will it take off?

erm tbh it was a bit of a dum answer, crazy question...i,m gonna loose sleep over this one tonight lmao...

[threehills]

Re: Will it take off?

the aeroplane can still take off, it just needs an adequate runway length treadmill, and its wheels will simply spin twice as fast as normal matching the aeroplanes speed x 2 due to the treadmill (disregarding all friction forces etc).

The thrust comes from jet engines, not from the wheels, if it did then aeroplanes wouldn't be able to fly very far.

Its a funny psychological trick because it has two garden paths:

-One is that due to the conveyer belt, the plane can take off vertically relative to a static observer - wrong
-The other is that it cant take off because the plane can't generate any thrust due to the belt -wrong too.

I understand your arguement, I do..really. But the problems states that the conveyor has a system that tracks the speed of the plane and matches it exactly in the opposite direction. I think about it like this...imagine the treadmill starts up fist. Natually the place moves backwards relative to the viewer as the friction between the wheels and treadmill holds the plane fast to the tread. Now the jets fire, providing thrust that is equal to the friction (static initially, kinetic once the wheels start to roll), but opposite in direction. Now, the plane is rolling along the tread, in a "forward" direction, but remaining stationary to the observer (a fixed point on the ground). The obsever/fixed point could also be considered to be the air. So.....relative to the air, the plane is not moving. No air is sliding over the wings and no lift is generated so the plane remains firms on the treadmill.

[miketpoto]

Re: Will it take off?

I understand your arguement, I do..really. But the problems states that the conveyor has a system that tracks the speed of the plane and matches it exactly in the opposite direction. I think about it like this...imagine the treadmill starts up fist. Natually the place moves backwards relative to the viewer as the friction between the wheels and treadmill holds the plane fast to the tread. Now the jets fire, providing thrust that is equal to the friction (static initially, kinetic once the wheels start to roll), but opposite in direction. Now, the plane is rolling along the tread, in a "forward" direction, but remaining stationary to the observer (a fixed point on the ground). The obsever/fixed point could also be considered to be the air. So.....relative to the air, the plane is not moving. No air is sliding over the wings and no lift is generated so the plane remains firms on the treadmill.

Exactly

[thesightless]

Re: Will it take off?

it wont take off. the premise of drag and lift on the wing is absent when the wing is not moving through a medium (air).

the wheels are rotating around thier core, however, there is nothing happening to the wing.

[MJDub]

Re: Will it take off?

Let me bring my piloting expertise into this one (yes I'm a private pilot).

Say you were about to take off and you had a wind that was going parallel to the runway. Conventional wisdom would say that you would want to take off with the wind, no? But conventional wisdom doesn't apply to aerodynamics. You want to take off into the wind (a headwind) because air resistance is what gets the airplane off the ground. Since there is more wind/air coming over the leading edge of the wing (i.e. what creates lift), even though you're technically not going as fast with relation to ground speed, the air speed is all that matters. So if you were to takeoff with the wind (a tailwind), you would need to be going much faster ground speed wise to get the same amount of air over the leading edge of the wings, and unless you're taking off on the space shuttle landing strip, you would probably run out of runway before you got to rotation speed (speed the airplane can lift off the ground and climb).

So going back to this "conveyor belt" idea, there is no way that this would work with any conventional aircraft because while your wheels may be spinning like you're going 150 knots, your airspeed is essentially 0. The engine does provide some air over the wings (in a propeller plane for example) but nowhere near the amount and speed of air that is needed to get the plane off the ground. You need forward motion.