Imagine a 747 sitting on a huge conveyor belt, as wide and as long as the runway. The belt is designed to exactly match the speed of the wheels, moving in the opposite direction.
Can the plane take off?
Can the plane take off?
Please put this to rest for me (argument amongst friends)
- Thread starter Callahad
- Start date
Captain Call
Space Marshal
Lift depends on the air movement over the wings - a plane can lift off standing still if the wind is greater than the require speed to generate takeoff - I have done it in a small plane
Beerjerker
Grand Admiral
I would guess no, since the wings aren't moving through the air.
Maybe @DarthMatter could weigh in. He's studying to be a mad scientist or something like that...
Maybe @DarthMatter could weigh in. He's studying to be a mad scientist or something like that...
exactly my point, the lift is created from the forward motion. apparently theres some mythbuster video proving it wrong, but i think they just made the plane go faster than the treadmill!
CrudeSasquatch
Space Marshal
Must be moving against the wind.
I learned that from sailing.
https://en.wikipedia.org/wiki/Bernoulli's_principle
And grade 7.
I learned that from sailing.
https://en.wikipedia.org/wiki/Bernoulli's_principle
And grade 7.
CrudeSasquatch
Space Marshal
I'm not sure which, your friend or you, is arguing for a treadmill, but the treadmill person is stupid.
Let me put it another way....
If you want to get from New York to London by moonwalking to LA, I will sell you shoes.
Let me put it another way....
If you want to get from New York to London by moonwalking to LA, I will sell you shoes.
Captain Call
Space Marshal
correct -
The movement of air over an airfoil causes the lift – the physical movement forward is not required for takeoff.
Beerjerker
Grand Admiral
So yes it can take off, because the plane will move forward through the air regardless of what the treadmill on the ground is doing?
This question now makes me feel like I smoked weed...
This question now makes me feel like I smoked weed...
Han Burgundy
Space Marshal
This would only be an issue if the airplane was using its wheels to drive its acceleration instead of a prop or turbine. The airplane would only move backwards until its forward thrust overpowered the movement of the treadmill. The plane would then proceed forward as normal and take off fine. I think I saw this question on a HS physics test forever ago.....
Think of the Atmosphere like soup, and the ground as....uh...ground. What the propeller does is pull the plane through the soup by displacing the soup itself, thus not really relying on what is going on with the ground. Am I only making sense to myself? I do that, ya know....
Think of the Atmosphere like soup, and the ground as....uh...ground. What the propeller does is pull the plane through the soup by displacing the soup itself, thus not really relying on what is going on with the ground. Am I only making sense to myself? I do that, ya know....
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the way i understand it is, that the point of the hypothetical treadmill is to keep the plane stationary on the runway with the engines on. so theres no way that would generate upward lift
The engines are thrust based, so baring friction the wheels will just spin faster but the plane will move forward should accelerate to taking off speed.
DarthMatter
Space Marshal
Looks like you guys are handling this fine without me, but I'd love to throw in my thoughts. :)
The plane can't take off standing still, but since the engines "work" on the air and not the ground it doesn't really matter what the wheels are doing, as long as we exclude friction. Excluding friction there won't be any problem with the wheels blowing up and not being able to support the plane either (Unless the wheels rips apart due to internal forces, but I think a treadmill would break down before that and then the question would not work. So lets ignore that).
If we include friction... it boils down to how the friction created from wheels spinning on the ground affects the plane. If the wheels are attached to an engine of some sorts it will create a force on the plane and drag it to a standstill. If the wheels are just ball-bearings on a axel... there isn't really anything that transfers the backwards acceleration of the treadmill from the wheels to the rest of the plane... I'd say the plane accelerates forward with the treadmill trying to keep up with the wheels speed but not really doing anything (kinda like the Mythbusters video above. The plane was faster than the treadmill and took off).
In real life though... something would break. Be it the wheels exploding or the whole landing gear being ripped off the plane ect...
Why this didn't happen to Jamie and Adam is because the car was too slow. The treadmill wasn't fast enough to keep up with the wheels.
This is impossible.
Because the speed of the wheels is the speed of the aircraft added to the speed of the conveyor belt.
Completely correct.
that_frog_kurtis
Space Marshal
omg this stupid retarded shit again.
The plane will go forward on the conveyor belt no matter how fast the conveyor belt is going and will take off. The only thing that will prevent this is the wheel bearings or the wheels/tires themselves fail due to exponential increasing RPM. The plane engine pushes against the air to create forward speed, the wheels just spin freely. FUCK.
The plane will go forward on the conveyor belt no matter how fast the conveyor belt is going and will take off. The only thing that will prevent this is the wheel bearings or the wheels/tires themselves fail due to exponential increasing RPM. The plane engine pushes against the air to create forward speed, the wheels just spin freely. FUCK.
guys the myth buster tackled that probleme
View: https://www.youtube.com/watch?v=YORCk1BN7QY
and prooved that the treadmills just make the wheels spin faster the plane still takes off because the engine push it forward anyone with a few meter of cloth and a remote control plane can test this also there is no engine in plane wheels they are like the front wheel of a bycicle there is no traction at all on the ground so imagine you are on roller skate and you get on a treadmill and your holding yourself in place by holding on side rails with your hands no matter how fast the treadmills go its not harder on you the only thing is the wheel spin faster
and prooved that the treadmills just make the wheels spin faster the plane still takes off because the engine push it forward anyone with a few meter of cloth and a remote control plane can test this also there is no engine in plane wheels they are like the front wheel of a bycicle there is no traction at all on the ground so imagine you are on roller skate and you get on a treadmill and your holding yourself in place by holding on side rails with your hands no matter how fast the treadmills go its not harder on you the only thing is the wheel spin faster
Shadow Reaper
Space Marshal
If the engines exhaust onto the wings as in twin puller configurations, it is possible the wings would have enough lift for takeoff, which would be essentially vertical. This is unlikely, however. If the engines do not push air onto the wings, the plane cannot fly.
have you looked at the video? the propeller plane will fly nothing is preventing the plane from going forward so the wing will get lift same as if the conveyer wasnt even there the only thing it changes is the speed at wich the weels will turn its not the weels that are driving the plane to take off speed
following your logic a floate plane wouldnt take off or a sky plane couldnt take off from the snow ... the weels are just there so the planes doesnt stand on its belly doesnt matter how fast they spin as soon has the propeller exerts more traction then the friction of the weels , skys or float that plane will accelerate and go forward get lift and takeoff no matter what it is standing on
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