Poll: Mythbusters - Will the plane take off?

but but, what if the treadmill goes 10,000,000,000,000,000 miles an hour and they only use a piper cub to test it? :sarcasm:
 
Trick question...because you know if it doesn't take off, they'll find a way to make it takeoff and/or explode :)
 
If anyone can show me any math that shows the plane will take off, I would gladly take a look.


But this is such a simple topic, and I cannot understand why this topic comes up, and many people actually believe the treadmill will help in some way.
With the treadmill moving backwards at 60kts (relative to the air), and a C-172 moving forward at 60kts (relative to the treadmill), the velocity of the C-172 is 0kts relative to the wind. No air over the wings, and lift = Cl*.5*rho*v^2*s, when V=0, lift = 0, the plane does not fly.

Simple. End of story. Plane on a treadmill does no good. Plane will not fly. Period.
 
aerospacepilot said:
If anyone can show me any math that shows the plane will take off, I would gladly take a look.


But this is such a simple topic, and I cannot understand why this topic comes up, and many people actually believe the treadmill will help in some way.
With the treadmill moving backwards at 60kts (relative to the air), and a C-172 moving forward at 60kts (relative to the treadmill), the velocity of the C-172 is 0kts relative to the wind. No air over the wings, and lift = Cl*.5*rho*v^2*s, when V=0, lift = 0, the plane does not fly.

Simple. End of story. Plane on a treadmill does no good. Plane will not fly. Period.
Click to expand...


I'm going to try to explain...I used to think exactly that. But then I realized that the speed of the treadmill is irrelevant. The thrust is created by the propeller - NOT the wheels. Therefore, the wheels will simply spin at twice the speed of the treadmill. The propeller will propel the airplane forward across the treadmill. Air will begin to flow over the wings as the plane begins to move across the treadmill. Eventually, the airplane will reach Vr. This is assuming the airplane doesn't reach the front of the treadmill and fall off.
 
aerospacepilot said:
If anyone can show me any math that shows the plane will take off, I would gladly take a look.


But this is such a simple topic, and I cannot understand why this topic comes up, and many people actually believe the treadmill will help in some way.
With the treadmill moving backwards at 60kts (relative to the air), and a C-172 moving forward at 60kts (relative to the treadmill), the velocity of the C-172 is 0kts relative to the wind. No air over the wings, and lift = Cl*.5*rho*v^2*s, when V=0, lift = 0, the plane does not fly.

Simple. End of story. Plane on a treadmill does no good. Plane will not fly. Period.
Click to expand...

:banghead::banghead::banghead::banghead::banghead::banghead:

The wheels of the plane are in contact with the treadmill which is moving backwards at 60 knots. However, the wheels of the airplane do not provide the force that propels the aircraft forward. The propeller does. The prop will spin to move the plane forward at 60 knots. The speed of the aircraft is 60 knots, but the speed of the wheels is 120 knots (forward speed of the aircraft plus the reverse speed of the treadmill). Because the wheels do not provide the force to propel the aircraft forward, the prop only has to overcome the drag in the wheel bearings, which is virtually nothing.

Imagine this: you tie a string to the front of a model airplane and place it on a treadmill. You start the treadmill and hold the string to keep the plane from moving backwards. The wheels spin on the airplane because the treadmill is moving backwards, but you are keeping the plane stationary by holding the string. Now, you start to walk away from the treadmill while holding the string. The plane will roll as you walk away, despite the fact that the treadmill is moving backwards. The spinning propeller on a real airplane acts the same as the string on the model airplane in this example. It is providing the force to propel the aircraft forward, not the wheels.
 
If the plane is in a static environment I don't see how it could take off. Now if the plane is gonna move forward in the treadmill than that's another story.
 
In their experiment, it will take off.
But only cause they ###### it up.

I doubt they'll test it as accurately as they would need to in order to get a conclusive answer.
 
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