[So]The Airplane is going to take off...
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don't you think they are going to have to use an RC plane though?
and NGFM is right, they aren't going to be able to replicate anything worthwhile with them...
F the mythbusters, someone who writes computer software for commercial flight simulators has to get off their butt.
and NGFM is right, they aren't going to be able to replicate anything worthwhile with them...
F the mythbusters, someone who writes computer software for commercial flight simulators has to get off their butt.
You (or your brother) have all the major important bits wrong.
When you are on a treadmill running you are using your feet and friction to move forward in relation to the belt. An aircraft is not like a car, it's wheels just freely spin under it as the engines pull air in and thrust it out the back that's where the force is. (Your brother might be a pilot but that does not make him an expert in how things work, a little old lady can drive a car but can she take tell you how a transmission works?)
The thing that people don't understand and what causes all the confusion and threads like these is, it's extremely important how you word the question.
Some wording makes the treadmill match the speed of the plane. Some says it reacts to what the speed of the plane will be at liftoff. Some don't put a limit on it, meaning the treadmill could push up to the speed of light trying to match with and hold back the plane (by spinning it's wheels)
In that last case the plane won't take off simply because the landing gear would fail and it would crumple onto the treadmill.
But in most "normal" versions of the question where the treadmill is limited to going no faster than the take off speed of the plane. The plane would move forward at a normal pace and the wheels would spin under it exactly twice as fast as they would normally spin.
If it helps think about the aircraft as an F-22 instead of a 737.
I get what you are saying. Is anyone factoring in the weight of the plane on the landing gear which then transfers to the wheel bearings which transfers to the free spinning wheels which tranfers to the treadmill.
A plane with free spinning wheels that is not using thrust sitting on a treadmill will be pulled off the back due to gravity which is creating friction between the belt and the free spining wheels which is then transferred to the bearings in those free spinning wheels.
ugh i can't believe i'm going to type all this out but there is a simple way to test it
put a plane on a treadmill, any plane that has a decent amount of weight to it, a remote control plane would work.
what you then do is build a device that prevents the plane from sliding off the treadmill when the treadmill is turned on (this will make the wheels start to spin). We're not going to turn the plane on.
now you have the plane being pushed back against the blocking device with its wheels spinning but not falling off the treadmill. you make a way for the blocking device to measure how much weight in pounds is being pushed against it, this would actually be really simple.
heres a mock drawing
After you see how much backwards force is being pushed by the plane, you could test it at different speeds too and graph it, I imagine you'd get a linear graph.
Now here the tricky part, the original question said the treadmill would match the speed of the plane. I guarantee you when you open the engines to 50% power and say you're going 300 mph, and the treadmill matches that speed, you'll be getting a SHITLOAD more forward thrust than you will be getting backwards momentum from the treadmill.
Mind you like 99% of people know this already, it's that 1% that will never believe it can take off
put a plane on a treadmill, any plane that has a decent amount of weight to it, a remote control plane would work.
what you then do is build a device that prevents the plane from sliding off the treadmill when the treadmill is turned on (this will make the wheels start to spin). We're not going to turn the plane on.
now you have the plane being pushed back against the blocking device with its wheels spinning but not falling off the treadmill. you make a way for the blocking device to measure how much weight in pounds is being pushed against it, this would actually be really simple.
heres a mock drawing
After you see how much backwards force is being pushed by the plane, you could test it at different speeds too and graph it, I imagine you'd get a linear graph.
Now here the tricky part, the original question said the treadmill would match the speed of the plane. I guarantee you when you open the engines to 50% power and say you're going 300 mph, and the treadmill matches that speed, you'll be getting a SHITLOAD more forward thrust than you will be getting backwards momentum from the treadmill.
Mind you like 99% of people know this already, it's that 1% that will never believe it can take off
I get what you are saying. Is anyone factoring in the weight of the plane on the landing gear which then transfers to the wheel bearings which transfers to the free spinning wheels which tranfers to the treadmill.
A plane with free spinning wheels that is not using thrust sitting on a treadmill will be pulled off the back due to gravity which is creating friction between the belt and the free spining wheels which is then transferred to the bearings in those free spinning wheels.
See my post.
I'm amazed at the ignorance, too.
Are we talking real plane that needs runway space to take off? or are we talking cox model airplane stuff that takes off and hovers just on engine pull...
If real single engine airplane, like a Bananza V tail, then that thing is not taking off with only the engines wind power "flowing" over its wings... I don't care if the wheels are spinning as fast as they need to go in order to usually gain lift off... no air from forward momentum over wings means plane no fliy
If real single engine airplane, like a Bananza V tail, then that thing is not taking off with only the engines wind power "flowing" over its wings... I don't care if the wheels are spinning as fast as they need to go in order to usually gain lift off... no air from forward momentum over wings means plane no fliy
God I can't believe I'm getting into this arguement again. The wind from the prop flowing over the wings does not create lift. The prop creates AIR THRUST, which has nothing to do with what the plane is sitting on. The AIR THRUST causes movement of the plane, and the movement creates the lift via wind on the wings.
The plan could be on the road, a tread mill, a lake, a river, or ice. It doesn't matter. The points of contact that the plane has with the ground are irrelevant. It moves by AIR THRUST, not by any contact with a stationary surface like a car.
The plan could be on the road, a tread mill, a lake, a river, or ice. It doesn't matter. The points of contact that the plane has with the ground are irrelevant. It moves by AIR THRUST, not by any contact with a stationary surface like a car.
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Free spinning wheels or not, the speed at which the wheels are turning has no relation to the plane taking off. The engine is pushing the plane forward it does not provide lift. The flow of air over/under the wing provides lift. On a tread mill there is no air moving over the wings.
Here is another way of putting it. Driving your car down the road at 70 mph stick you hand out the window. The air will force you hand back. Stick you hand out of the window of the cockpit of the plane on a treadmill will there be airflow pushing your hand back?