WILL IT FLY?

Heike said:
So what you're saying is that if this were a perfect system where the treadmill countered the plane's velocity with its own negative velocity at all times it would not fly, but since the MythBursters won't be able to design a perfect system it will fly?
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Even in a perfect system it should still fly. There's only so much friction that can thereotically exist between the wheels of a plane and the surface of a treadmill. If the plane's going fast enough, no matter how fast the treadmill is going, that force will be overcome and it will move forward.

BUT, I'm willing to be proven wrong so I'm looking forward to the MythBusters show lol.
 
Kalia said:
Even in a perfect system it should still fly. There's only so much friction that can thereotically exist between the wheels of a plane and the surface of a treadmill. If the plane's going fast enough, no matter how fast the treadmill is going, that force will be overcome and it will move forward.

BUT, I'm willing to be proven wrong so I'm looking forward to the MythBusters show lol.
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You're right, the rolling friction would be the only component of force from the treadmill to the aircraft, regardless of speed, and since the thrust isn't going through the wheels (which is what I couldn't separate in my mind from a car) it will overcome the rolling friction.
 
The way I see it, math / physics / friction / what have you doesn't even need to be discussed at this point. Think of it in terms of television production value. Would they even air the segment if the viewers won't get to see something cool? Seems to me like it will take off.
 
Wowowow. Was just coming here to post it was on tonight, heh.

Was interesting to see a post of mine on the top! Hurray!

Enjoy~
 
The model test was better than the full scale test, but the results were pretty conclusive in both tests.

It was a fun debate though. I always really enjoy a good thought exercise that isn't simply a riddle.
 
Well, can someone post some details of what happened... Won't be able to see this in Tokyo unless it gets put on YouTube... :(

I'd really like to actually see it after all of this debate. lol.
 
Eticket said:
good thing I didn't come in here til now. gg on the pst spoilers.

pretty flawed test overall but it's the best you can do with it I suppose
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You knew someone was going to ask who can't see the show. You know someone's going to answer. /shrug. I posted this at about the same time it was airing in PST, so you were smart then.


Aangeliceus said:
Well, can someone post some details of what happened... Won't be able to see this in Tokyo unless it gets put on YouTube... :(
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http://www.youtube.com/watch?v=IbRcg3ji_Pc

There's some footage there. They had a smaller scale version of RC plane on a treadmill. Not as cool. The full scale they basically made a conveyor belt out of a huge thing of tarp, and had a truck drag it backwards at the same speed as plane went forwards.

Now what I question, is a plane's speedometer. If it's not based on the rotation of the wheels, what is it based on? I would think essentially to go same "speed" it'd be going double what the truck is because wheels free spinning.

Anyone know how the mechanics on a plane work in that respect?
 
The airplanes have a little tube (Pitot Tube) on the wing usually, it measures airspeed by the speed of the air coming into the tube.

The airspeed system is tied to the same system as the atlimeter, which is kind of complex if you have never seen it before. The system itself is simplex in operation.

Read Here: http://en.wikipedia.org/wiki/Pitot_tube

Unless something has changed, which I doubt, planes dont have "Speedometers" attached to the wheels.

Zeri said:
Now what I question, is a plane's speedometer. If it's not based on the rotation of the wheels, what is it based on? I would think essentially to go same "speed" it'd be going double what the truck is because wheels free spinning.

Anyone know how the mechanics on a plane work in that respect?
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BTW.. Thanks for the link Zeri.
 
Ah okay. Makes perfect sense! They measured the speed needed to take off, which I think was 25mph (It was a really light plane). I was thinking, if they said to Jamie, "Okay you drive 25mph while he takes off at that speed," if it were based on wheel rotation, and they free spin, his plane would in fact be capped at half the true "speed" with respect to the air, that it needed to take off.

I wonder if wind throws off the tube at all, or if it's narrow enough that wind speed and direction really is negligible? They did it in the morning when there was no wind, but just in general curious.

Thanks Aang! ^.^
 
Zeri said:
Now what I question, is a plane's speedometer. If it's not based on the rotation of the wheels, what is it based on?
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This is the part I think most people get tripped up on when they say it won't fly. The wheels have absolutely nothing to do with the speed of the plane. People try to compare it to a car. In a car, it's the wheels that push the car forward. The actual force to move the car comes from the wheels. In a plane, the wheels are being moved by the thing creating the force, which is the thrust from the engines. So all that happens when the conveyor belt is moving the opposite direction is that the wheels are spinning twice as fast.
 
Kalia said:
This is the part I think most people get tripped up on when they say it won't fly. The wheels have absolutely nothing to do with the speed of the plane. People try to compare it to a car. In a car, it's the wheels that push the car forward. The actual force to move the car comes from the wheels. In a plane, the wheels are being moved by the thing creating the force, which is the thrust from the engines. So all that happens when the conveyor belt is moving the opposite direction is that the wheels are spinning twice as fast.
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Well I'm aware that the wheels exert no force. But before Aang posted about the tube, I had no idea how a plane measured its own speed. I figured air speeds were calculated estimates, and on the ground it had something hooked up to the wheels since well, in most cases, a plane isn't sitting on a conveyor belt. So otherwise, monitoring how fast the jet thrust is making the wheels spin wouldn't be too shabby at measuring speed.


Conclusion: The Pilot Tube solves all!
 
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