Mythbusters, Plane on a treadmill..

[Say Again Over]

Thedude, you are quite correct, unfortunately you will not stop airflow with a treadmill, jeez!

 

[SplitBar]

Think of a seaplane taking off into a strong current moving in the opposite direction. It will still lift off.

Not necessarily. Assume the water current was flowing at 100MPH. If the sea plane was taking off against the current it would have to attain a "waterspeed" of 101 mph just in order to get air flowing over the wings. The drag from the floats and the lack of power from the engine would never get the sea plane moving that fast thru the water. Add full power to the sea plane into a 100mph water current and the sea plane is going to do nothing but move backwards and never achieve any headwind airflow over the wings.

 

[COOPERVANE]

Not necessarily. Assume the water current was flowing at 100MPH. If the sea plane was taking off against the current it would have to attain a "waterspeed" of 101 mph just in order to get air flowing over the wings. The drag from the floats and the lack of power from the engine would never get the sea plane moving that fast thru the water. Add full power to the sea plane into a 100mph water current and the sea plane is going to do nothing but move backwards and never achieve any headwind airflow over the wings.

That is VERY accurate, the drag on a seaplane would never let it make any headway against a 100kt current, but the drag generated by the tiny tires of a conventional airplane would be 1,000 times less.

Try the roller skate on a treadmill analogy again.

 

[COOPERVANE]

Jeez....no airflow = no fly

I agree, but there WILL be airflow. Don't be so quick to judge without thinking it through. It is a little bit of a trick question. The question states that the treadmill will compensate for any forward speed of the aircraft. The trick is that it CANNOT do it.


The airplane WILL accelerate on the tradmill, thats the point. The tradmill CANT HOLD IT STATIONARY!!! It will try but it CANNOT DO IT

A little later when the light bulb illuminates, there will be some people who will then blame the wording of the original question for their lack of understanding.

 

[ackattacker]

I guess a lot of pilots failed high-school physics.

Reminds me of the time I was flying with another pilot (ATP even, multiple type ratings) and I suggested we alter course to avoid the thunderstorm at our 12 O'Clock and 30 miles. He said no need... the wind was blowing from our right and the storm would be blown away by the time we got there. I tried to explain about heading vs. course and same air mass and all that and ended up just giving up. Not worth arguing I guess.

 

[BGSkyGuy]

when does it air. I want to put some money on this sh!t

 

[ImbracableCrunk]

People are bickering over two different questions. <Sigh>.

If you think the question is "Could a plane on a treadmill accelerate?" then you might get a different answer than "If a treadmill held a plane stationary, would if fly?"

Remember this is a physics question, so theoretical frictionless bearings, etc. would usually apply in a PHY100 class. And therefore, you could create a treadmill that could hold a plane stationary.

Figure out what the givens are and try to answer the same question!

 

[blzr]

I would like to see a segment on wheel rotation prior to touchdown. How much rubber would it actually save????

 

[Rekks Inbound]

People are bickering over two different questions. <Sigh>.

If you think the question is "Could a plane on a treadmill accelerate?" then you might get a different answer than "If a treadmill held a plane stationary, would if fly?"

Remember this is a physics question, so theoretical frictionless bearings, etc. would usually apply in a PHY100 class. And therefore, you could create a treadmill that could hold a plane stationary.

Figure out what the givens are and try to answer the same question!

If the bearings were frictionless, then it would not matter how fast you ran the treadmill. The aircraft would remain stationary. But as soon as you applied a thrust vector to the aircraft it would move of it's own accord regardless of treadmill speed.

Peace.

Rekks

 

[ImbracableCrunk]

If the bearings were frictionless, then it would not matter how fast you ran the treadmill. The aircraft would remain stationary. But as soon as you applied a thrust vector to the aircraft it would move of it's own accord regardless of treadmill speed.

Peace.

Rekks

Okay, so you're choosing the "plane can accelerate ?" version, not the plane stays in one place version of the question.

Remember, some people word the question as, "So you build a treadmill that keeps a plane in one place. . . "

Pax.