Will the airplane fly?

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Originally posted by AThousandYoung
Let's look at this from another angle. Suppose an airplane was on a normal, stationary runway and had a tailwind blowing at 100 knots. Could the plane take off if it could go only 100 knots relative to the ground and could not change it's direction?

when a pilot flys they always take off and land into the wind.
so if a pilot did have the wind at their tail then they schouldent even be aloud to fly. there a hazard in the air.

Originally posted by drumset04
when a pilot flys they always take off and land into the wind.
so if a pilot did have the wind at their tail then they schouldent even be aloud to fly. there a hazard in the air.

I doubt planes would be allowed to take off from treadmills either. That's not the point. This is a physics question, not an airport regulations one.

Ok, this has got to be the dumbest question ever. If the plane is in fact on a "treadmill" the planes speed relative to the ground will be zero. So if the plane took off at a speed of zero it would be hovering. I have never seen a plane hovering (except of course the Osprey, when not crashing). You guys are hearing hoofs and looking for zebras.

This is not a physics question, it is a question of common sense which apparently is not so common. And this guy wants to fly..scarry

Cheers!

Originally posted by likeforest
Ok, this has got to be the dumbest question ever. If the plane is in fact on a "treadmill" the planes speed relative to the ground will be zero. So if the plane took off at a speed of zero it would be hovering. I have never seen a plane hovering (except of course the Osprey, when not crashing). You guys are hearing hoofs and looking for zebras.

T ...[text shortened]... f common sense which apparently is not so common. And this guy wants to fly..scarry

Cheers!

Nice try idiot.

http://www.straightdope.com/columns/060203.html
http://www.straightdope.com/columns/060303.html

A nice simple answer. Yes it can take off unless the treadmill is constantly accelerating. And a good analogy about rollerskates on a treadmill.

This is absolutley horse s**t. I refuse to believe some random guy on the web. Please show me footage of a 747 hovering in mid-air with zero foward velocity. What exactly happens to the plane after it "takes off"?

Message-board discussions of this question tend to feature a lot of posters who haven't yet arrived at BR #1 talking right past those who have, insisting more and more loudly that the plane won't take off. Then there's a whole other breed of disputants who, whether or not they've cracked the riddle as originally posed, prefer to reframe it by proposing progressively more esoteric assumptions, refinements, analogies, etc. Often they arrive at a separate question entirely: Is there a way to set up the conveyor so that it overcomes the thrust of the engines and the plane remains stationary and doesn't take off?

This is taken from straight dope. In the original question i assumed the conveyor would overcome thrust keeping the plane stationary. Apparently this is not the case. As long as you are saying the plane is moving foward relative to the ground, then yes I will agree, the plane will take off.

A plane will fly if the difference in air pressure between the two wing surfaces is great enought to create the lift required to offset the weight of the plane. There are two ways to generate that pressure - the plane moving forward in air or, the air moving over the wing artificially (wind machine etc) It is possible for a plane , stationary relative to the earths surface to fly (hover) if the air flow is sufficient and sustained. Birds do it all the time in strong winds.

If the treadmill is capable of generating that air flow then the plane will fly - if it cannot then it will not.

skeeter

Originally posted by skeeter
A plane will fly if the difference in air pressure between the two wing surfaces is great enought to create the lift required to offset the weight of the plane. There are two ways to generate that pressure - the plane moving forward in air or, the air moving over the wing artificially (wind machine etc) It is possible for a plane , stationary relative to th ...[text shortened]... of generating that air flow then the plane will fly - if it cannot then it will not.

skeeter

This question was put on an aviation forum, and most of the pilots said that the plane WILL take off, (and I agree). It was also put on a physics forum, and its over 300 pages long now, its about half and half.


The question clearly states that the plane IS moving forward, (Its not stationary like everyone thinks it is) The treadmill is going backwards, Note that ground speed has nothing to do with whether the plane can take off since the plane is propelled in the air.

So the plane WILL take off.

The pressure thing you talk about is nelgible, because IF the treadmill did create a wind tunnel, the area of low pressure would down, therefore pulling the aircraft down.

Originally posted by sonhouse
Where are you going back east? Maybe your family and mine can have a get together, scratch out some tunes. We live north of Philly, I guess you know that. We just did a couple of local gigs, first my wife has been able to do, tough being a singer when you are stricken with asthma. We did one of the gigs with just me and Kevin, my son, we did just instrumentals, guitars and mandolin. It was fun but would have been better with Susan.

Im not quite sure where were all going, I think were hitting around 20 states, in a 2 month period, but not quite getting that far north, usually OH is the farthest north we go unless someone books us some gigs. I'll know more in a month and let you know.

Where do you normally play? like music festivals and such? one of our biggest audience was in Pennsylvania, about 2000 people at one festival. Alot of people there in Pennsylvania.

Originally posted by flyUnity
This question was put on an aviation forum, and most of the pilots said that the plane WILL take off, (and I agree). It was also put on a physics forum, and its over 300 pages long now, its about half and half.


The question clearly states that the plane IS moving forward, (Its not stationary like everyone thinks it is) The treadmill is going backwards, ...[text shortened]... create a wind tunnel, the area of low pressure would down, therefore pulling the aircraft down.

The 'pressure thing' that I refer to is the only 'thing' that enables a plane to fly. That pressure is created by the differing rates of flow over the two surfaces. Air flow over the longer surface, the top, is faster so less pressure whilst the flow over the shorter is relatively slower therefore more pressure and that is what produces the lift. Nothing else does.

skeeter

Originally posted by XanthosNZ
Nice try idiot.

http://www.straightdope.com/columns/060203.html
http://www.straightdope.com/columns/060303.html

A nice simple answer. Yes it can take off unless the treadmill is constantly accelerating. And a good analogy about rollerskates on a treadmill.

Interesting. I guess I was wrong!

Originally posted by flyUnity
A plane is standing on a runway that can move (some sort of treadmill). The plane moves in one direction, while the conveyer moves at the same speed but in the opposite direction. Can the plane take off?"

(copied and pasted from another source)

Bernouli works on air flow over the wings, not ground speed under the tires.

Originally posted by likeforest
This is absolutley horse s**t. I refuse to believe some random guy on the web. Please show me footage of a 747 hovering in mid-air with zero foward velocity. What exactly happens to the plane after it "takes off"?

Why would the plane have to hover in relation to the air?