A jet plane on a large treadmill

**MTT** · 04-13-2012, 12:13 AM

NMA TEST Questions
I suspect many have answered correctly but reading some of the responses’ is kinda funny.

Air Planes are all about AIR. The engines provide thrust (Movement of Air) to propel the Aircraft Forward. Air Planes fly due to LIFT, which is Air passing over and under the wings.

The only way to overcome the Thrust from moving a plane forward is to create enough resistance on the ground to prevent the plane from moving forward.

when they do engine tests they Set the Wheel Brakes AND Block the wheels with Chalks. (They anchor the plan to the ground to keep it stationary) A treadmill would not perform this task

So the situation described in the question is a fantasy question?

However if you keep a plane stationary in relation to the ground it does not fly as there is NO LIFT being created by Air passing over and under the wings. (UNLESS There is a HEADWIND) of sufficient speed to create lift.

**stuckathuntermtn** · 04-13-2012, 12:22 AM

I was just thinking about this today, for some reason.

**Mustonen** · 04-13-2012, 05:15 AM

Originally Posted by MTT

The only way to overcome the Thrust from moving a plane forward is to create enough resistance on the ground to prevent the plane from moving forward.

Yeah, but who's trying to prevent the plane from moving forward?

Originally Posted by MTT

So the situation described in the question is a fantasy question?

No, the situation described in the question is not a fantasy question. The situation you describe, however - that one's a fantasy. Why do you take a relatively simple premise and rewrite it so it doesn't make any sense? Why do we rewrite the question so that the very premise is impossible? Does that really make any goddamned sense? Why so many insist on doing this fucking escapes me.

Why is the concept of two things moving in opposite directions at identical speeds such a fucking mindbender?

**Jethro** · 04-13-2012, 07:38 AM

Originally Posted by Beaver

Are you "no takeoff" guys fucking stupid or what? Twice for those who don't get it.

The jet plane will take off because it is irrelavant how fast it is going in relation to the ground as it is not driven by wheels but by jets (hence the name of the craft). It's wheels will be spinning like a motherfucker but it will have it's normal airspeed and thus take to the air like, well, a jet. It better have some good wheel berings and some well ballanced wheels.

If the plane does not use it's jets it will not move therefore the treadmill will never need to turn. If it uses it's jets it will begin to move forward, as it moves forward the treadmill will begin to move backwards twice as fast as the jet is moving forward. The jet will continue to accelerate gaining airspeed while the tradmill continues to accelerate twice as fast as the jet. Eventually (slightly longer than normal due to added rolling resistance) the jet will take off. It really does not matter how fast the ground appears to be passing by because like I stated, ground speed is irrelevant. The jets push air not ground so who fucking cares if it is on a treadmill.

Finally a winning answer

edit: didn't realize this was seven years old and 25 pages before I responded

**Tippster** · 04-13-2012, 07:58 AM

That winning answer was on page one.

**Jethro** · 04-13-2012, 08:03 AM

Yeah, I know that now. At the time I responded to the first good answer I read and then realized afterwards the OPs question was seven years old and had 25 pages of debate. I never read past page one.

**MTT** · 04-13-2012, 08:17 AM

Originally Posted by Mustonen

Yeah, but who's trying to prevent the plane from moving forward? ?

Whom ever thought up the silly Idea of a treadmill? A treadmill inder the plane could never prevent it from moving forward.
I think your simple minded

Originally Posted by Mustonen

No, the situation described in the question is not a fantasy question. The situation you describe, however - that one's a fantasy. Why do you take a relatively simple premise and rewrite it so it doesn't make any sense? Why do we rewrite the question so that the very premise is impossible? Does that really make any goddamned sense? Why so many insist on doing this fucking escapes me.

Why is the concept of two things moving in opposite directions at identical speeds such a fucking mindbender?

Really, how would a treadmill ever prevent an Airplane from moving forward? The Engines drive air back from the plane. A treadmill would only prevent forward momentum if the Aircraft propeled itself forward using the Wheels, Like a car. It does not work that way.

**DJSapp** · 04-13-2012, 09:31 AM

This needs to be on every page.

**Mustonen** · 04-13-2012, 09:34 AM

Originally Posted by MTT

Whom ever thought up the silly Idea of a treadmill? A treadmill inder the plane could never prevent it from moving forward.
I think your simple minded

Really, how would a treadmill ever prevent an Airplane from moving forward? The Engines drive air back from the plane. A treadmill would only prevent forward momentum if the Aircraft propeled itself forward using the Wheels, Like a car. It does not work that way.

Yes, yes, reading comprehension is where you failed - I was trying to establish that in my last post, and you continue to demonstrate it. Admirably.

Answer to my first question - "who's trying to prevent the plane from moving forward?": NOBODY is trying to prevent the airplane from moving forwards. The treadmill isn't even trying to do that. The original question never said or even implied that was a goal of the treadmill, you added that yourself. The airplane moves forwards roughly normally and takes off, and the treadmill doesn't even give a shit, it just ends up spinning backwards, starting at 0mph on up to takeoff speed.

Answer to my other questions: I don't really have any idea why some people (apparently inclusive of you) can be so fucking dense.

**Mustonen** · 04-13-2012, 09:37 AM

Originally Posted by Jethro

Finally a winning answer

edit: didn't realize this was seven years old and 25 pages before I responded

Beaver's so close, but he's misplacing the *2 multiple - the wheels spin at twice the speed, not the treadmill. (treadmill speed)*-1 = (airplane speed). (Wheel spin) = (airplane speed) + (treadmill speed)*-1

Originally Posted by DJSapp

This needs to be on every page.

That's cute, but it's not the answer to the question posed by the thread. That's like answering "what is 2+2" with "4, because the square root of 4 is 2." The motorcycle, if it was on the treadmill, would drive forwards, it doesn't matter where force is applied. edit: I know you know that, at least you did 7 years ago.

**Brock Landers** · 04-13-2012, 09:37 AM

I still dont get it. Can anyone explain? It doesnt take off, right?

**stuckathuntermtn** · 04-13-2012, 10:17 AM

No. There is no airflow over the lifting surface.
0 Knots True Airspeed.
It's Ground Speed could be 400KTA relative to the tread mill, but as long as there is 0KTA over the airfoil, it can't take off.
That's why planes take-off and land into the wind. While the plane may be fighting a head wind and have a lower ground speed, its airspeed is higher by however many knots the headwind is.
for example: at 200kts ground speed in a 10kt headwind, the kta is 210kts. and off into the wild blue yonder you go.

Morans.
http://en.wikipedia.org/wiki/Airfoil

**Jethro** · 04-13-2012, 10:29 AM

Originally Posted by stuckathuntermtn

No. There is no airflow over the lifting surface.
0 Knots True Airspeed.
It's Ground Speed could be 400KTA relative to the tread mill, but as long as there is 0KTA over the airfoil, it can't take off.
That's why planes take-off and land into the wind. While the plane may be fighting a head wind and have a lower ground speed, its airspeed is higher by however many knots the headwind is.
for example: at 200kts ground speed in a 10kt headwind, the kta is 210kts. and off into the wild blue yonder you go.

Morans.
http://en.wikipedia.org/wiki/Airfoil

No, see motorcycle/rollerblader picture above. If the airplane used its wheels a a drive mechanism this would be true, but it uses its jet engines.

**Captain Anal** · 04-13-2012, 10:38 AM

The plane takes off, you dummies. DJSapp has it right. The treadmill could be going 6 billion mph, but the jets would still push the plane forward in relation to the ground the treadmill is sitting on... but more importantly, it would push the plane forward in relation to the air surrounding the treadmill. So.. that creates LIFT. Who cares about the wheels? The jet engines don't give a shit about the treadmill. They don't push against the ground, they push against the AIR.

**MagnificentUnicorn** · 04-13-2012, 10:39 AM

Originally Posted by Mustonen

Yes, yes, reading comprehension is where you failed - I was trying to establish that in my last post, and you continue to demonstrate it. Admirably.

Answer to my first question - "who's trying to prevent the plane from moving forward?": NOBODY is trying to prevent the airplane from moving forwards. The treadmill isn't even trying to do that. The original question never said or even implied that was a goal of the treadmill, you added that yourself. The airplane moves forwards roughly normally and takes off, and the treadmill doesn't even give a shit, it just ends up spinning backwards, starting at 0mph on up to takeoff speed.

Answer to my other questions: I don't really have any idea why some people (apparently inclusive of you) can be so fucking dense.

You guys are funny, you're both arguing that the pane will take flight.

**DJSapp** · 04-13-2012, 10:45 AM

Originally Posted by Jethro

If the airplane used its wheels a a drive mechanism this would be true, but it uses its jet engines.

I take everything back and completely disagree with everything I have ever posted in this thread. Airplanes do use their wheels as a drive mechanism, and every plane that is in the air is actually on an invisible road made out of ice. Clearly, without the wheels touching something, the plane could not possibly ever move It's all a gov't conspiracy because Jesus never meant humans to fly.

**Jethro** · 04-13-2012, 10:49 AM

delete post

**Jethro** · 04-13-2012, 10:52 AM

Originally Posted by DJSapp

I take everything back and completely disagree with everything I have ever posted in this thread. Airplanes do use their wheels as a drive mechanism, and every plane that is in the air is actually on an invisible road made out of ice. Clearly, without the wheels touching something, the plane could not possibly ever move It's all a gov't conspiracy because Jesus never meant humans to fly.

Thanks, I did not know that. We should paint those roads so we can see them and drive on them

**Garbanzo** · 04-13-2012, 10:57 AM

It would depend on the size of the treadmill. If it was miles long and wide enough, then it would affect the air above it and result in a big headwind. The jet might lift off without moving forward but only for a second before encountering normal air and falling. At which point it would fly up as it encounters the fast airstream ... and then fall again.

**Mustonen** · 04-13-2012, 10:59 AM

Originally Posted by AaronWright

You guys are funny, you're both arguing that the pane will take flight.

Right? Getting the right answer doesn't mean you're right, though. A broken clock is right twice a day. This is why your math teacher in high school wanted you to show your work.

Whether or not the plane moves forwards has little to do with where the force is being applied. Even if the plane moved forwards because of motors driving the wheels, it could take off of the treadmill (though it wouldn't fly far).

**f2f** · 04-13-2012, 11:02 AM

what's really going to bake your noodle:

also, this:

and, of course:

**montanaskier** · 04-13-2012, 11:05 AM

what if the treadmill was on wheels?

**From_the_NEK** · 04-13-2012, 11:11 AM

Originally Posted by montanaskier

what if the treadmill was on wheels?

I think it would also have to be nuclear powered to be effective.

**flyandski365** · 04-13-2012, 11:28 AM

Originally Posted by Mustonen

Whether or not the plane moves forwards has little to do with where the force is being applied. Even if the plane moved forwards because of motors driving the wheels, it could take off of the treadmill (though it wouldn't fly far).

That last part sounds pretty wrong to me. If the treadmill matches the speed of the rotating wheel in the opposite direction, how does it move forward? I, mean that's how a treadmill works right?