Airplane and Conveyor Belt Debate

[Homer Simpson]

There was some thread on this I saw a couple weeks back. Basically, it the wheels will turn however fast they want. As soon as the jets fire up the plane will move relative to the stationary ground. Any treadmill beneath it will just make the wheels spin faster. This would only be a problem if the wheels were motorized to make the plane move, but that's not the case.

On the other hand, If the treadmill was running at the same speed in the same direction as the jet as it fires up, the jet would take off with no movement of the wheels.

You don't need math or physics for this type of stuff, just think about it.

 

[Danger]

I seriously think that if this question shows up one more time, I'll scream.

 

[raid517]

Well this is true and this is what I thought. But I thought that this was a good place to shoot it in the head for once and for all.

Everything I know of says that it's a stupid question and of course the aeroplane wouldn't take off - but when you have 50 different guys challenging your assumptions, you can begin to doubt yourself.

GJ

 

[Danger]

Take a look at the other threads on the same subject, which mercifully have been locked. The plane will take off.

 

[fargoth]

oh yeah, i forgot about the fact that the wheels arent motorized, if the jets are what causing the movement the airplane would move... though i think that if the wheels spin too fast there would be lots of heat generation and the plane would move slower. (but if the wheels are ideal, it just means they would move twice as fast)

 

[raid517]

Point me to these other threads please?

GJ

 

[Danger]

Look at 'Classical Physics' in the post entitled 'Airplane question: revisited'. There's a link in the OP to another.

 

[deadmoon]

plane

hi
if you had a plane on a treadmill would it take off?
the treadmill is moving in the oppsite way of the plane at the same speed

thanks

 

[Danger]

Welcome, deadmoon. Unfortunately, you introduced yourself with a question that has absolutely been done to death here. If you check back a few pages, you'll see a very thorough examination of the subject. Bottom line: yes.

 

[brewnog]

KILL IT! LOCK IT! QUICK! KILL IT! KILL IT TIL IT DIES FROM IT!

Argh!

 

[russ_watters]

The answer is yes, unless the question is so poorly worded as to be meaningless. See this thread: https://www.physicsforums.com/showthread.php?t=101259&highlight=treadmill

 

[Doc Al]

And this: https://www.physicsforums.com/showthread.php?t=108477

 

[R1ch]

Plane on a moving runway

Hi all I've just signed up to the forum.
This question seems to have got over the net a bit so sorry if its a re-post

A plane is sat on a runway with some sort of conveyer belt, when the plane moves the conveyer moves in the opposite direction matching the planes speed exactly. Can the plane take off?

 

[russ_watters]

Sorry, we've discussed this ad nauseum and won't go over it again. Do a search of the forum for the topic.

In short, though, the problem is so poorly worded as to not have a definite answer. Regardless, an airplane takes off when the airflow over the wings is fast enough to create enough lift to make the plane fly. That's it. It doesn't matter what the wheels are doing at the time (the plane can even be completely stationary if it has a strong enough headwind).

 

[Kaldarin]

Will the plane fly off ...?

If an airplane is placed on top of a conveyer belt which turns in the oposite direction of the plane with the exact speed as the plane, will it ever take off?

 

[Pengwuino]

This has been discussed over and over and over and over and over and over and the answer is basically yes with the qualification that the question is worded too poorly to be worth anything. Please search the general physics area.

 

[ZapperZ]

I'm almost going to insist a 1-year moratorium on this question.

https://www.physicsforums.com/showthread.php?t=101259

Zz.

 

[kmarinas86]

Conveyor and Plane

Sorry, this question is too fun too resist.

A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in opposite direction).

The question is:

Will the plane take off or not? Will it be able to run up and take off?

Well, to understand how the system works, let's change the settings first:

Instead going 100% of the speed in the opposite direction, have the conveyor belt go 700 knots in the opposite direction. The implications of this are obvious now since the air would be flowing backwards on the wings not forward, therefore the plane will be affected by this movement.

Another thought experiment. Put a Honda civic on a steel treadmill. If it has a spoiler, is the spoiler being used? It isn't. The only wind being generated is from the exhaust and the contact of the air with the moving surfaces of the vehichle and the steel treadmill. The body as a whole is not generating a lift or downforce as if it were traveling fast on the road.

 

[Gokul43201]

This exact question has been discussed in an earlier thread in Physics.

Read the discussion there :

https://www.physicsforums.com/showthread.php?t=101259

 

[russ_watters]

...and will not be discussed again.

The question isn't fun, it's dumb. The only reason there is any doubt as to the answer is because the question is poorly worded and unrealistic (how can the conveyor exert a force on the plane?).

 

[MrsScruffles]

Throwing Myself At Your Scientific Mercy

I'll hope you'll all excuse the intrusion, but I've fled here from another forum in the hope that you will be able to settle a debate that has been raging for far too long. The original question that has causes such furore is this:

A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in opposite direction).

The question is:

Will the plane take off or not?

I did try searching your forums, and saw a similar question with a car, but not a plane. I'm sat in the "no" branch, because I believe that there are no aerodynamic forces at work because essentially the airplane is stationary, and only the wheels are in motion, so you wouldn't get lift. However, the oppposing argument seems to be that the force from the jet engines would cause lift off regardless. I don't think any of us have a good enough grasp of physics to ever formally end this debate. Our formally peaceful forum has turned into something out of Gullivers travels, but instead of everyone divided on which way to eat a boiled egg we're going crazy over a hypothetical plane.

Twenty two pages later and the argument is still going.

So can someone kill this question dead for me?

 

[Pengwuino]

What forum is this?! We've received this question like 20 times!

 

[Mk]

Yeah. What Forum Is It! Do We Have To Wipe Their A** For Them?? I think we need to do a DNS attack on them. And SPAM, yes Spam...

 

[MrsScruffles]

Sorry, as I said, I did do a search and couldn't see it. The question I found was about cars. And as far as I know, I think it's quite viral, and been spread from place to place. Sorry for wasting your time.

 

[fasterthanjoao]

the plane isn't actually moving wrt anything other than the belt so there's no lift from air? surely.. hmm..

 

[FredGarvin]

Board searches are pretty fickle. If you do a search on "conveyor" you will get this thread (which links back to some of the original threads)

https://www.physicsforums.com/showthread.php?t=112124&highlight=conveyor

Please, someone go out into the ether and beg that this topic die a horrible death that it so rightly deserves and smote the boards that started it...amen.

BTW...what board is it that has had this raging debate going on for so long?

 

[ZapperZ]

This question is fast becoming the Most Annoying Question (MAQ).

Zz.

 

[P.G]

Debate

Hey people. I have a problem that I don't know the answer to, but you guys could probably help. Its quite a hot topic on other forums. Anyways, here it is.

A plane is standing on a runway that can move (some sort of conveyer belt). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction).

Can the plane take off?

I say no personally but I've been told it can help!

 

[chroot]

This same question has been answered many, many times already, largely by people like you, P.G, who have come here from another forum. This question is no longer welcome here. Use the search function to find previous discussion on it.

- Warren

 

[userjayson]

plane landing on giant conveyor belt

What would happen if a plane was approaching a runway at 200 mph and the runway (conveyor belt) was moving at 200 mph in the opposite direction. I think if your wheels could take the sudden jolt, they would start turning at 400 mph. Since the plane is being thrusted buy a jet not attached to the wheels, it would continue to go its original 200 mph until the jet was shut off. Once that happens, at what rate do you slow the conveyor belt down so the that the plane is not forced of the back end of the belt. I can't get my mind around this one.. I heard a radio talk show host talking about this one day and was wondering if were possible.