If A Plane Took Off A Conveyor Belt...

David L · Fri Jan 18, 2008 2:08 pm

Quoting Mark5388916 (Reply 848):
apparently they read the forums

But presumably they will only be examining Option 1, not Option 3. crazy

I think it's worth a reminder that proponents of Option 1 argue that, in "real life", excessive rotational speed of the wheels would be the limiting factor and the belt would not prevent the aircraft from gaining airspeed. Smile

bok269 · Sat Jan 19, 2008 7:00 pm

Quoting StealthZ (Reply 847):
Wrong, the Aircraft does NOT have to be moving relative to the Earth it only has to be moving relative to the air.

Bad phrasing on my part...what I meant to say was that unless you have extremely strong headwinds, or a converyor belt that can move air as well, you will not take off without moving relative to the earth.

kcrwflyer · Mon Jan 21, 2008 1:42 am

This thread is still alive?

How can a plane takeoff if its not moving forward...?

Starlionblue · Mon Jan 21, 2008 3:26 am

Quoting KcrwFlyer (Reply 852):

How can a plane takeoff if its not moving forward...?

It is moving forward. The conveyor belt does not affect the plane's ability to do this.

bok269 · Mon Jan 21, 2008 6:08 am

Quoting Starlionblue (Reply 853):

It is moving forward. The conveyor belt does not affect the plane's ability to do this.

Right, but wouldn't moving forward make having a conveyor belt useless in the first place?

kcrwflyer · Mon Jan 21, 2008 7:02 am

Quoting Starlionblue (Reply 853):
It is moving forward. The conveyor belt does not affect the plane's ability to do this.

Quoting Bok269 (Reply 854):
Right, but wouldn't moving forward make having a conveyor belt useless in the first place?

Are you talking about the conveyor belt actually moving the direction the plane is moving? Thus causing it to accelerate and not remain stationary? If that were the case, then yeah...itd fly.

Starlionblue · Mon Jan 21, 2008 8:22 am

Quoting Bok269 (Reply 854):
Right, but wouldn't moving forward make having a conveyor belt useless in the first place?

The conveyor belt was never "useful". Wink

Quoting KcrwFlyer (Reply 855):
Are you talking about the conveyor belt actually moving the direction the plane is moving? Thus causing it to accelerate and not remain stationary? If that were the case, then yeah...itd fly.

If we assumes brakes are off and the wheels are on the conveyor belt, the conveyor belt will impart little motion to the aircraft. The wheels will effective act as bearings.

David L · Mon Jan 21, 2008 2:09 pm

Quoting KcrwFlyer (Reply 855):
Are you talking about the conveyor belt actually moving the direction the plane is moving?

We're talking about all of these, and more...

Quoting David L (Reply 523):
1. Belt opposes aircraft's ground-speed, not its "belt-speed" ("classic" scenario)
2. Belt stops tyres rotating ("as stated" version 1),
3. Magic force stops the aircraft from gaining air/groundspeed ("as stated" version 2)
4. The question was never asked in the first place and what are you talking about?

Results:

1. Aircraft takes off at normal air/groundspeed but wheels rotate twice as fast as normal,
2. Aircraft takes off at normal air/groundspeed but wheels not rotating,
3. Twighlight zone with magic force - belt changes colour, slips in and out of focus, we all feel one with the universe. "But what happens to the plane?"... "I don't care, look at all the colours!"...
4. With hindsight, I'd like to believe this was the case.

iwok · Wed Jan 23, 2008 9:13 pm

Quoting Sovietjet (Reply 841):
I'd like to know how mythbusters will be able to INSTANTANEOUSLY match the wheel speed with the belt....in order for them to prove this wrong the experiment parameters have to be the same...and they most surely wont be.

Perhaps they record what the instantaneous velocity is supposed to be, and then try to spool up the belt but overshoot the speed a little so that the average is maintained.

iwok

kbfispotter · Thu Jan 24, 2008 9:30 am

I just saw a preview for next weeks episode of Mythbusters, and they are tackling this!!!!!! It looked like they had a cub or something set up to try this out... Should be interesting to watch.

Kris

pwm2txlhopper · Sun Jan 27, 2008 2:52 am

I see this thread and wish it would just die! After years on here, It's by far the most stupid and ridiculous thread I've ever seen. However, I guess other's enjoy it so I thought I'd let you all know I just saw a commercial for an upcoming episode of Myth Busters and the exact topic of this thread is going to be the focus of the show. I can't believe it! There's no airspeed gained on a conveyor belt! No air moving over the wings America, therefore it can't fly! it's that simple Arggg... What's there to solve?!? Didn't catch the date the episode was going to air. I was busy on the computer, but heard the commercial and almost fell out of my chair!

Boston92 · Sun Jan 27, 2008 4:58 am

The episode is on Wednesday, and the plane takes off.

kbfispotter · Sun Jan 27, 2008 8:03 am

I am begining to wonder if the Mythbusters used a conveyor belt as a catapult to launch the aircraft into the air... Think about it, that one would work....

Kris

David L · Sun Jan 27, 2008 11:16 am

Quoting PWM2TXLHopper (Reply 860):
I see this thread and wish it would just die! After years on here, It's by far the most stupid and ridiculous thread I've ever seen

And I could say the same about hundreds of other threads that seem far more stupid to me. I think after 860 posts, we all need to accept that it's quite a popular thread. Smile

Quoting PWM2TXLHopper (Reply 860):
There's no airspeed gained on a conveyor belt! No air moving over the wings America, therefore it can't fly! it's that simple Arggg... What's there to solve?!?

If only you'd actually read the thread you claim is so stupid. biggrin

Starlionblue · Sun Jan 27, 2008 12:25 pm

Quoting KBFIspotter (Reply 862):
I am begining to wonder if the Mythbusters used a conveyor belt as a catapult to launch the aircraft into the air... Think about it, that one would work....

If you set the brakes, sure. But I doubt that the Mythbusters have the sort of budget that would require.

Quoting PWM2TXLHopper (Reply 860):
There's no airspeed gained on a conveyor belt! No air moving over the wings America, therefore it can't fly! it's that simple Arggg... What's there to solve?!?

I think you're missing the point.

jetblueguy22 · Sun Jan 27, 2008 2:01 pm

Mythbuster busted it so that good enough for me!
Blue
P.S. I didn't think they allowed 865 posts?

iwok · Sun Jan 27, 2008 5:05 pm

Quoting PWM2TXLHopper (Reply 860):
I see this thread and wish it would just die! After years on here, It's by far the most stupid and ridiculous thread I've ever seen.

And yet you still feel the primal need to post here Wink

Quoting PWM2TXLHopper (Reply 860):
There's no airspeed gained on a conveyor belt! No air moving over the wings America, therefore it can't fly! it's that simple Arggg...

Not to open up a can-o-worms, but you might want to check out the theories that have been developed.

Quoting KBFIspotter (Reply 862):
I am begining to wonder if the Mythbusters used a conveyor belt as a catapult to launch the aircraft into the air... Think about it, that one would work....

But the question is: "does it match the wheel speed exactly instantaneously, or is there a lag." Anything short of instantaneaous is not acceptable.

iwok

pwm2txlhopper · Sun Jan 27, 2008 8:56 pm

Quoting Iwok (Reply 866):
And yet you still feel the primal need to post here

I was posting here because I saw the commercial and didn't realize somebody else had posted the same info moments before. And I have read the thread, it's ridiculous! It shows how many people on here have no idea how an airplane produces lift and flies.

[Edited 2008-01-27 13:00:48]

Jetlagged · Sun Jan 27, 2008 11:23 pm

Quoting PWM2TXLHopper (Reply 867):
And I have read the thread, it's ridiculous! It shows how many people on here have no idea how an airplane produces lift and flies.

Everyone who has posted here understands how an aircraft produces lift. What some have misunderstood, including you it seems, is the effect of the conveyor belt on the aircraft, or rather the lack of it.

Starlionblue · Sun Jan 27, 2008 11:26 pm

Quoting PWM2TXLHopper (Reply 867):
And I have read the thread, it's ridiculous! It shows how many people on here have no idea how an airplane produces lift and flies.

Ironically, then you post this:

Quoting PWM2TXLHopper (Reply 860):
No air moving over the wings America, therefore it can't fly! it's that simple

And that's not how the conveyor would work. Wink

Here are the four laws again:

Quoting David L (Reply 523):
I think there are 4 possibilities:

1. Belt opposes aircraft's ground-speed, not its "belt-speed" ("classic" scenario)
2. Belt stops tyres rotating ("as stated" version 1),
3. Magic force stops the aircraft from gaining air/groundspeed ("as stated" version 2)
4. The question was never asked in the first place and what are you talking about?

Results:

1. Aircraft takes off at normal air/groundspeed but wheels rotate twice as fast as normal,
2. Aircraft takes off at normal air/groundspeed but wheels not rotating,
3. Twighlight zone with magic force - belt changes colour, slips in and out of focus, we all feel one with the universe. "But what happens to the plane?"... "I don't care, look at all the colours!"...
4. With hindsight, I'd like to believe this was the case.

David L · Mon Jan 28, 2008 1:03 am

Quoting Iwok (Reply 866):
Anything short of instantaneaous is not acceptable.

Maybe for you Option 3 Merchants. biggrin

Quoting Jetlagged (Reply 868):
What some have misunderstood, including you it seems, is the effect of the conveyor belt on the aircraft, or rather the lack of it.

In Option 1, the limiting factor would be the wheels rotating much faster than they were designed to do, not the minimal force imparted to the aircraft by the conveyor belt.

And that is one of the main reasons the thread is so long. Someone who doesn't read the thread chimes in with the Classic Misunderstanding and the whole argument has to be conducted from start to finish for the umpteenth time. Smile

Quoting Starlionblue (Reply 869):
Here are the four laws again:

Fame at last! Still not as often quoted in this thread as this key point...

Quoting SlamClick (Reply 148):
The wheels don't drive the airplane.
The wheels don't drive the airplane.
The wheels don't drive the airplane.
The wheels don't drive the airplane.
The wheels don't drive the airplane.

BoeingOnFinal · Mon Jan 28, 2008 1:34 pm

Quoting David L (Reply 870):
And that is one of the main reasons the thread is so long. Someone who doesn't read the thread chimes in with the Classic Misunderstanding and the whole argument has to be conducted from start to finish for the umpteenth time.

No, that is not why the thread is so long. It is because those who actually is competent enough to figure out this ridiculously easy question can't fight the urge to try (and I say try) to convince every single one applying silly ideas in this thread that their ideas are wrong. Smile

It is impossible to implant or alter peoples mental model of aerodynamics and physics without teaching them the fundamentals, and there are several books that do just that. And I repeat, books, not short posts. Although 800 of'em might have some impact, I'm afraid most of them creates confusion rather than solutions.

Starlionblue · Mon Jan 28, 2008 2:21 pm

Quoting BoeingOnFinal (Reply 871):

No, that is not why the thread is so long. It is because those who actually is competent enough to figure out this ridiculously easy question can't fight the urge to try (and I say try) to convince every single one applying silly ideas in this thread that their ideas are wrong.

Guilty!

David L · Mon Jan 28, 2008 4:23 pm

Quoting BoeingOnFinal (Reply 871):
No, that is not why the thread is so long.

One of the main reasons, I said. In addition to the reason you gave, there's also the fact that entirely different interpretations were being discussed in the same thread. Smile

Quoting Starlionblue (Reply 872):
Guilty!

Ditto, in the case of Option 1, anyway!

tdscanuck · Mon Jan 28, 2008 10:14 pm

Quoting Jetblueguy22 (Reply 865):
P.S. I didn't think they allowed 865 posts?

Ordinarily, no. But this particular thread is now such an academic curiosity that, for the sake of science and posterity, it must be allowed to continue to its natural end. It's like staring at a car accident...you know you shouldn't, but you just have to look to see exactly how bad it can be.

Tom.

Boston92 · Mon Jan 28, 2008 11:14 pm

I do hope y'all know that even after the Mythbusters prove the airplane flies, there will still be the idiots who don't get it, and say they screwed up and that with a belt, the plane is not moving, and there is no wind going over wings, and that it is a ridiculous thread, and that we are all missing the point that the airplane is not moving, and they use about 7 !!!!!!! after everything they say, when truly, they are the ones who look like udder jackasses (but they just have not figured it out yet).

That felt good.

David L · Tue Jan 29, 2008 3:58 pm

Quoting Boston92 (Reply 875):
I do hope y'all know that even after the Mythbusters prove the airplane flies, there will still be the idiots who don't get it, and say they screwed up and that with a belt

True, for Option 1. Proponents of Option 3 are, of course, entitled to believe that but then Option 3 doesn't need any scientific backing. It pretty much decrees that the aircraft doesn't move and the discussion is more or less about how the belt and wheels need to behave in order to achieve that. crazy

Quoting Boston92 (Reply 875):
That felt good.

I feel your pain. biggrin

Boston92 · Tue Jan 29, 2008 6:59 pm

Quoting David L (Reply 876):
True, for Option 1. Proponents of Option 3 are, of course, entitled to believe that but then Option 3 doesn't need any scientific backing. It pretty much decrees that the aircraft doesn't move and the discussion is more or less about how the belt and wheels need to behave in order to achieve that.

But I believe the original mystery was if the belt matches the speed of the plane and not the speed of the wheels. The one thing that just needs to be proved to these bozo's is that the plane will move as NORMAL when the belt is going ANY speed, LESS the friction between the wheels and belt.

sovietjet · Tue Jan 29, 2008 7:05 pm

Quoting Nighthawk (Reply 5):
yes the aircraft would take off, the conveyor belt will cause the wheels to spin in the opposite direction of movement, but eventually the thrust from the engines will counter the push of the conveyor belt. The wheels will spin at an infinite speed, but this will not push the aircraft back, the force of the engines will move the aircraft forward and it will eventually take off normally. The aircraft will continue to move forward at takeoff speed, but the wheels may well be spinning at 1000+ mph.

I still believe this is the most plausible answer. Takes off with wheels spinning at infinity. Smile

DaBuzzard · Tue Jan 29, 2008 8:29 pm

Quoting Sovietjet (Reply 878):
Takes off with wheels spinning at infinity.

Slight problem with that.

E = mc^2 Little manipulation gives us m=e/c^2

As the wheel rotates faster, it has more energy (e gets larger). As the rotational speed approaches infinity, so does the energy. Infinite speed would give us infinite energy which would give us infinite mass.

Infinite mass would cause the wheel to have an infinite gravity field causing everything within the reach of the field (which would be everything in the universe) to be collapsed into a singularity, and the universe as we know it would instantly cease to exist.

So it won't fly..........because it will no longer exist. stirthepot

tdscanuck · Tue Jan 29, 2008 9:28 pm

Quoting DaBuzzard (Reply 879):
Infinite mass would cause the wheel to have an infinite gravity field causing everything within the reach of the field (which would be everything in the universe) to be collapsed into a singularity, and the universe as we know it would instantly cease to exist.

I think that was covered by outcome 3:

Quoting Starlionblue (Reply 869):
3. Twighlight zone with magic force - belt changes colour, slips in and out of focus, we all feel one with the universe. "But what happens to the plane?"... "I don't care, look at all the colours!"...

Tom.

Starlionblue · Wed Jan 30, 2008 12:06 am

Quoting Boston92 (Reply 877):
The one thing that just needs to be proved to these bozo's is that the plane will move as NORMAL when the belt is going ANY speed, LESS the friction between the wheels and belt.

Well put.

iwok · Wed Jan 30, 2008 4:53 am

Quoting Boston92 (Reply 877):
But I believe the original mystery was if the belt matches the speed of the plane and not the speed of the wheels.

I think the actual OP was a highly complex question, and the poster knew how difficulty the instantaneous issue would add.

Quoting Starlionblue (Reply 869):

1. Belt opposes aircraft's ground-speed, not its "belt-speed" ("classic" scenario)
2. Belt stops tyres rotating ("as stated" version 1),
3. Magic force stops the aircraft from gaining air/groundspeed ("as stated" version 2)
4. The question was never asked in the first place and what are you talking about?

We still need to add: friction between the belt and wheels is overcome and the plane takes off bigthumbsup

Quoting DaBuzzard (Reply 879):
So it won't fly..........because it will no longer exist.

iwok

ShyFlyer · Wed Jan 30, 2008 6:07 am

If a plane took off a conveyor belt...in the forest...and no one was around to see it...does it have to comply with the noise abatement procedure?

mischievous

Starlionblue · Wed Jan 30, 2008 8:29 am

For the record, I'd just like to note that the 4 Laws of Airplane Conveyors (TM) are David L's, not mine. I simply parrot him. Wink

airfoilsguy · Wed Jan 30, 2008 8:59 am

Quoting DaBuzzard (Reply 879):
So it won't fly..........because it will no longer exist.

Have you not read EVERY single post in this thread? That was my theory 4 months ago. Smile

Quoting Airfoilsguy (Reply 796):
Ok, after 795 posts I will let you in on a secret. I know what the answer is.
The plane will not take off nor will the plane not take off. After rotation the plane will immediately implode into itself and form a new black hole wiping out all human existence as we know it.
Thats it, thread over, it can now be locked, and we can all go on with our lives.

David L · Wed Jan 30, 2008 10:25 am

Quoting Boston92 (Reply 877):
But I believe the original mystery was if the belt matches the speed of the plane and not the speed of the wheels.

Yes, that's Option 1, the classic version.

Quoting Sovietjet (Reply 878):
Takes off with wheels spinning at infinity.

I didn't really get involved with Option 3 but I thought the conclusion was that it couldn't move, by definition. In Option 1, it would take off with the wheels spinning at twice the usual rate.

Quoting DaBuzzard (Reply 879):
As the wheel rotates faster, it has more energy (e gets larger). As the rotational speed approaches infinity, so does the energy. Infinite speed would give us infinite energy which would give us infinite mass.

Yes, for Option 3. Since the point of Option 1 was to prove that a real airliner wouldn't have much difficulty overcoming the force of a real belt, we agreed with SlamClick's proposal that the belt could be pre-programmed to accelerate accordingly so there was no need for "infinite speed" or "instantaneous reaction" - it was the "real world" option. Smile

Quoting ShyFlyer (Reply 883):
If a plane took off a conveyor belt...in the forest...and no one was around to see it...does it have to comply with the noise abatement procedure?

Which Option? duck

keta · Wed Jan 30, 2008 12:27 pm

Quoting ShyFlyer (Reply 883):
If a plane took off a conveyor belt...in the forest...and no one was around to see it...does it have to comply with the noise abatement procedure?

Yes, if there's somebody to hear it rather than see it Big grin

DaBuzzard · Wed Jan 30, 2008 4:32 pm

Quoting Airfoilsguy (Reply 885):
Have you not read EVERY single post in this thread?

Dang, thought I had read them all.....musta missed Smile

Mind you, I don't think it even makes it to rotation. I'm thinking the black hole forms the instant the experiment starts.

Wonder if the Mythbusters realize they may end everything just by attempting this? rotfl

Really though, we all know you don't need no steenkin wheels to take off Smile

View Large View Medium
Click here for bigger photo!

airfoilsguy · Wed Jan 30, 2008 9:44 pm

Quoting DaBuzzard (Reply 888):

Really though, we all know you don't need no steenkin wheels to take off

There is an interesting aspect, what if we take wheels out of the equation and replace them with skis on an iced conveyor? duck

David L · Wed Jan 30, 2008 10:04 pm

Quoting Airfoilsguy (Reply 889):
what if we take wheels out of the equation and replace them with skis on an iced conveyor?

~~Simpsons already did it~~ That was covered way back in the thread somewhere. Smile

hangarrat · Wed Jan 30, 2008 10:05 pm

Just about four hours to go here on the East Coast until the big moment.

A word of advice to a.netters living on the West Coast, if you don't want the suspense ruined, stay off the tech ops forum until you've seen the episode.

I predict the Mythbusters' result is going ignite a whole new firestorm of controversy and at least another 900 posts in this thread. rotfl

sovietjet · Wed Jan 30, 2008 10:48 pm

What if there were snakes on the plane?

Boston92 · Thu Jan 31, 2008 12:19 am

Quoting HangarRat (Reply 891):
A word of advice to a.netters living on the West Coast, if you don't want the suspense ruined, stay off the tech ops forum until you've seen the episode.

Or get Directv, like me!

A346Dude · Thu Jan 31, 2008 1:26 am

Quoting Sovietjet (Reply 892):
What if there were snakes on the plane?

In this case, the instant the conveyor belt starts moving, the snakes will devour the thousands of pigeons inside the plane, which (as we all know) must fly in order for the plane to take off.

miller22 · Thu Jan 31, 2008 2:59 am

Now that it took the Mythbusters to teach us basic aerodynamics, can we please let this one die?

A346Dude · Thu Jan 31, 2008 3:02 am

Quoting Miller22 (Reply 895):
Now that it took the Mythbusters to teach us basic aerodynamics, can we please let this one die?

I don't get Discovery Channel... I assume it took off?

grandtheftaero · Thu Jan 31, 2008 3:05 am

They did it on Mythbusters Jan 30. Conveyor Belt + Plane = Plane took off.

Everyone who knows how to draw a free-body diagram dies a little everytime this topic is debated so please think about the children and CLOSE THIS THREAD.

Much better topics have been closed long before the 894th reply. Shame on the moderators for letting this go on for so long.

sovietjet · Thu Jan 31, 2008 3:55 am

Yes but Mythbusters did the "classic" scenario where the belt matches the aircraft ground speed. There is no way to test the original problem of the belt matching the wheel speed instantaneously. I didn't get to see the episode but AFAIK they were matching the plane speed. I'll watch it soon to make sure.

[Edited 2008-01-30 20:05:27]

Boston92 · Thu Jan 31, 2008 4:10 am

Quoting Sovietjet (Reply 898):
There is no way to test the original problem of the belt matching the wheel speed instantaneously

I don't believe that was the original question or the mystery. The mystery was if you have a plane with engines pushing the plane forward at (normally) 100MPH and you have a belt going the opposite direction at 100 MPH, does the plane move or does it stay put?

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