That plane, and it taking off.

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PurdueRy

Lifer
Nov 12, 2004
13,837
4
0
Originally posted by: newmachineoverlord
Once the pilot fires up the engines, the plane moves forward at pretty much the usual speed relative to the ground--and more importantly the air--regardless of how fast the conveyor belt is moving backward. This generates lift on the wings, and the plane takes off. All the conveyor belt does is, as you correctly conclude, make the plane's wheels spin madly.
The obvious flaw here is that the above is basically assuming that the plane is not resting on the conveyor. Imagine the planes engines are off. In this case, the conveyor pushes the plane backwards until it falls off the conveyor. Turning the engines on just allows the plane to keep pace with the conveyor, meaning that the plane is completely stationary relative to the ground and the air, but has a forward velocity relative to the belt.

Thus it depends how the problem is phrased. If the conveyor is moving at a rate that keeps the plane stationary relative to the wind, there will be no lift, and hence, no takeoff. A plane must have forward motion relative to the air in order to take off. If it is only moving relative to the conveyor belt, and not the wind, as the problem implies, there is no lift and it cannot takeoff.

I should point out some caveats with this interpretation: It assumes that the engine does not directly force air over the wings. This assumption is probably valid for most jet engines, but probably not for propeller based light aircraft. In the case of such light aircraft where the propellor not only generates thrust but also forces air to pass over the wings, a completely vertical takeoff is possible.

edited typo

The conveyor can only rotate the wheels...it cannot push the plane backwards
 

BrokenVisage

Lifer
Jan 29, 2005
24,771
14
81
I love how everyone on here saying yes is suddenly an avionics expert in addition to being a computer geek.

Too bad we can't simulate this in Flight Simulator to prove you guys wrong.
 

PurdueRy

Lifer
Nov 12, 2004
13,837
4
0
Originally posted by: BrokenVisage
I love how everyone on here saying yes is suddenly an avionics expert in addition to being a computer geek.

Too bad we can't simulate this in Flight Simulator to prove you guys wrong.

it doesn't take an avionics expert. Basic physics will do...draw the FBD, you will have your answer
 

middlehead

Diamond Member
Jul 11, 2004
4,573
2
81
Originally posted by: jagec
I'm sorry, but physics > democracy. We could "democratically" vote to invent FTL travel, but it wouldn't suddenly appear as a result.
It wouldn't? DAMN IT!

I've got some petitions to recall.
 

DanTMWTMP

Lifer
Oct 7, 2001
15,908
19
81
Originally posted by: deathkoba
You're all stupid. I'm right, you're wrong and there's nothing that can convince me or other real pilots (with their heads screwed in right) otherwise.

The plane will take off only if it's engine can generate enough thrust to push the plane even harder than it already is doing, (which is what's keeping it visually stationary in the first place) to the point where there is enough airspeed for take off. So the real answer is YES or NO depending on the performance of the engine and how fast that conveyor belt is moving and whether or not the conveyor belt is adjusting it's speed in realtime as the plane's engine makes adjustments. That plus other environmental factors that affect flight performance directly or indirectly. It's common sense folks.

taken from what you said in the other thread:
Originally posted by: deathkoba
You people are retarded. It will not take off as the sole lift mechanism (the wings) will not be getting any airflow. The engines only push the aircraft so that enough air can flow over the wings. Only then will the aircraft achieve any level of lift. I'm a private pilot with instrument license.

Now if there is enough headwind, even when the plane is visually stationary, it's possible that the headwind itself can push the plane up a bit but it would be very uncontrolled and will simply flip the plane over.



ahem.. let me take a moment while I laugh at you.

LOL!!!!!!!!! HAHAHAHA!!!! MAJI!?!?!??!.....you seroius?!?! no way!?

puahahahhahah1!!!!



my god.

another post you made:

Hm...let's simply put it this way....

The aircraft will not take off until ENOUGH HEADWIND is generated in ANY way. The aircraft's flight performance is entirely dependent on airspeed, not groundspeed. Couple that with common sense and well..enough already. Maybe I woke up in the twilight zone.


of course enough headwind needs to be generated, but that's because the plane IS MOVING FOWARD relative to the air and to anyone standing still looking at the plane. As you said, the ground has nothing to do with it. exactly. that's why the wheels will just freespin. If the conveyor belt does anything to the plane, it's because it's moving at an extreme, INFINITE speeds to to a plane that tries to even move very slowly. That of course requires a ton of energy, impractical to prove a LOGICAL point, and physically not possible to set up a senario where the conveyor belt goes fast enough to provide enough resistance to stop the plane.

like you said, this is just common sense right? yup.

logically, using common sense (as you say), it'll take about an infinite amount of energy to even stop a plane going at less than 1 MPH on the ground.

the question is anyways, impossible mathematically (given the wording/explanation of the question). How can the control system that makes the conveyor belt move according to the plane's wheel speed (or plane speed) "know" at what speed to move in the first place? The plane first moves 10 mph, than some time later, it moves 10 mph backwards? Machine logically, some time must have progressed to make this remotely possible.

So, then, let's have the conveyor belt move at infinite speeds as soon as the plane even moves less than one cm. Then maybe, given these ideal conditions that the plane wheels have a great deal of friction, and the conveyor belt has infinite power, stability, rigidity, and every physical part of the conveyor belt is ideally indestrutable, then yes, the plane may stop moving relative to the airspeed.






if you're a pilot, then explain this: A seaplane (given that there is no wind), going up against the flow of the tide, is on sleds, yet at some point, will still move 10 mph relative to anyone looking @ it and the airspeed, yet today there's a ton of current at sea. The sea's current going against the plane is about, let's say, 15 mph, yet the plane is still moving 10 mph forward, taxing normally. wtf is going on eh?!

A sled plane, taking off in Alaska is merely sliding across the ice...


bleh, i don't need to discuss this further. Get your headchecked deathkoba, and everyone else who thinks the plane won't fly. ugh.
 

cKGunslinger

Lifer
Nov 29, 1999
16,408
57
91
Originally posted by: deathkoba
You're all stupid. I'm right, you're wrong and there's nothing that can convince me or other real pilots (with their heads screwed in right) otherwise.

The fact that a review board has deemed you cabable of flying aircraft scares the bejeebus out of me.

And no, not for your lack of knowledge in this specific example, but for your total misunderstanding of basic physics and logic, coupled with your thick-headed, "I can't possibly be wrong" attitude. You watched too much Top Gun as a kid, didn't you? :eek:
 

thirdlegstump

Banned
Feb 12, 2001
8,713
0
0
Originally posted by: cKGunslinger
Originally posted by: deathkoba
You're all stupid. I'm right, you're wrong and there's nothing that can convince me or other real pilots (with their heads screwed in right) otherwise.

The fact that a review board has deemed you cabable of flying aircraft scares the bejeebus out of me.

And no, not for your lack of knowledge in this specific example, but for your total misunderstanding of basic physics and logic, coupled with your thick-headed, "I can't possibly be wrong" attitude. You watched too much Top Gun as a kid, didn't you? :eek:

Well they did call me Maverick.
 

cKGunslinger

Lifer
Nov 29, 1999
16,408
57
91
Originally posted by: deathkoba
Originally posted by: cKGunslinger
Originally posted by: deathkoba
You're all stupid. I'm right, you're wrong and there's nothing that can convince me or other real pilots (with their heads screwed in right) otherwise.

The fact that a review board has deemed you cabable of flying aircraft scares the bejeebus out of me.

And no, not for your lack of knowledge in this specific example, but for your total misunderstanding of basic physics and logic, coupled with your thick-headed, "I can't possibly be wrong" attitude. You watched too much Top Gun as a kid, didn't you? :eek:

Well they did call me Maverick.

You're destined to share Goose's fate. :(
 

thirdlegstump

Banned
Feb 12, 2001
8,713
0
0
Originally posted by: DanTMWTMP
Originally posted by: deathkoba
You're all stupid. I'm right, you're wrong and there's nothing that can convince me or other real pilots (with their heads screwed in right) otherwise.

The plane will take off only if it's engine can generate enough thrust to push the plane even harder than it already is doing, (which is what's keeping it visually stationary in the first place) to the point where there is enough airspeed for take off. So the real answer is YES or NO depending on the performance of the engine and how fast that conveyor belt is moving and whether or not the conveyor belt is adjusting it's speed in realtime as the plane's engine makes adjustments. That plus other environmental factors that affect flight performance directly or indirectly. It's common sense folks.

taken from what you said in the other thread:
Originally posted by: deathkoba
You people are retarded. It will not take off as the sole lift mechanism (the wings) will not be getting any airflow. The engines only push the aircraft so that enough air can flow over the wings. Only then will the aircraft achieve any level of lift. I'm a private pilot with instrument license.

Now if there is enough headwind, even when the plane is visually stationary, it's possible that the headwind itself can push the plane up a bit but it would be very uncontrolled and will simply flip the plane over.



ahem.. let me take a moment while I laugh at you.

LOL!!!!!!!!! HAHAHAHA!!!! MAJI!?!?!??!.....you seroius?!?! no way!?

puahahahhahah1!!!!



my god.

another post you made:

Hm...let's simply put it this way....

The aircraft will not take off until ENOUGH HEADWIND is generated in ANY way. The aircraft's flight performance is entirely dependent on airspeed, not groundspeed. Couple that with common sense and well..enough already. Maybe I woke up in the twilight zone.


of course enough headwind needs to be generated, but that's because the plane IS MOVING FOWARD relative to the air and to anyone standing still looking at the plane. As you said, the ground has nothing to do with it. exactly. that's why the wheels will just freespin. If the conveyor belt does anything to the plane, it's because it's moving at an extreme, INFINITE speeds to to a plane that tries to even move very slowly. That of course requires a ton of energy, impractical to prove a LOGICAL point, and physically not possible to set up a senario where the conveyor belt goes fast enough to provide enough resistance to stop the plane.

like you said, this is just common sense right? yup.

logically, using common sense (as you say), it'll take about an infinite amount of energy to even stop a plane going at less than 1 MPH on the ground.

the question is anyways, impossible mathematically (given the wording/explanation of the question). How can the control system that makes the conveyor belt move according to the plane's wheel speed (or plane speed) "know" at what speed to move in the first place? The plane first moves 10 mph, than some time later, it moves 10 mph backwards? Machine logically, some time must have progressed to make this remotely possible.

So, then, let's have the conveyor belt move at infinite speeds as soon as the plane even moves less than one cm. Then maybe, given these ideal conditions that the plane wheels have a great deal of friction, and the conveyor belt has infinite power, stability, rigidity, and every physical part of the conveyor belt is ideally indestrutable, then yes, the plane may stop moving relative to the airspeed.






if you're a pilot, then explain this: A seaplane (given that there is no wind), going up against the flow of the tide, is on sleds, yet at some point, will still move 10 mph relative to anyone looking @ it and the airspeed, yet today there's a ton of current at sea. The sea's current going against the plane is about, let's say, 15 mph, yet the plane is still moving 10 mph forward, taxing normally. wtf is going on eh?!

A sled plane, taking off in Alaska is merely sliding across the ice...


bleh, i don't need to discuss this further. Get your headchecked deathkoba, and everyone else who thinks the plane won't fly. ugh.

YOU need to get your head checked. I didn't say it won't fly, I said it will fly given certain parameters given the situation. You're either misinterperating what I'm saying or simply have no idea how things work in aviation. All said, it's VERY likely that there's a big misunderstanding and you actually do agree with me but you simply cannot word things right (or me not wording things right).
 

cKGunslinger

Lifer
Nov 29, 1999
16,408
57
91
Originally posted by: deathkoba
YOU need to get your head checked. I didn't say it won't fly, I said it will fly given certain parameters given the situation. You're either misinterperating what I'm saying or simply have no idea how things work in aviation. All said, it's VERY likely that there's a big misunderstanding and you actually do agree with me but you simply cannot word things right (or me not wording things right).

Did you, or did you not say this in the original thread:
Originally posted by: deathkoba
You people are retarded. It will not take off as the sole lift mechanism (the wings) will not be getting any airflow. The engines only push the aircraft so that enough air can flow over the wings. Only then will the aircraft achieve any level of lift. I'm a private pilot with instrument license.

If this is what you believe, then you are dead wrong - simple as that. You can throw in as many minute and extraneous details as you want to try and rationalize your misguided opinion, but the simply fact remains is that a rolling conveyor belt will no hinder the forward motion provided by the jet's engine and the plane *will* move forward, creating lift, and take off.

Logic + Physics > You
 

JDrake

Banned
Dec 27, 2005
10,246
0
0
If it is a propeller airplane, TECHNICALLY, it COULD take off from the wind provided by the propellers, but it would take a lot more than normal, considering that is not the main factor in a plane taking off
technically: it could
realistically: no
 

thirdlegstump

Banned
Feb 12, 2001
8,713
0
0
Originally posted by: cKGunslinger
Originally posted by: deathkoba
YOU need to get your head checked. I didn't say it won't fly, I said it will fly given certain parameters given the situation. You're either misinterperating what I'm saying or simply have no idea how things work in aviation. All said, it's VERY likely that there's a big misunderstanding and you actually do agree with me but you simply cannot word things right (or me not wording things right).

Did you, or did you not say this in the original thread:
Originally posted by: deathkoba
You people are retarded. It will not take off as the sole lift mechanism (the wings) will not be getting any airflow. The engines only push the aircraft so that enough air can flow over the wings. Only then will the aircraft achieve any level of lift. I'm a private pilot with instrument license.

If this is what you believe, then you are dead wrong - simple as that. You can throw in as many minute and extraneous details as you want to try and rationalize your misguided opinion, but the simply fact remains is that a rolling conveyor belt will no hinder the forward motion provided by the jet's engine and the plane *will* move forward, creating lift, and take off.

Logic + Physics > You

Wrong but it's not worth explaining as you cannot possibly understand how all of these different factors and possibilities (missing but required parameters in OP question) relate to flight performance. It might not even be a jet although that would make no difference. Sorry but you're WRONG.
 

Mo0o

Lifer
Jul 31, 2001
24,227
3
76
This does not shine a positive light on the intelligence of roughly 33% of the ATOT population
 

cKGunslinger

Lifer
Nov 29, 1999
16,408
57
91
Originally posted by: deathkoba
Wrong but it's not worth explaining as you cannot possibly understand how all of these different factors and possibilities (missing but required parameters in OP question) relate to flight performance. It might not even be a jet although that would make no difference. Sorry but you're WRONG.

Smarter people than you have admitting to be wrong before. You should try it, it won't kill you. :thumbsup:
 

PurdueRy

Lifer
Nov 12, 2004
13,837
4
0
Originally posted by: joedrake
If it is a propeller airplane, TECHNICALLY, it COULD take off from the wind provided by the propellers, but it would take a lot more than normal, considering that is not the main factor in a plane taking off
technically: it could
realistically: no

1. The problem specifies the engines have to be in the back of the plane

2. That's not necessary as it will take off anyway.
 

PurdueRy

Lifer
Nov 12, 2004
13,837
4
0
Originally posted by: deathkoba
Originally posted by: cKGunslinger
Originally posted by: deathkoba
YOU need to get your head checked. I didn't say it won't fly, I said it will fly given certain parameters given the situation. You're either misinterperating what I'm saying or simply have no idea how things work in aviation. All said, it's VERY likely that there's a big misunderstanding and you actually do agree with me but you simply cannot word things right (or me not wording things right).

Did you, or did you not say this in the original thread:
Originally posted by: deathkoba
You people are retarded. It will not take off as the sole lift mechanism (the wings) will not be getting any airflow. The engines only push the aircraft so that enough air can flow over the wings. Only then will the aircraft achieve any level of lift. I'm a private pilot with instrument license.

If this is what you believe, then you are dead wrong - simple as that. You can throw in as many minute and extraneous details as you want to try and rationalize your misguided opinion, but the simply fact remains is that a rolling conveyor belt will no hinder the forward motion provided by the jet's engine and the plane *will* move forward, creating lift, and take off.

Logic + Physics > You

Wrong but it's not worth explaining as you cannot possibly understand how all of these different factors and possibilities (missing but required parameters in OP question) relate to flight performance. It might not even be a jet although that would make no difference. Sorry but you're WRONG.

How does that make HIM wrong?
 

Armitage

Banned
Feb 23, 2001
8,086
0
0
Originally posted by: deathkoba
You're all stupid. I'm right, you're wrong and there's nothing that can convince me or other real pilots (with their heads screwed in right) otherwise.

The plane will take off only if it's engine can generate enough thrust to push the plane even harder than it already is doing, (which is what's keeping it visually stationary in the first place) to the point where there is enough airspeed for take off. So the real answer is YES or NO depending on the performance of the engine and how fast that conveyor belt is moving and whether or not the conveyor belt is adjusting it's speed in realtime as the plane's engine makes adjustments. That plus other environmental factors that affect flight performance directly or indirectly. It's common sense folks.

The fact is that rolling resistance is already a small part of the drag that an aircraft has to overcome to take off. The big pieces are aerodynamic drag and simply accelerating the mass of the aircraft to takeoff speed.

On top of that, rolling resistance is almost independent of speed. Spinning the wheels on your Cessna at 140 knots on the conveyor instead of 70 knots on a normal runway takes only a very small amount more power.

It will takeoff.
 

thirdlegstump

Banned
Feb 12, 2001
8,713
0
0
Originally posted by: cKGunslinger
Originally posted by: deathkoba
Wrong but it's not worth explaining as you cannot possibly understand how all of these different factors and possibilities (missing but required parameters in OP question) relate to flight performance. It might not even be a jet although that would make no difference. Sorry but you're WRONG.

Smarter people than you have admitting to be wrong before. You should try it, it won't kill you. :thumbsup:

But that would make no difference to fact would it? I would admit I'm wrong if I have somehow developed some kind of neurological disorder over the years.

There are way too many missing parameters to the question to provide an educated answer. The answer could be yes, no or maybe so I provided the base of parameters necessary to make take off possible.

I am not leaning towards either because there is not even info in the OP.
 

Kenazo

Lifer
Sep 15, 2000
10,429
1
81
It won't take off. It wasn't really a physics problem so much as an impossible problem.
 

cKGunslinger

Lifer
Nov 29, 1999
16,408
57
91
Originally posted by: deathkoba

But that would make no difference to fact would it? I would admit I'm wrong if I have somehow developed some kind of neurological disorder over the years.

There are way too many missing parameters to the question to provide an educated answer. The answer could be yes, no or maybe so I provided the base of parameters necessary to make take off possible.

I am not leaning towards either because there is not even info in the OP.

LOL. I freely admit than a plane on a giant conveyor belt could experience several problems, not the least of which is getting slightly turned off-center and generating friction of the side-walls of the wheels and cause the whole thing to flip over. But that still doesn't explain this:

Originally posted by: deathkoba
You people are retarded. It will not take off as the sole lift mechanism (the wings) will not be getting any airflow. The engines only push the aircraft so that enough air can flow over the wings. Only then will the aircraft achieve any level of lift. I'm a private pilot with instrument license.

The simply fact is that you didn't think there would be any forward momemtum due to the converyor belt running in the opposite direction as the wheels. You were wrong. Get over it. You are looking like an even bigger moron for not simply saying "Oops, I was wrong on that point."
 

thirdlegstump

Banned
Feb 12, 2001
8,713
0
0
Originally posted by: cKGunslinger
Originally posted by: deathkoba

But that would make no difference to fact would it? I would admit I'm wrong if I have somehow developed some kind of neurological disorder over the years.

There are way too many missing parameters to the question to provide an educated answer. The answer could be yes, no or maybe so I provided the base of parameters necessary to make take off possible.

I am not leaning towards either because there is not even info in the OP.

LOL. I freely admit than a plane on a giant conveyor belt could experience several problems, not the least of which is getting slightly turned off-center and generating friction of the side-walls of the wheels and cause the whole thing to flip over. But that still doesn't explain this:

Originally posted by: deathkoba
You people are retarded. It will not take off as the sole lift mechanism (the wings) will not be getting any airflow. The engines only push the aircraft so that enough air can flow over the wings. Only then will the aircraft achieve any level of lift. I'm a private pilot with instrument license.

The simply fact is that you didn't think there would be any forward momemtum due to the converyor belt running in the opposite direction as the wheels. You were wrong. Get over it. You are looking like an even bigger moron for not simply saying "Oops, I was wrong on that point."

? The airfoils will not get any airflow. I THINK it was originally stated that the engine would be in the back no? Correct me if I'm wrong on that.

My statement above was a conditional statement given certain circumstances which I think you might've omitted just to prove your point. It may not have been in the same post however.

There IS forward momentum given any level of engine power applied even if the plane appeared to be still or even moving backwards. Am I incorrect here?