The OFFICIAL will the conveyor belt plane fly thread!!!! **UPDATE FIRST POST*** - Page 3

[ARCHIVED THREAD] - The OFFICIAL will the conveyor belt plane fly thread!!!! **UPDATE FIRST POST*** (Page 3 of 20)

Posted: 12/10/2007 8:32:34 PM EDT

[#1]

Quoted:
In the scenario, the airplane has no relative forward motion compared to a fixed object next to it. lets say a building off the side of the runway. you are on the other side of the runway (that is moving). the airplane spools up its engines and andvances to takeoff power at the same time the conveyor is keeping the airplane in the exact same spot (no relative motion to the building). The airplane is at full takeoff power and the conveyor keeps this airplane at a still spot (again no relative motion from the building behind from your spectator spot on the other side of the runway).
There is no headwind coming down the runway. It is a calm day.

The airplane will not fly. there is no headwind. The engines are turning and the wheels are spinning, and there is no relative motion to the building, but the airplane will not fly. no airspeed = no lift = no flight.

Dude . . . dude . . . have you read ANYTHING we've been saying? Your whole premise is incorrect! Therefore your arguments are moot!

Since you can't explain my simple explanation, I'll explain it another way.

Let's say you're sitting on a shopping cart. The shopping cart is on a conveyor belt. The belt begins to move backwards. But someone ahead of you is holding onto you with a rope, keeping you from moving backwards. So now you're not moving, and the wheels are spinning as the belt rushes below you. It may be bumpy, but you're not moving. The only grip the belt has on your cart is the friction of the wheels. That's easy to fight against, since these wheels are high quality and well-lubricated. The belt is traveling at 50mph, but the person holding the rope isn't having a hard time keeping you stationary. Then the person in front of you holding the rope gives you a tug. You move forward! You now have a groundspeed of 1mph, and the wheels are spinning at 51mph. The person controlling the speed of the belt sees this and he speeds up the belt to stop you. As the conveyor belt speeds up and the wheels spin faster, the friction in the wheels increases and the person has to hold on harder. But now the conveyor belt is going at 100mph, and he can still hold on. He gives another tug, and you move forwards again! The conveyor belt operator sees this and accelerates to 200mph. But the wheels aren't made for those speeds, and they tear themselves apart, and you are killed as the cart flips over and you land face-down on the speeding rubber, which instantly skins and eviscerates you. Nice going, moron.

Posted: 12/10/2007 8:33:58 PM EDT

[#2]

Quoted:

Quoted:
If the plane can move individually of the treadmill (IE, in real world without "magical" constraints), then what the hell is stopping it from moving?!

Nothing.

The story goes that an airplane is on a magical conveyor belt in place of a runway. As the airplane accelerates, the conveyor belt moves in the opposite direction, supposedly at exactly the same speed as the airplane.

Now, if we were talking about a car, the belt could easily hold it in place. And thats why this has confused so many people who are not familiar with how airplanes work. People instinctively know that a conveyor belt could hold a car in place, because it would hold a person in place, and assume that the same rules for cars and people apply to airplanes.

Obviously they don't. The car must accelerate by directing it's thrust through it's wheels and into the ground, so the motion of the ground it's in contact with is relevant. A runner must direct his thrust into the ground with his legs. Airplanes universally direct their thrust into the air, somehow, and so the motion of the ground is irrelevant.

But the no fly people somehow manage to miss this distinction. They then try to sound smart by spouting some crap about airplanes needing airflow over their wings to fly which is correct but inane. As long as they can't understand the difference between how a car moves around on the ground and how an airplane does, they sure shouldn't be listened to when they talk about how an airplane flies.

-Local

The thrust creates the forward motion, just the same as the vehicles tires or the runners shoes exert the forward motion to the ground. airplanes simply displace air. If the plane is moving at the exact same speed as the converyor belt in the opposite direction, it has no reltive motion and no relative wind. There is no airflow going over the wings which is what is required for *most* airplanes to fly (those with greater than 1:1 thrust to weight ratio can takeoff vertically and that is all due to engine power and the wings and stabs are simply there for control surfaces and stability.)
If there is no realtive wind, the wing will not generate lift. The wing has to create more than it's own weight in lift. Lets say a Regional Jet weighs 50,000 lbs. The wing has to produce more than 50,000 lbs of lift in order to get off the round. The size of the wing will determine how much weight is "carried" by each sq. in. of the wing (loading)
But in order to get lift, there has to be airflow over the wing.
In your situation, there is no airflow over the wing.

Now if there was a huge fan out in front of the conveyor that was producing a wind, thats a different story. If its a super windy day and the aircraft has a headwind that would allow the wing to generate more than its weight in lift, it will fly.

But under no circumstance will it fly if there is no wind going over the wings. its basic aerodynamics. The wheels will turn and turn until they blow, but the plane isn't leaving the ground.

You're forgetting one thing...the free-spinning wheels of the plane negate any force the rear-moving treadmill could exert on the airplane. That leaves the engines producing thrust against the air behind them (not the ground, remember?), pushing the plane forward relative to the air and generating airflow over the wings.

Think of it like this...if you could build a conveyor belt of ice and put an ice-skater on it, then give that ice-skater a rope to hold onto, as the 'ice-belt' increases in speed, is the ice skater going to have to "pull harder" on the rope to stay in place? Not measurably anyway, so that ice-skater could just as easily pull herself forward relative to, say, a knot tied in the rope when the ice-belt is turning 100 MPH as when it's standing still because the blades of the skates negate any rearward movement. So think of the belt turning 100 mph and the skater is holding onto the rope. As long as she can pull hard enough to overcome the tiny bit of resistance caused by the friction of the blades on the ice, so could a plane move forward through the air if it can overcome the small amount of friction in the wheels.

But, if the conveyor belt is running at a speed that keeps the aircraft at fixed position. ((look at my post above) for the relative to the building and you are a spectator on the other side of the moving conveyor belt runway)

There would be no relative forward motion. The tires have to turn, but if the conveyor is moving at 100 mph and the wheels are moving at 100 mph with the engines at takeoff thrust, but there is no relative forward motion, the airplane won't fly.

Posted: 12/10/2007 8:34:15 PM EDT

[#3]

Quoted:
In the scenario, the airplane has no relative forward motion compared to a fixed object next to it. lets say a building off the side of the runway. you are on the other side of the runway (that is moving). the airplane spools up its engines and andvances to takeoff power at the same time the conveyor is keeping the airplane in the exact same spot (no relative motion to the building). The airplane is at full takeoff power and the conveyor keeps this airplane at a still spot (again no relative motion from the building behind from your spectator spot on the other side of the runway).
There is no headwind coming down the runway. It is a calm day.

The airplane will not fly. there is no headwind. The engines are turning and the wheels are spinning, and there is no relative motion to the building, but the airplane will not fly. no airspeed = no lift = no flight.

Read that part in red. Stop RIGHT THERE. There is your problem. Stop, stop, stop. Alto!

The conveyor CAN NOT keep the airplane in the same spot. It could if the airplane was powered by the wheels (like a car), but on an airplane, the wheels simply spin freely. If you placed a car in neutral, strapped a jet engine on top, placed it on a conveyor that was moving backwards at 1,000,000mph, the car would move forward. You agree with this, right?

Posted: 12/10/2007 8:35:30 PM EDT

[#4]

Quoted:

Quoted:
Here's the question.

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 the opposite direction). Can the plane take off?"

No, it won't fly. it would have groundspeed as read from a GPS because the ground beneath it is moving relative to the wheels. It won't have groundspeed as read from DME.

***snip***

So the plane will not fly...at all

Unbelievable.

There is nothing to prevent the plane from moving forward. read the question again very slowly. It even states the plane "moves" movement creates air speed.

Posted: 12/10/2007 8:35:54 PM EDT

[#5]

Quoted:

Quoted:
No, it won't fly. it would have groundspeed as read from a GPS because the ground beneath it is moving relative to the wheels. It won't have groundspeed as read from DME.

It WILL have groundspeed as read from DME. I'm frankly puzzled as to WHY you think people that design airplanes for a living are full of shit.

Why do you think airplanes are driven by their wheels? WHY? Why do you keep comparing it to a car? Why don't you think the wheels on an airplane do anything other than sit there and spin freely? WHY?

airplanes are not driven at all by the wheels. and no you would not have any speed compared to a DME. it measures distance and bearing and gives a speed. if the airplane isn't moving towards or away from the DME station (VOR-DME for example), there is no groundspeed.

Posted: 12/10/2007 8:37:21 PM EDT

[#6]

Quoted:

Quoted:
No, it won't fly. it would have groundspeed as read from a GPS because the ground beneath it is moving relative to the wheels. It won't have groundspeed as read from DME.

It WILL have groundspeed as read from DME. I'm frankly puzzled as to WHY you think people that design airplanes for a living are full of shit.

Why do you think airplanes are driven by their wheels? WHY? Why do you keep comparing it to a car? Why don't you think the wheels on an airplane do anything other than sit there and spin freely? WHY?

airplanes are not driven at all by the wheels. and no you would not have any speed compared to a DME. it measures distance and bearing and gives a speed. if the airplane isn't moving towards or away from the DME station (VOR-DME for example), there is no groundspeed.

Read my last post.

Posted: 12/10/2007 8:37:49 PM EDT

[#7]

height=8

Quoted:
height=8

Quoted:
If there is no headwind (as in the converyor belt situation), the plane will not fly. It will have groundspeed, but no airspeed. Airspeed is what is necessary for an airplane to fly.

There will be airspeed. One more time, you actually disagree with people who design airplanes for a living. The airplane will move forward relative to a fixed object adjacent to the conveyor, regardless of conveyor speed. The conveyor can move backwards at 1,000,000mph, and it you nail the throttle on a Cessna, it will move forward and take off.

In the scenario, the airplane has no relative forward motion compared to a fixed object next to it. lets say a building off the side of the runway. you are on the other side of the runway (that is moving). the airplane spools up its engines and andvances to takeoff power at the same time the conveyor is keeping the airplane in the exact same spot (no relative motion to the building). The airplane is at full takeoff power and the conveyor keeps this airplane at a still spot (again no relative motion from the building behind from your spectator spot on the other side of the runway).
There is no headwind coming down the runway. It is a calm day.

The airplane will not fly. there is no headwind. The engines are turning and the wheels are spinning, and there is no relative motion to the building, but the airplane will not fly. no airspeed = no lift = no flight.

Ok IF the belt can keep the plane in the same place then no the plane wont take off. BUT the whole point is that the belt can't keep the airplane in the same place it just can't happen. So yes the way you're reading the question the plane will not take off....but in the real world where the rest of us live it would.

Posted: 12/10/2007 8:38:20 PM EDT

[#8]

Quoted:

Quoted:
No, it won't fly. it would have groundspeed as read from a GPS because the ground beneath it is moving relative to the wheels. It won't have groundspeed as read from DME.

It WILL have groundspeed as read from DME. I'm frankly puzzled as to WHY you think people that design airplanes for a living are full of shit.

Why do you think airplanes are driven by their wheels? WHY? Why do you keep comparing it to a car? Why don't you think the wheels on an airplane do anything other than sit there and spin freely? WHY?

airplanes are not driven at all by the wheels. and no you would not have any speed compared to a DME. it measures distance and bearing and gives a speed. if the airplane isn't moving towards or away from the DME station (VOR-DME for example), there is no groundspeed.

wait... wait wait wait.... say again-- you say you're a pilot...

so you have no understanding of how an airplane flies OR navigates? WOW!

Posted: 12/10/2007 8:38:25 PM EDT

[#9]

Quoted:
Holy fuck, not another one

WILL NOT FLY. (IF IT STAYS IN FIXED LOCATION)

The wheels can be spinning 10,000 RPM, but unless there is AIRFLOW moving over the wings, it will not create lift.

Unless the aircraft has a positive thrust to weight ratio with enough sheer thrust to take off strait up, the thing will not move. Or if the aircrafts speed overcomes the conveyors speed, and the aircraft starts moving.

THE PLANE NEEDS TO MOVE FOREWARDS IN ORDER TO FLY.

END IT NOW!!!

Well, that post certainly doesn't explain the solution.

Posted: 12/10/2007 8:39:12 PM EDT

[#10]

Quoted:

Quoted:
In the scenario, the airplane has no relative forward motion compared to a fixed object next to it. lets say a building off the side of the runway. you are on the other side of the runway (that is moving). the airplane spools up its engines and andvances to takeoff power at the same time the conveyor is keeping the airplane in the exact same spot (no relative motion to the building). The airplane is at full takeoff power and the conveyor keeps this airplane at a still spot (again no relative motion from the building behind from your spectator spot on the other side of the runway).
There is no headwind coming down the runway. It is a calm day.

The airplane will not fly. there is no headwind. The engines are turning and the wheels are spinning, and there is no relative motion to the building, but the airplane will not fly. no airspeed = no lift = no flight.

Read that part in red. Stop RIGHT THERE. There is your problem. Stop, stop, stop. Alto!

The conveyor CAN NOT keep the airplane in the same spot. It could if the airplane was powered by the wheels (like a car), but on an airplane, the wheels simply spin freely. If you placed a car in neutral, strapped a jet engine on top, placed it on a conveyor that was moving backwards at 1,000,000mph, the car would move forward. You agree with this, right?

No, of course not. Conveyor belts are magic.

Posted: 12/10/2007 8:40:14 PM EDT

[#11]

AeroE - you're here! THANK GOD. Will you please explain to Sniper what you do for a living, and will you PLEASE explain to him why a conveyor can't hold a plane still? For the love of God, my head is going to explode.

Posted: 12/10/2007 8:40:15 PM EDT

[#12]

Quoted:

Quoted:
If the plane can move individually of the treadmill (IE, in real world without "magical" constraints), then what the hell is stopping it from moving?!

Nothing.

The story goes that an airplane is on a magical conveyor belt in place of a runway. As the airplane accelerates, the conveyor belt moves in the opposite direction, supposedly at exactly the same speed as the airplane.

Now, if we were talking about a car, the belt could easily hold it in place. And thats why this has confused so many people who are not familiar with how airplanes work. People instinctively know that a conveyor belt could hold a car in place, because it would hold a person in place, and assume that the same rules for cars and people apply to airplanes.

Obviously they don't. The car must accelerate by directing it's thrust through it's wheels and into the ground, so the motion of the ground it's in contact with is relevant. A runner must direct his thrust into the ground with his legs. Airplanes universally direct their thrust into the air, somehow, and so the motion of the ground is irrelevant.

But the no fly people somehow manage to miss this distinction. They then try to sound smart by spouting some crap about airplanes needing airflow over their wings to fly which is correct but inane. As long as they can't understand the difference between how a car moves around on the ground and how an airplane does, they sure shouldn't be listened to when they talk about how an airplane flies.

-Local

The thrust creates the forward motion, just the same as the vehicles tires or the runners shoes exert the forward motion to the ground. airplanes simply displace air. If the plane is moving at the exact same speed as the converyor belt in the opposite direction, it has no reltive motion and no relative wind. There is no airflow going over the wings which is what is required for *most* airplanes to fly (those with greater than 1:1 thrust to weight ratio can takeoff vertically and that is all due to engine power and the wings and stabs are simply there for control surfaces and stability.)
If there is no realtive wind, the wing will not generate lift. The wing has to create more than it's own weight in lift. Lets say a Regional Jet weighs 50,000 lbs. The wing has to produce more than 50,000 lbs of lift in order to get off the round. The size of the wing will determine how much weight is "carried" by each sq. in. of the wing (loading)
But in order to get lift, there has to be airflow over the wing.
In your situation, there is no airflow over the wing.

Now if there was a huge fan out in front of the conveyor that was producing a wind, thats a different story. If its a super windy day and the aircraft has a headwind that would allow the wing to generate more than its weight in lift, it will fly.

But under no circumstance will it fly if there is no wind going over the wings. its basic aerodynamics. The wheels will turn and turn until they blow, but the plane isn't leaving the ground.

You're forgetting one thing...the free-spinning wheels of the plane negate any force the rear-moving treadmill could exert on the airplane. That leaves the engines producing thrust against the air behind them (not the ground, remember?), pushing the plane forward relative to the air and generating airflow over the wings.

Think of it like this...if you could build a conveyor belt of ice and put an ice-skater on it, then give that ice-skater a rope to hold onto, as the 'ice-belt' increases in speed, is the ice skater going to have to "pull harder" on the rope to stay in place? Not measurably anyway, so that ice-skater could just as easily pull herself forward relative to, say, a knot tied in the rope when the ice-belt is turning 100 MPH as when it's standing still because the blades of the skates negate any rearward movement. So think of the belt turning 100 mph and the skater is holding onto the rope. As long as she can pull hard enough to overcome the tiny bit of resistance caused by the friction of the blades on the ice, so could a plane move forward through the air if it can overcome the small amount of friction in the wheels.

But, if the conveyor belt is running at a speed that keeps the aircraft at fixed position. ((look at my post above) for the relative to the building and you are a spectator on the other side of the moving conveyor belt runway)

There would be no relative forward motion. The tires have to turn, but if the conveyor is moving at 100 mph and the wheels are moving at 100 mph with the engines at takeoff thrust, but there is no relative forward motion, the airplane won't fly.

what does the speed of the wheels have to do with the ability of the engines to push against the air? As has been said MULTIPLE times already, the action of the treadmill on the plane is negated by the free-spinning wheels, leaving the engines to act on the air as if the plane were at zero knots airspeed and just starting their takeoff roll.

Attach the plane to a big string and hang it from a hook so that it's not touching the ground at all. Now power up the engines. Does it move forward in relation to the hangar? YES. why? because there is no friction holding the plane in place. the wheels of the plane achieve the same effect as hanging the plane by the hook by neutralizing the rearward motion of the treadmill. The net effect is that the free spinning wheels allow the engines to push against the air behind them and move the plane forward in relation to the hangar (the wheel speed will be treadmill speed + airplane speed relative to the hangar.)

Posted: 12/10/2007 8:40:28 PM EDT

[#13]

Quoted:

Quoted:
Thank you for letting me know something i already know

You obviously didn't know that at the point in the thread where I quoted you. you learned it later in the thread and had to go back and correct yourself.
My point still stands, this idiocy will end when people quit claiming the plane won't fly.

Im sorry if i offended you. I wasn't looking at it in the right "way" (again, because of false assumptions)

I wasn't offended, I'm sorry if I made it sound like I was. I actually get a kick out of these threads. The arguments some of these goofballs come up with are hilarious.

Posted: 12/10/2007 8:42:18 PM EDT

[#14]

Quoted:

Quoted:
Here's the question.

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 the opposite direction). Can the plane take off?"

No, it won't fly. it would have groundspeed as read from a GPS because the ground beneath it is moving relative to the wheels. It won't have groundspeed as read from DME.

It WILL NOT have any airspeed. Airspeed is what you need to get off the ground. That is measured in the pitot tube(s)

Think of it as a car in neutral and a dyno hooked up. the engine doesn't even have to be running. Can you walk around the car? do you feel any airflow over the car anywhere? NO is the correct answer.

Lets take the plane in the same scenario.
Lets put a small airplane on a treadmill...same scenario as a large aircraft on a runway, just on a smaller scale.
With the engine(s) running at takeoff power and the treadmill/conveyor belt working in the opposite direction at the same speed, you walk around the airplane. do you feel any airflow over the wings? NO is the correct answer. You will feel air being displaced from the engines, but that is relative. if it is a turbojet airplane, no displaced air whatsoever is passing over the wings therefore, no lift. No air goes into the pitot tube, therefor no airspeed.
No airspeed and no lift = no flying.

With a prop airplane, the props are usually ahead of the wings. The displaced airflow would create some lift over the wings (accelerated lift) but you would have to have a C130 motor on a 172 to create enough lift to get it off the ground. And if it did, it would be so noseheavy, it would wreck anyways.

So the plane will not fly...at all

LOL....you are hilarious.

Groundspeed has NOTHING to do with a plane generating lift. the fact of the matter is, the wheels negate any force the ground can apply on the plane, so the rest of the equation is left to the engines and the air.

ETA: Have you actually WATCHED the video linked to at the top of page 2?

yes I watched the video, and the plane had forward motion which completely negates anything in the conveyor situation. In the conveyor situation, the aircraft has no relative forward motion compared on an object off of the conveyor. that means there is no airpseed. no airspeed = no flight simple as that.
And if the groundspeed is such a big factor, then forget ground speed all together.
because what you are really saying is that an airplane will takeoff with the engines pushed to full power with no relative motion. Go to the airport and watch small airplanes do their runups with the brakes on. do you see them lift off the ground? no you say? because they have no airspeed. if they aren't getting any wind over the wings, they won't fly.

Posted: 12/10/2007 8:44:08 PM EDT

[#15]

Quoted:
No, it won't fly. it would have groundspeed as read from a GPS because the ground beneath it is moving relative to the wheels. It won't have groundspeed as read from DME.

Are you fucking high?

Does the conveyor somehow cause it's GPS coordinates to change, even though the object is, according to you, stationary?

Posted: 12/10/2007 8:44:09 PM EDT

[#16]

Quoted:

Quoted:
Quoted:
Takes airflow over a wing. thats why an airplane flies. the wheels can go as fast as they want, but if there is no airflow on the wings, you ain't going no-where. youre tires will blow depending on their rating.
Its like a car on a dyno tester. the wheels are movin, but it aint going anywhere, and the spoiler on the back....yeah it aint doing jack.

Now if they provide airflow over the wing/to the engine(s) when they are running at takeoff power, then you have a different scenario.

Or if engine thrust to weight ratio is great than 1:1 and the aircraft is angled (then its a rocket, but it would fly)

But sitting on an opposite rotating conveyor belt with no relative motion, the only thing that will turn are the wheels and the motors. it takes at least somewhat of a relative forward motion for the plane to fly.

And I'm a pilot, so whoever said pilots and engineers say it'll fly, not me.

So unless I am misunderstanding the scenario, I vote it won't fly.

you either misunderstand the scenario, or misunderstand how your machine works. unlike a car on a road (or dyno), the airplane does not push against the ground to create any sort of movement. The engines push against the air which in turn causes the airplane to move forward.

You should know that an airplane can fly with zero groundspeed-- IE, if it takes 100kts of airflow over the wings to produce enough lift to overcome the weight of the aircraft, it will fly, regardless of movement across the ground. That means that if an airplane is pointed into a 100kt headwind, it will appear to hover over the ground.

The movement of the wheels are irrelevant. An airplane propels itself by pushing against the air mass, not against the ground.

You just answered your own question.

There is no headwind. The wheels will turn and you would get a relative groundspeed, but you would not get an airspeed. There is no wind in the conveyor belt scenario. With no wind, there is no lift, with no lift, there is no flight (except for those aircraft with greater than 1:1 thrust to weight ratios) which we aren't talking about.

The average airliner needs about 140 knots of airspeed give or take depending on weight...to take off.

In the conveyor situation, the wheels would turn and would have no bearing whatsoever on airspeed. there is no air going into the pitot tubes, there is no air going over the wings, let alone the control surfaces to get the airplane off the ground.

Without any air over the wings, you get no lift. Without any air over the elevator, you get no downpressure on the horizontal sbailizer which will not lift the nose of the airplane and will not create an angle of attack to get the airplane off the ground.
(all this is a mute point because there is no lift from the wing because there is no relative wind)

So answer me this one question.....WHY is there no headwind?[/quote]

because the airplane is stationary compared to a fixed object off the conveyor. that means it has no relative motion. there is no outside source of headwind, that means the plane won't fly. the airplane has no forward motion at all because the conveyor belt is working in the opposite direction at the same speed.

Posted: 12/10/2007 8:44:11 PM EDT

[#17]

Quoted:
Go to the airport and watch small airplanes do their runups with the brakes on. do you see them lift off the ground? no you say? because they have no airspeed. if they aren't getting any wind over the wings, they won't fly.

that's because their engine thrust is being overcome by the friction of the braked wheels. the forces are negated.

the force of the treadmill is negated by the movement of the wheels, leaving the force generated by the engines to act on the air around it and push the plane forward.

Posted: 12/10/2007 8:44:30 PM EDT

[#18]

Quoted:
In the conveyor situation, the aircraft has no relative forward motion compared on an object off of the conveyor.

For the love of all that is holy...

You just ignored everything I wrote. I'm...speechless.

Posted: 12/10/2007 8:45:28 PM EDT

[#19]

Quoted:
yes I watched the video, and the plane had forward motion which completely negates anything in the conveyor situation. In the conveyor situation, the aircraft has no relative forward motion compared on an object off of the conveyor. that means there is no airpseed. no airspeed = no flight simple as that.

But you are talking about a VERY specific situation, where the forward power of the engines equals the friction in the wheels, which holds the plane at 0 groundspeed on a moving belt. We're talking about if the plane COULD take off, not if it's possible to hold a plane stationary on a moving belt.

Posted: 12/10/2007 8:46:04 PM EDT

[#20]

didn't we already do 75+ pages of this?

Posted: 12/10/2007 8:46:41 PM EDT

[#21]

Quoted:

The plane will move forward just as fast as if it was sitting on an airfield...the wheels will simply be spun faster than normal.

There is one concept that you are seriously failing to see:

The movement of the conveyor is dependent upon the speed of the aircrafy. In order for the conveyor to "match the speed" of the plane, the plane must be moving. It will not appear stationary - it will be moving forward at X speed, but the wheels will be spinning at 2X speed.

How hard is this to understand? The conveyor does NOT MOVE unless the plane moves..

Posted: 12/10/2007 8:46:43 PM EDT

[#22]

Quoted:
The plane will absoluetly fly. I will scoff at those of you who think it will not when you are proven wrong.

(Hint, I'm an avid R/C flyer, and I KNOW it will take off.)

The wheels have bearings that allow them to spin freely at any speed with a negligible amount of force imparted to the airplane.

If you put a model airplane (or anything with wheels on a conveyor belt) and turn on the belt, you could hold the plane (or hot wheels car, or whatever) in place on the moving belt with your finger. The bearings reduce the friction to almost nothing. The force needed to hold it there would be a fraction of an ounce.

Compare that to the multiple ounces (and sometimes, pounds) of thrust produced by your model airplane prop, and you can easily see how the plane will take off.

maybe so with your bearing, but your r/c plane will still not fly unless it has a greater than 1:1 thrust to lift ratio. if the engine is running at full power and the conveyor is working at the exact same speed, the plane has no relative motion to something off the conveyor. and it has no headwind generated by any other source. the plane is stationary even with the wheels spinning because the conveyor is keeping it still.
won't fly.

Posted: 12/10/2007 8:46:49 PM EDT

[#23]

Quoted:

Quoted:
Here's the question.

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 the opposite direction). Can the plane take off?"

No, it won't fly. it would have groundspeed as read from a GPS because the ground beneath it is moving relative to the wheels. It won't have groundspeed as read from DME.

It WILL NOT have any airspeed. Airspeed is what you need to get off the ground. That is measured in the pitot tube(s)

Think of it as a car in neutral and a dyno hooked up. the engine doesn't even have to be running. Can you walk around the car? do you feel any airflow over the car anywhere? NO is the correct answer.

Lets take the plane in the same scenario.
Lets put a small airplane on a treadmill...same scenario as a large aircraft on a runway, just on a smaller scale.
With the engine(s) running at takeoff power and the treadmill/conveyor belt working in the opposite direction at the same speed, you walk around the airplane. do you feel any airflow over the wings? NO is the correct answer. You will feel air being displaced from the engines, but that is relative. if it is a turbojet airplane, no displaced air whatsoever is passing over the wings therefore, no lift. No air goes into the pitot tube, therefor no airspeed.
No airspeed and no lift = no flying.

With a prop airplane, the props are usually ahead of the wings. The displaced airflow would create some lift over the wings (accelerated lift) but you would have to have a C130 motor on a 172 to create enough lift to get it off the ground. And if it did, it would be so noseheavy, it would wreck anyways.

So the plane will not fly...at all

LOL....you are hilarious.

Groundspeed has NOTHING to do with a plane generating lift. the fact of the matter is, the wheels negate any force the ground can apply on the plane, so the rest of the equation is left to the engines and the air.

ETA: Have you actually WATCHED the video linked to at the top of page 2?

yes I watched the video, and the plane had forward motion which completely negates anything in the conveyor situation. In the conveyor situation, the aircraft has no relative forward motion compared on an object off of the conveyor. that means there is no airpseed. no airspeed = no flight simple as that.
And if the groundspeed is such a big factor, then forget ground speed all together.
because what you are really saying is that an airplane will takeoff with the engines pushed to full power with no relative motion. Go to the airport and watch small airplanes do their runups with the brakes on. do you see them lift off the ground? no you say? because they have no airspeed. if they aren't getting any wind over the wings, they won't fly.

EXACTLY!!!! The planes don't take off because the brakes are INCREASING the friction between the ground and the airframe to a level greater than the engines ability to create lift. Take the brakes off and it doesn't matter what the speed of the wheels is, the remaining friction is small enough that the engine will be able to push the plane forward through the air, generating airspeed and allowing the plane to achieve takeoff airspeed.

Posted: 12/10/2007 8:48:01 PM EDT

[#24]

Quoted:
AeroE - you're here! THANK GOD. Will you please explain to Sniper what you do for a living, and will you PLEASE explain to him why a conveyor can't hold a plane still? For the love of God, my head is going to explode.

Nope, I ain't sayin' one way or t'other.

I'm busy lining up property for the Helga

and the survivors.

When I had a real job, I designed stuff to kill commies, socialists, terrorists, and other ne'er do wells. Now I'm reduced to grinding through 747-8 ribs and trying to understand how the fuck anyone could think CATIA is worth a fuck, and how the hell BCA ever built an airplane without a discernible drawing tree. Fundamental crap like that.

The first thread should be out of the black hole by now. I'll check to see where the last one is, be right back -

Posted: 12/10/2007 8:49:02 PM EDT

[#25]

Quoted:

Quoted:
Here's the question.

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 the opposite direction). Can the plane take off?"

No, it won't fly. it would have groundspeed as read from a GPS because the ground beneath it is moving relative to the wheels. It won't have groundspeed as read from DME.

It WILL NOT have any airspeed. Airspeed is what you need to get off the ground. That is measured in the pitot tube(s)

Think of it as a car in neutral and a dyno hooked up. the engine doesn't even have to be running. Can you walk around the car? do you feel any airflow over the car anywhere? NO is the correct answer.

Lets take the plane in the same scenario.
Lets put a small airplane on a treadmill...same scenario as a large aircraft on a runway, just on a smaller scale.
With the engine(s) running at takeoff power and the treadmill/conveyor belt working in the opposite direction at the same speed, you walk around the airplane. do you feel any airflow over the wings? NO is the correct answer. You will feel air being displaced from the engines, but that is relative. if it is a turbojet airplane, no displaced air whatsoever is passing over the wings therefore, no lift. No air goes into the pitot tube, therefor no airspeed.
No airspeed and no lift = no flying.

With a prop airplane, the props are usually ahead of the wings. The displaced airflow would create some lift over the wings (accelerated lift) but you would have to have a C130 motor on a 172 to create enough lift to get it off the ground. And if it did, it would be so noseheavy, it would wreck anyways.

So the plane will not fly...at all

LOL....you are hilarious.

Groundspeed has NOTHING to do with a plane generating lift. the fact of the matter is, the wheels negate any force the ground can apply on the plane, so the rest of the equation is left to the engines and the air.

ETA: Have you actually WATCHED the video linked to at the top of page 2?

yes I watched the video, and the plane had forward motion which completely negates anything in the conveyor situation. In the conveyor situation, the aircraft has no relative forward motion compared on an object off of the conveyor. that means there is no airpseed. no airspeed = no flight simple as that.
And if the groundspeed is such a big factor, then forget ground speed all together.
because what you are really saying is that an airplane will takeoff with the engines pushed to full power with no relative motion. Go to the airport and watch small airplanes do their runups with the brakes on. do you see them lift off the ground? no you say? because they have no airspeed. if they aren't getting any wind over the wings, they won't fly.

What's your source for the fixed object off the belt?
Where are you getting your version of the question? It doesn't match any version I've read yet.
Again, here's the question. It has nothing about maintaining zero movement in relation to a fixed object off the belt.

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 the opposite direction). Can the plane take off?"

Posted: 12/10/2007 8:49:29 PM EDT

[#26]

Quoted:

Quoted:
No, it won't fly. it would have groundspeed as read from a GPS because the ground beneath it is moving relative to the wheels. It won't have groundspeed as read from DME.

It WILL NOT have any airspeed. Airspeed is what you need to get off the ground. That is measured in the pitot tube(s)

Think of it as a car in neutral and a dyno hooked up. the engine doesn't even have to be running. Can you walk around the car? do you feel any airflow over the car anywhere? NO is the correct answer.

Lets take the plane in the same scenario.
Lets put a small airplane on a treadmill...same scenario as a large aircraft on a runway, just on a smaller scale.
With the engine(s) running at takeoff power and the treadmill/conveyor belt working in the opposite direction at the same speed, you walk around the airplane. do you feel any airflow over the wings? NO is the correct answer. You will feel air being displaced from the engines, but that is relative. if it is a turbojet airplane, no displaced air whatsoever is passing over the wings therefore, no lift. No air goes into the pitot tube, therefor no airspeed.
No airspeed and no lift = no flying.

With a prop airplane, the props are usually ahead of the wings. The displaced airflow would create some lift over the wings (accelerated lift) but you would have to have a C130 motor on a 172 to create enough lift to get it off the ground. And if it did, it would be so noseheavy, it would wreck anyways.

So the plane will not fly...at all

That's just sofa kind we todd did.

As I said before, the only thing . . . let me repeat . . . the ONLY THING keeping the plane following the conveyor belt is the friction of the spinning wheels. That friction is a very tiny force, especially compared to the power of the engine. To keep a plane stationary with a conveyor belt with the plane's engine on full power, you would have to accelerate the treadmill AMAZINGLY, MIND-BOGGLINGLY rapidly for that small force to keep up. In a fraction of a second, the wheels would be spinning so fast that they'd pull themselves apart.

In a realistic scenario, you would not be able to do that. No matter how hard you tried, the tiny force of the wheel friction would just not be strong enough to keep the wheels glued to the belt.

Live with it.

so then the entire scenario is out of the question because the conveyor did not keep the airplane from moving forward along the range of the conveyor belt. The whole thing would be scrapped then. In the scenario, the conveyor keeps the airplane from having any forward motion (it stays in the exact same spot even though the wheels and converyor are turning).

you aren't talking about the same thing.

live with it

Posted: 12/10/2007 8:49:48 PM EDT

[#27]

Quoted:

airplanes are not driven at all by the wheels. and no you would not have any speed compared to a DME. it measures distance and bearing and gives a speed. if the airplane isn't moving towards or away from the DME station (VOR-DME for example), there is no groundspeed.

You understand that airplanes are not driven by thier wheels, but still suppose that the airplane will not move off the belt. Why? What is keeping the airplane on the belt?

Put another way, what counter acts the force of the engine? Lets look at an f15 again.

Lets say one engine isn't running today, to make it even more apparent, and the pilot wants to show off what hot shit the Eagle is to all those little Viper drivers. So he throttles that one engine right up to full afterburner, cranking out all 15,000 lbs of force he can.

Think about 15,000 pounds of force. Thats 7 and a half tons of force. Thats more then 2 elephants. In order to hold that aircraft in place you need to exert that 15,000 lbs of force in the other direction.

So where does all that counteracting force come from, and how do you apply it to the aircraft? Now, I'll accept that this is a magical conveyor belt, and it could produce that much force. But how does it act on that aircraft? Through it's three wheels, of course.

Each wheel probably rests on several bearings, which ride on a shaft or two. Lets suppose that the bearings are just so-so. With out the math involved, I figure that all three wheels together might produce a retarding force/friction of about 10 pounds (I'm not including static friction, which would be quite a bit higher). So thats 15,000 lbs minus 10, or 14,990 net pounds of thrust acting on the air frame.

So, how does the airplane not move?

-Local

Posted: 12/10/2007 8:49:56 PM EDT

[#28]

Quoted:
because the airplane is stationary compared to a fixed object off the conveyor. that means it has no relative motion. there is no outside source of headwind, that means the plane won't fly. the airplane has no forward motion at all because the conveyor belt is working in the opposite direction at the same speed.

O
M
F
G
!

You can't be this dumb. Have you not read one word we've been writing for the last two or three pages?

The conveyor belt CANNOT work against the plane, except as far as the tiny amount of friction in the wheels will allow! You are living in a fantasy world! Come back to our world! Things make much more sense here!

All the conveyor belt does is spin the wheels. In normal circumstances, when the plane throttles up and begins to speed down the runway, what are the wheels doing? Spinning! The aircraft is MADE to move forward as the wheels are spinning backwards!

Posted: 12/10/2007 8:52:34 PM EDT

[#29]

Quoted:
so then the entire scenario is out of the question because the conveyor did not keep the airplane from moving forward along the range of the conveyor belt. The whole thing would be scrapped then. In the scenario, the conveyor keeps the airplane from having any forward motion (it stays in the exact same spot even though the wheels and converyor are turning).

you aren't talking about the same thing.

live with it

No . . . you see, I live on a planet called Earth. In my world, your scenario is impossible. I believe that it is a waste of time to wonder if something impossible is possible.

Now, your scenario IS possible if the machines are specifically made for this sort of thing. For example, wheels that are made to have a lot of friction, so that the conveyor belt actually has something to work with. As the speed goes up, the wheels will produce more and more friction. Eventually, at a certain speed, and assuming the wheels aren't spinning fast enough to rip apart, the engine will not have enough power to fight against the friction, and then any more speed you add to the belt will make the vehicle move backwards.

But a plane's wheels, assuming they are in OK condition, simply do not have enough friction for this to ever work. Their wheels would self-destruct before the friction equaled the engine's thrust.

Posted: 12/10/2007 8:53:03 PM EDT

[#30]

Quoted:
Sniper7, you have to be trolling. There's no way in hell you're this dense. After it's been explained to you countless times, you insist that there will be no air over the wings, when it is an absolute fact that there will be. Know why? Because the airplane will move forward relative to a stationary object adjacent to the conveyor, regardless of conveyor speed.

Put your car on a treadmill, leave it in neutral, and strap a jet engine on top. Let the conveyor move backwards at any speed you like (let's make it 1,000mph) Do you not agree that the car will move forward, albeit with the wheels turning VERY quickly?

in the scenario, the airplane, even after putting in all its power has no forward motion (if the converyor keeps the plane in the same relative spot.

sorry man, but not trolling and speaking of dense, take a look at your avatar, then look in the mirror.

the plane won't fly if there is no relative forward motion and there is no outside force generating a headwind

Posted: 12/10/2007 8:54:19 PM EDT

[#31]

Quoted:

Quoted:

But the conveyor is moving at the exact same speed as the aircraft which means the aircraft looks as if it is still.

take a small plane and put it on a treadmill. the plane is moving just as fast as the treadmill in opposite directions. the speed cancel each other out. the wheels are turning, but the entire airplane has no relative motion (you could walk around the treadmill while the wheels and conveyor belt are turning)

plane won't fly because there is no airspeed. read my other posts for details

Please, quit flying now. You obviously have NO clue about how your AC functions and it would seem that you are a danger to your general surroundings...

really? and what exactly do you do for a living because I hope it is nothing more than picking up dog shit in the neighborhood park because thats about the only thing you have a clue about.

Posted: 12/10/2007 8:54:38 PM EDT

[#32]

Quoted:

Quoted:
Sniper7, you have to be trolling. There's no way in hell you're this dense. After it's been explained to you countless times, you insist that there will be no air over the wings, when it is an absolute fact that there will be. Know why? Because the airplane will move forward relative to a stationary object adjacent to the conveyor, regardless of conveyor speed.

Put your car on a treadmill, leave it in neutral, and strap a jet engine on top. Let the conveyor move backwards at any speed you like (let's make it 1,000mph) Do you not agree that the car will move forward, albeit with the wheels turning VERY quickly?

in the scenario, the airplane, even after putting in all its power has no forward motion (if the converyor keeps the plane in the same relative spot.

sorry man, but not trolling and speaking of dense, take a look at your avatar, then look in the mirror.

the plane won't fly if there is no relative forward motion and there is no outside force generating a headwind

You keep refusing to answer the question posed to you over and over and over again Sniper. HOW does the belt keep the plane in place....Answer that question...HOW?

Posted: 12/10/2007 8:55:48 PM EDT

[#33]

Quoted:

Quoted:
Sniper7, you have to be trolling. There's no way in hell you're this dense. After it's been explained to you countless times, you insist that there will be no air over the wings, when it is an absolute fact that there will be. Know why? Because the airplane will move forward relative to a stationary object adjacent to the conveyor, regardless of conveyor speed.

Put your car on a treadmill, leave it in neutral, and strap a jet engine on top. Let the conveyor move backwards at any speed you like (let's make it 1,000mph) Do you not agree that the car will move forward, albeit with the wheels turning VERY quickly?

in the scenario, the airplane, even after putting in all its power has no forward motion (if the converyor keeps the plane in the same relative spot.

sorry man, but not trolling and speaking of dense, take a look at your avatar, then look in the mirror.

the plane won't fly if there is no relative forward motion and there is no outside force generating a headwind

You are pulling the "no relative motion" out of your ass. The conveyor can not put enough rearward force on the plane, via the interaction with the planes free-spinning wheels, to keep the plane form moving.

Your statement that a plane can not fly without air flow over the wing is correct.

Your statement that the conveyor will keep the plane form moving forward, the basis for your entire disagreement, is flat-out false.

Posted: 12/10/2007 8:55:52 PM EDT

[#34]

Quoted:

so then the entire scenario is out of the question because the conveyor did not keep the airplane from moving forward along the range of the conveyor belt. The whole thing would be scrapped then. In the scenario, the conveyor keeps the airplane from having any forward motion (it stays in the exact same spot even though the wheels and converyor are turning).

you aren't talking about the same thing.

live with it

Sniper-

No conveyor belt, however magical or however good the control system, could keep a typical airplane in place. The amount of force it would have to exert through the airplanes wheels is simply too high. The wheels would have to be spun at hundreds of thousands of rpm, perhaps higher, before the belt could actually counteract the thrust of even a small engine. Long before that the bearings or tires would have failed. And that makes sense. The whole goal of the wheels and bearing is to reduce as far as possible the friction between the ground and airplane.

The fact is that there is no way to hold that airplane in place by spinning it's tires.

-Local

Posted: 12/10/2007 8:55:57 PM EDT

[#35]

Please answer the following question...

Quoted:

the plane won't fly if there is no relative forward motion and there is no outside force generating a headwind

Posted: 12/10/2007 8:57:21 PM EDT

[#36]

Quoted:
in the scenario, the airplane, even after putting in all its power has no forward motion (if the converyor keeps the plane in the same relative spot.

sorry man, but not trolling and speaking of dense, take a look at your avatar, then look in the mirror.

the plane won't fly if there is no relative forward motion and there is no outside force generating a headwind

One more time, before I give up and fully realize that I'm being played here, as part of a well executed joke:

In what world can a conveyor keep an airplane still? How fast would a conveyor have to move backwards to hold even a Cessna in one place, when it's at full throttle?

Posted: 12/10/2007 8:58:30 PM EDT

[#37]

Quoted:

Quoted:

But the conveyor is moving at the exact same speed as the aircraft which means the aircraft looks as if it is still.

take a small plane and put it on a treadmill. the plane is moving just as fast as the treadmill in opposite directions. the speed cancel each other out. the wheels are turning, but the entire airplane has no relative motion (you could walk around the treadmill while the wheels and conveyor belt are turning)

plane won't fly because there is no airspeed. read my other posts for details

Please, quit flying now. You obviously have NO clue about how your AC functions and it would seem that you are a danger to your general surroundings...

really? and what exactly do you do for a living because I hope it is nothing more than picking up dog shit in the neighborhood park because thats about the only thing you have a clue about.

Really? I know the plane takes off. Your insults are meaningless because you refuse to see reality. So I reiterate. Stop flying so you don't kill yourself or others.

Posted: 12/10/2007 8:58:31 PM EDT

[#38]

Quoted:

Quoted:

the plane won't fly if there is no relative forward motion and there is no outside force generating a headwind

AHAHAHAHAHAHAHA!!!!!!!

It makes sense! If free-spinning wheels can hold a plane back, it could certainly hold back a Saturn V!

My god, we may be entering a whole new realm of physics, all thanks to sniper7!

Posted: 12/10/2007 8:59:40 PM EDT

[#39]

www.ar15.com/forums/topic.html?b=1&f=5&t=626727

www.ar15.com/forums/topic.html?b=1&f=5&t=635149

www.ar15.com/forums/topic.html?b=1&f=5&t=634624

I couldn't find the first thread, but that's not necessary anyway.

Posted: 12/10/2007 8:59:51 PM EDT

[#40]

Quoted:

Quoted:
Takes airflow over a wing. thats why an airplane flies. the wheels can go as fast as they want, but if there is no airflow on the wings, you ain't going no-where. youre tires will blow depending on their rating.
Its like a car on a dyno tester. the wheels are movin, but it aint going anywhere, and the spoiler on the back....yeah it aint doing jack.

Now if they provide airflow over the wing/to the engine(s) when they are running at takeoff power, then you have a different scenario.

Or if engine thrust to weight ratio is great than 1:1 and the aircraft is angled (then its a rocket, but it would fly)

But sitting on an opposite rotating conveyor belt with no relative motion, the only thing that will turn are the wheels and the motors. it takes at least somewhat of a relative forward motion for the plane to fly.

And I'm a pilot, so whoever said pilots and engineers say it'll fly, not me.

So unless I am misunderstanding the scenario, I vote it won't fly.

The plane will move forward just as fast as if it was sitting on an airfield...the wheels will simply be spun faster than normal.
The thrust moving the plane foreward comes from the PROP...the wheels are just freewheeling.

It is NOTHING like a car on a dyno...the WHEELS move the car.
A rocket powered car on a dyno would shoot right off the end of the dyno.

But the conveyor is moving at the exact same speed as the aircraft which means the aircraft looks as if it is still.

take a small plane and put it on a treadmill. the plane is moving just as fast as the treadmill in opposite directions. the speed cancel each other out. the wheels are turning, but the entire airplane has no relative motion (you could walk around the treadmill while the wheels and conveyor belt are turning)

plane won't fly because there is no airspeed. read my other posts for details

Read my last post to see how wrong you are, but I'll just say again and put it another way . . . the plane's propellor is what moves it forward. If the conveyor belt is moving backwards, what is pulling the plane backwards? Only the friction of the wheels. That's the only grip the belt has on the plane. The propellor can EASILY fight against that and move forwards.

You are stuck on the wheels. You are absolutely right that if the conveyor belt is moving as fast as the wheels, the plane isn't moving. Your problem is that your whole PREMISE is wrong. YOU CAN'T GET THE CONVEYOR BELT TO FIGHT AGAINST THE ENGINE!

very true, you can't get the conveyor belt to finght against the engines.
but, then let me ask you, why the fuck then do airplanes have fucking wheels in the first place? they obviously don't need them. why the hell don't delta and untied put conveyor belts on the fucking ramps?
I'll tell you why, because they are smarter than all of you who think the plane will actually fly.

the engines create the thrust, the wheels allow the aircraft to roll. that rolling forward motion is generated by the thrust of the engines displacing air (doesn't matter if it is turbine or prop). the air that is displaced is compressed and exerted backwards pushing the airplane forward. the forward motionis transmitter through the air by the engines, but made easier (friction) by the wheels. a rolling object is much easier to move that an airplane without landing gear (watch a geared up airplane try to taxi) and see how far he gets with all the fucking power pushing all the air....not going to happen.

you have to have the tires to reduce frition so you can gain airspeed so you can get air over the wings so you can fly.

Posted: 12/10/2007 9:01:15 PM EDT

[#41]

Quoted:

Quoted:
Sniper7, you have to be trolling. There's no way in hell you're this dense. After it's been explained to you countless times, you insist that there will be no air over the wings, when it is an absolute fact that there will be. Know why? Because the airplane will move forward relative to a stationary object adjacent to the conveyor, regardless of conveyor speed.

Put your car on a treadmill, leave it in neutral, and strap a jet engine on top. Let the conveyor move backwards at any speed you like (let's make it 1,000mph) Do you not agree that the car will move forward, albeit with the wheels turning VERY quickly?

in the scenario, the airplane, even after putting in all its power has no forward motion (if the converyor keeps the plane in the same relative spot.

sorry man, but not trolling and speaking of dense, take a look at your avatar, then look in the mirror.

the plane won't fly if there is no relative forward motion and there is no outside force generating a headwind

Wow, that's awesome! Someone who has fallen in Retard Quicksand getting all haughty at someone who mentions maybe he should just swim out of it.

ETA: DANGIT! I FORGOT THAT I WAS TRYING NOT TO TAG THIS THREAD! CURSE YOU GD!

Posted: 12/10/2007 9:01:41 PM EDT

[#42]

You all managed to do it again. The worst part is, a lot of you are the same people as in the other nine thousand threads. I hope you have your posts saved in a file, please tell me you don't spend your time doing this again and again.

There is a special room in hell where all people do is discuss this question. All of you that choose to do this in the mortal world are a special breed of fucked up.

btw- the fucking plane flies!

Posted: 12/10/2007 9:02:57 PM EDT

[#43]

Quoted:

very true, you can't get the conveyor belt to finght against the engines.
but, then let me ask you, why the fuck then do airplanes have fucking wheels in the first place? they obviously don't need them.

Because they figured power-sliding into the terminal wasn't a good idea.

hy the hell don't delta and untied put conveyor belts on the fucking ramps?
I'll tell you why, because they are smarter than all of you who think the plane will actually fly.

Because wheels are cheaper than conveyor belts as long as a runway.

Next stupid questions.

Posted: 12/10/2007 9:03:13 PM EDT

[#44]

Quoted:
very true, you can't get the conveyor belt to finght against the engines.
but, then let me ask you, why the fuck then do airplanes have fucking wheels in the first place? they obviously don't need them. why the hell don't delta and untied put conveyor belts on the fucking ramps?
I'll tell you why, because they are smarter than all of you who think the plane will actually fly.

the engines create the thrust, the wheels allow the aircraft to roll. that rolling forward motion is generated by the thrust of the engines displacing air (doesn't matter if it is turbine or prop). the air that is displaced is compressed and exerted backwards pushing the airplane forward. the forward motionis transmitter through the air by the engines, but made easier (friction) by the wheels. a rolling object is much easier to move that an airplane without landing gear (watch a geared up airplane try to taxi) and see how far he gets with all the fucking power pushing all the air....not going to happen.

you have to have the tires to reduce frition so you can gain airspeed so you can get air over the wings so you can fly.

Excellent post, and I might as well have written it myself. You actually get it, but somehow conclude that a plane with free spinning wheels is unable to move forward on a conveyor. Man, you're like --> <-- this close to getting it.

Posted: 12/10/2007 9:03:29 PM EDT

[#45]

Quoted:

Quoted:
Takes airflow over a wing. thats why an airplane flies. the wheels can go as fast as they want, but if there is no airflow on the wings, you ain't going no-where. youre tires will blow depending on their rating.
Its like a car on a dyno tester. the wheels are movin, but it aint going anywhere, and the spoiler on the back....yeah it aint doing jack.

Now if they provide airflow over the wing/to the engine(s) when they are running at takeoff power, then you have a different scenario.

Or if engine thrust to weight ratio is great than 1:1 and the aircraft is angled (then its a rocket, but it would fly)

But sitting on an opposite rotating conveyor belt with no relative motion, the only thing that will turn are the wheels and the motors. it takes at least somewhat of a relative forward motion for the plane to fly.

And I'm a pilot, so whoever said pilots and engineers say it'll fly, not me.

So unless I am misunderstanding the scenario, I vote it won't fly.

The plane will move forward just as fast as if it was sitting on an airfield...the wheels will simply be spun faster than normal.
The thrust moving the plane foreward comes from the PROP...the wheels are just freewheeling.

It is NOTHING like a car on a dyno...the WHEELS move the car.
A rocket powered car on a dyno would shoot right off the end of the dyno.

But the conveyor is moving at the exact same speed as the aircraft which means the aircraft looks as if it is still.

take a small plane and put it on a treadmill. the plane is moving just as fast as the treadmill in opposite directions. the speed cancel each other out. the wheels are turning, but the entire airplane has no relative motion (you could walk around the treadmill while the wheels and conveyor belt are turning)

plane won't fly because there is no airspeed. read my other posts for details

Read my last post to see how wrong you are, but I'll just say again and put it another way . . . the plane's propellor is what moves it forward. If the conveyor belt is moving backwards, what is pulling the plane backwards? Only the friction of the wheels. That's the only grip the belt has on the plane. The propellor can EASILY fight against that and move forwards.

You are stuck on the wheels. You are absolutely right that if the conveyor belt is moving as fast as the wheels, the plane isn't moving. Your problem is that your whole PREMISE is wrong. YOU CAN'T GET THE CONVEYOR BELT TO FIGHT AGAINST THE ENGINE!

very true, you can't get the conveyor belt to finght against the engines.
but, then let me ask you, why the fuck then do airplanes have fucking wheels in the first place? they obviously don't need them. why the hell don't delta and untied put conveyor belts on the fucking ramps?
I'll tell you why, because they are smarter than all of you who think the plane will actually fly.

the engines create the thrust, the wheels allow the aircraft to roll. that rolling forward motion is generated by the thrust of the engines displacing air (doesn't matter if it is turbine or prop). the air that is displaced is compressed and exerted backwards pushing the airplane forward. the forward motionis transmitter through the air by the engines, but made easier (friction) by the wheels. a rolling object is much easier to move that an airplane without landing gear (watch a geared up airplane try to taxi) and see how far he gets with all the fucking power pushing all the air....not going to happen.

you have to have the tires to reduce frition so you can gain airspeed so you can get air over the wings so you can fly.

And all of this, while technically correct, doesn't explain how you think the belt can prevent the airplane from achieving forward airspeed, regardless of the speed of the belt or the wheels.

Posted: 12/10/2007 9:04:07 PM EDT

[#46]

Quoted:

Quoted:
Read my last post to see how wrong you are, but I'll just say again and put it another way . . . the plane's propellor is what moves it forward. If the conveyor belt is moving backwards, what is pulling the plane backwards? Only the friction of the wheels. That's the only grip the belt has on the plane. The propellor can EASILY fight against that and move forwards.

You are stuck on the wheels. You are absolutely right that if the conveyor belt is moving as fast as the wheels, the plane isn't moving. Your problem is that your whole PREMISE is wrong. YOU CAN'T GET THE CONVEYOR BELT TO FIGHT AGAINST THE ENGINE!

very true, you can't get the conveyor belt to finght against the engines.
but, then let me ask you, why the fuck then do airplanes have fucking wheels in the first place? they obviously don't need them. why the hell don't delta and untied put conveyor belts on the fucking ramps?
I'll tell you why, because they are smarter than all of you who think the plane will actually fly.

the engines create the thrust, the wheels allow the aircraft to roll. that rolling forward motion is generated by the thrust of the engines displacing air (doesn't matter if it is turbine or prop). the air that is displaced is compressed and exerted backwards pushing the airplane forward. the forward motionis transmitter through the air by the engines, but made easier (friction) by the wheels. a rolling object is much easier to move that an airplane without landing gear (watch a geared up airplane try to taxi) and see how far he gets with all the fucking power pushing all the air....not going to happen.

you have to have the tires to reduce frition so you can gain airspeed so you can get air over the wings so you can fly.

I really can't believe I'm arguing about this. You are either very blind or incredibly stupid. I'm NOT kidding, and I'm not being rude. I'm being factual.

Your post has nothing to do with my post. I can't even respond. You have no clue what we are saying, but you THINK you do.

Posted: 12/10/2007 9:05:08 PM EDT

[#47]

I'm off to make a thread pic just for this thread... brb....

Posted: 12/10/2007 9:05:53 PM EDT

[#48]

Quoted:

Quoted:
In the scenario, the airplane has no relative forward motion compared to a fixed object next to it. lets say a building off the side of the runway. you are on the other side of the runway (that is moving). the airplane spools up its engines and andvances to takeoff power at the same time the conveyor is keeping the airplane in the exact same spot (no relative motion to the building). The airplane is at full takeoff power and the conveyor keeps this airplane at a still spot (again no relative motion from the building behind from your spectator spot on the other side of the runway).
There is no headwind coming down the runway. It is a calm day.

The airplane will not fly. there is no headwind. The engines are turning and the wheels are spinning, and there is no relative motion to the building, but the airplane will not fly. no airspeed = no lift = no flight.

Dude . . . dude . . . have you read ANYTHING we've been saying? Your whole premise is incorrect! Therefore your arguments are moot!

Since you can't explain my simple explanation, I'll explain it another way.

Let's say you're sitting on a shopping cart. The shopping cart is on a conveyor belt. The belt begins to move backwards. But someone ahead of you is holding onto you with a rope, keeping you from moving backwards. So now you're not moving, and the wheels are spinning as the belt rushes below you. It may be bumpy, but you're not moving. The only grip the belt has on your cart is the friction of the wheels. That's easy to fight against, since these wheels are high quality and well-lubricated. The belt is traveling at 50mph, but the person holding the rope isn't having a hard time keeping you stationary. Then the person in front of you holding the rope gives you a tug. You move forward! You now have a groundspeed of 1mph, and the wheels are spinning at 51mph. The person controlling the speed of the belt sees this and he speeds up the belt to stop you. As the conveyor belt speeds up and the wheels spin faster, the friction in the wheels increases and the person has to hold on harder. But now the conveyor belt is going at 100mph, and he can still hold on. He gives another tug, and you move forwards again! The conveyor belt operator sees this and accelerates to 200mph. But the wheels aren't made for those speeds, and they tear themselves apart, and you are killed as the cart flips over and you land face-down on the speeding rubber, which instantly skins and eviscerates you. Nice going, moron.

same thing an airplane would do. the tires would blow, you wouldn't fly and more than likely everyone would be killed in the crash and post crash fire. nice going moron...you told me absolutely nothing. the engines, just like your guy pulling the rope, spool up, but the conveyor keeps the cart in the same spot. if the converyor keeps the airplane in the same spot, it won't fly. the wheels can turn 200 mph, but you have no airspeed because you are not moving foward.

Posted: 12/10/2007 9:06:36 PM EDT

[#49]

When a dozen people with experience are telling you that you are a retard, a wise person would listen. Then again, most retards aren't wise.

Posted: 12/10/2007 9:07:39 PM EDT

[#50]

I think everyone is getting confused here.
Conveyor belt, not a tread mill.

[ARCHIVED THREAD] - The OFFICIAL will the conveyor belt plane fly thread!!!! **UPDATE FIRST POST*** (Page 3 of 20)

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