Airplane on the Conveyor Belt - Page 2 - Politics and War Forum

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Re: Airplane on the Conveyor Belt
Thursday, March 04, 2010 9:26 PM on j-body.org
What causes the plane to remain stationary if it's on a treadmill? If you say the wheels they you're wrong because the wheels only support the plane, they don't provide any part of the motion. The thrust is completely independent of the treadmill (and wheels) and therefore the treadmill will not stop forward motion of the plane. The plane will continue to accelerate until airspeed is sufficient for lift and then the plane will take off.

If the plane were using it's wheels to attain speed for takeoff I would agree it would never take off, but it isn't. Another variation is if you're looking at the question in the sense that the speed of the treadmill increases so much as to exert enough force on the wheels and bearings to prevent forward motion which is not how I interpret the question.







Re: Airplane on the Conveyor Belt
Thursday, March 04, 2010 9:46 PM on j-body.org
i might of misunderstood what you just posted what i took from that was you don't know how to interpret the OP's question

if you are running at 7mph on a treadmill running at 6mph you will run off the treadmill, thus the speed of the treadmill must be equal to the speed of the jet's thrust. no matter how fast you turn the speed up you are not getting air to flow under the wings and around the plane. there for it is not possible to lift a jet off of a convoyer belt.



Re: Airplane on the Conveyor Belt
Thursday, March 04, 2010 10:51 PM on j-body.org
Some of you are making this way more complicated then it is.

Forget about the fan for a second..... If you made a huge ass treadmill the size of a runway that could handle a plane landing or taking of on it..... a plane would be able to take off or land on it just fine..... the only problem would be that you couldnt have the tread mill running when the planes parking brakes where set or when it was taxiing on or off of it.

On take off..... you wouldnt see a difference if it wherent on a tread mill, but on landing the plane would just stop in a shorter distance once on the ground (assuming its using wheel brakes instead of reverse thrusters)

OK now for you people that just had to bring a giant F-ing fan into the equation LOL. If you could produce enough wind speed against the plane equal or greater to the air speed required for the plane to take of, yes it could leave the ground... its not the forward momentum that creates lift, the the air going over the air foils... (think of how a kite work and instead of a string holding it in one place, the power from the engines are doing it) although the aerodynamics of a plane are a bit different then a kite, im just simplifying. And yes one the plane got high enough that the fan wasnt blowing on it anymore it would come crashing down...... thats why if you actually had a real head wind that fast it could be maintained it would just be dangerouse as all hell being airborn with an air speed of 100 knots but a land speed of 0.

Some of you really need to read this


Quote:

A. Air approaching the top surface of the wing is compressed into the air above it as it moves upward. Then, as the top surface curves downward and away from the airstream, a low-pressure area is developed and the air above is pulled downward toward the back of the wing.

B. Air approaching the bottom surface of the wing is slowed, compressed and redirected in a downward path. As the air nears the rear of the wing, its speed and pressure gradually match that of the air coming over the top. The overall pressure effects encountered on the bottom of the wing are generally less pronounced than those on the top of the wing.

C. Lift component

D. Net force

E. Drag component

I actually studied this crap as a kid,





Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 2:05 AM on j-body.org
Josh wrote:

i might of misunderstood what you just posted what i took from that was you don't know how to interpret the OP's question

if you are running at 7mph on a treadmill running at 6mph you will run off the treadmill, thus the speed of the treadmill must be equal to the speed of the jet's thrust. no matter how fast you turn the speed up you are not getting air to flow under the wings and around the plane. there for it is not possible to lift a jet off of a conveyor belt.
the question has been worded different ways, but the way the OP worded it is the airplane must reach 100mph to take off and the conveyor would be running 100mph opposite direction. In this scenario the ground and airspeed of the plane would be 100mph but the wheel speed would be 200mph (which has no bearing on takeoff)

The original question that started this debate years ago was worded differently in that the conveyor sped up to match the speed of the airplane which is another vague way of asking the question as it can be interpreted different ways. the only way the conveyor would have any affect on the airplane is through the wheels and wheel bearings which wouldn't be able to produce enough friction to slow the plane due to the thrust of the engines.

Your analogy is flawed in that the thrust of the runner is developed directly against the treadmill whereas the plane's thrust is irrelevant of it's contact with the treadmill

If someone were on a skateboard on a treadmill with a speed of 10mph, you could push on the person to get them to move forward at 1 mph and they would move forward even if you increased the treadmill speed to ll mph. same as the plane, the thrust of the engine would move the plane forward even though the speed of the treadmill increased. Ground speed would increase, treadmill speed would increase and wheel speed would increase by 2x the amount of the other two.

Weebel wrote:

OK now for you people that just had to bring a giant F-ing fan into the equation LOL. If you could produce enough wind speed against the plane equal or greater to the air speed required for the plane to take of, yes it could leave the ground... its not the forward momentum that creates lift, the the air going over the air foils... (think of how a kite work and instead of a string holding it in one place, the power from the engines are doing it) although the aerodynamics of a plane are a bit different then a kite, im just simplifying. And yes one the plane got high enough that the fan wasnt blowing on it anymore it would come crashing down...... thats why if you actually had a real head wind that fast it could be maintained it would just be dangerouse as all hell being airborn with an air speed of 100 knots but a land speed of 0.
I don't think anyone was trying to say that they wanted to put a fan in front of the plane. I could be wrong though.

I studied the Bernoulli effect in Aerospace Engineering also, so I'm not just spouting off.


The bottom line is: Can an airplane on a conveyor develop forward motion due to thrust as the conveyor speeds up to match the planes ground speed. If the answer is yes, the plane takes off. If the answer is no, the plane doesn't
From my point of view the treadmill has minimal effect upon the motion of the airplane due to the thrust being separate from the wheels and thus the plane can achieve forward motion.






Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 6:10 AM on j-body.org
from what i got from the OP was you have a convoyer belt as long as the plane, the plane is on the convoyer belt which speeds up with the plane, think of it like when you get your car's dynoed, thats pretty much a treadmill for cars. what happens when you increase the speed of the car? the dyno keeps up and the car has no foward movement. im not saying its the same because planes arnt driven by wheels as we all know. but its a good example

so even with thrusters being a differnt part of the equation there will still be no air movement around the jet, for the people that don't know the concept behind a wing. the foils have actuators on them making them go lower on take off and landing than when they are in the air for crusing speeds. this creates a pocket of air below both wings, when you get a pocket of air it provides you with lift add that lift with speed and you can get off the ground.

think of my spolier for example, people all the time call it a wing and i have to correct them, the "wings" on my two deck spoiler are facing the opposit direction of an airplanes, thus instead of providing lift, they provide downforce. same concept as with a planes wing providing lift to take off, my spoiler provides that same pocket of air to force me to the ground. (not like i ever get fast enough to actually use it!! lol!)

so again, no wind speed no take off.



Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 6:26 AM on j-body.org
It's nowhere near the same thing as a dyno

What prevents the plane from going forward?







Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 6:28 AM on j-body.org
And address the person on a skateboard scenario with someone else pushing them. Would they move forward or not?






Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 6:42 AM on j-body.org
Labotomi wrote:

It's nowhere near the same thing as a dyno

And address the person on a skateboard scenario with someone else pushing them. Would they move forward or not?


how is this not like a dyno? same principal car has acceleration doesn't move anywhere because the drum is spinning in the opposite direction.

not if you kept the speed of the treadmill the same as the wheels on the skateboard. when you say the wheels are there for support you are correct, however the wheels must be kept the same speed on the conveyor belt which is the same size as the plane, otherwise you would drive off the treadmill.

if you have ever been to an airport with the conveyor belts on the floor moving the SAME direction as you are, you start walking your speed is increased to almost a run. if the plane was on a conveyor belt moving the SAME direction as the plane i can see the plane taking off in shorter distances.

in this case, the conveyor is moving in the OPPOSITE direction of the plane, thus keeping the plane at a standstill with no air movement.

if you can, run in place right now and see if you feel wind around your face. you won't because you are not moving forward but staying in the same place.

if you had more room on the conveyor belt and kept it at a lower speed then the plane's thrusters i would not see the point, you would be working twice as hard to make enough wind speed for the jet to take off.

example

on sold ground thrusters make 100% movement power at normal take off conditions the plane would leave the runway as normal.


on moving ground, thrusters still make 100% movement power, however with the ground moving in the OPPOSITE direction you are moving the wheels at 2x normal conditions, if the thrusters are producing say 100mph on the ground, with the treadmill going 50mph in the opposite direction you will only have the plane moving forward at 50mph and the wheels are spinning at 200mph. there for taking twice the amount of ground to provide enough lift to take off.

thats IF the thrusters can move enough wind speed around the wings to provide lift.



Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 3:20 PM on j-body.org
it's not like a dyno because the car uses the wheels to provide propulsion whereas a plane doesn't need wheels for propulsion. All of your arguments use something with ground/treadmill contact providing the means of propulsion or thrust and thus do not apply. It's a totally different situation.

for a plane to remain motionless on a moving treadmill it would only have to provide enough thrust to overcome the friction in the wheel bearings even if the treadmill were going 100mph the plane would not have to provide the thrust necessary to move it 100mph forward to accomplish this. If you increased the treadmill speed to 200mph, only slightly more thrust would be necessary to keep the plane stationary. Any additional thrust provided by the plane would result in forward motion no matter what the treadmill speed.


Anyway, I'm bored with this topic just as I was a year ago. Argue all you want with whoever will listen, but I'm done.






Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 4:06 PM on j-body.org
good because you are wrong and ignorant if you don't listen to anyone besides your self,

Quote:

how is this not like a dyno? same principal car has acceleration doesn't move anywhere because the drum is spinning in the opposite direction.


PRINCIPAL is the same the convoyer belt MUST keep up with the wheel motion of the jet. the wheels of a jet are not driven by a transmission, the wheels are driven by foward motion from the thrusters, for the plane to not run off the convoyer belt, the convoyer belt must keep up with the wheel speed of the jet. there for if the wheel speed of the jet (driven by the thrusters sense you seem to have issues grasping this) and the speed of the convoyer belt are the same. there for you do not move, when you don't move you don't move air around the wings, (refer to the post where i told you how wings work to create a pocket of air providing lift)

so explain to me your thought process on how the jet would have enough airspeed moving still.



Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 7:03 PM on j-body.org
PRINCIPAL is the person who was in charge of the school you flunked.

I've listened to and had a rebuttal to every argument you've made and been civil about it.
Just look at the dyno argument. How can you possibly say that it's the same principle(PAL)? When you say the wheels are driven by the thrusters are you saying directly driven or indirectly by movement of the plane?

I fully understand how a plane develops thrust and lift. I have 4 semester hours of aerospace engineering (I know that's not a lot) where I would like to think I learned a few things since I did pass the class.

We both have our opinions. Try not to get so worked up when someone disagrees with you.







Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 10:32 PM on j-body.org
Lambotomi I wasnt talking down to you I was just saying the people that dont understand should read that link...

JOSH.... your wrong on this one man.... and I dont think I can explain it any better then Labotomi has.

Dude... think about it for a second... when a plane takes of and is flying in the air.... the wheels arnt touching a damn thing but it keeps moving forward because of the propeller or jet engines pushing against the air (neutonian physics play a role too but Im not gunna go into it).... When a plane is still on teh ground the same thing is moving the plane forward that moves it forward in the air... the wheels have nothing to do with mooving the plane on the ground or not.

Going back to the skateboard thing... lets say you turn a treadmill all the way up.... you can kneel down next to the treadmil and hold a scateboard on the treadmil withought it going anywhere with the wheels turning on it like crazy, and even with the treadmill all the way up... you can still fling the skateboard off the front of the treadmil because your standing in non moving ground.... Its the same idea.... because the plane wouldnt have to act against the treadmill, just the atmosphere to move forward.





Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 10:41 PM on j-body.org
your post are full of fail, go ahead and rag on the fact i used the wrong form of a word good job.

what you fail at here is comprehension,

the drum spins the same speed as a wheel on a dyno. you speed up the car the drum spins faster same concept with the conveyor belt idea, the conveyor would speed up with the planes wheel speed keeping it on the conveyor belt. the wheels are being driven by the thrust of the turbines.

as i am trying to explain the car on a dyno will not go anywhere, same as a plane on a conveyor belt. i don't see how you could have knowledge over planes and not understand this if you are still confused because you lack the will power to think this through before your posts, ill draw a picture for you.



Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 10:50 PM on j-body.org
Don't you people have ANYTHING better to do?





Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 10:50 PM on j-body.org
A car on a dyno doesnt go anywhere for one reason and one reason only..... ITS STRAPPED THE HELL DOWN

If it wherent it would go flying off the dyno... but that doesnt have anything to do with the plane thing.

Dude your just looking at this thing from the wrong angle.... instead of looking at it from the ground up, think of it from the air down....

OK the wheels on a shopping cars arnt powered at all (like the wheels on a plane)... but you can push it around just fine.... now if you put that shopping cart on a tread mill, you could hold the cart in place standing behind the treadmil, and if you wanted to, you could give it a good push and push it off the front of the treadmil... (assuming it would clear the bar in the front that is) because your not on the tread mil.

Think of your feet on the standing ground as the air around the plane the engines push against.





Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 10:51 PM on j-body.org
Weebel wrote:

Lambotomi I wasnt talking down to you I was just saying the people that dont understand should read that link...

JOSH.... your wrong on this one man.... and I dont think I can explain it any better then Labotomi has.

Dude... think about it for a second... when a plane takes of and is flying in the air.... the wheels arnt touching a damn thing but it keeps moving forward because of the propeller or jet engines pushing against the air (neutonian physics play a role too but Im not gunna go into it).... When a plane is still on teh ground the same thing is moving the plane forward that moves it forward in the air... the wheels have nothing to do with mooving the plane on the ground or not.

Going back to the skateboard thing... lets say you turn a treadmill all the way up.... you can kneel down next to the treadmil and hold a scateboard on the treadmil withought it going anywhere with the wheels turning on it like crazy, and even with the treadmill all the way up... you can still fling the skateboard off the front of the treadmil because your standing in non moving ground.... Its the same idea.... because the plane wouldnt have to act against the treadmill, just the atmosphere to move forward.


maybe i should of worded my responce better,

while a plane is being propelled by a jet on non moving ground the wheels are in contact with the ground/ the wheels play a key part in the jet taking off untill the plane is moving fast enough to use the air thats flowing around it to provide lift.

you have a jet thats 40 ft long,
you have a conveyor belt that is the same size as the jet.
you have the conveyor belt moving the same speed as the wheels, which are being propelled by the turbines
because the speed of the jet and the speed of the conveyor are the same, the jet will not have wind speed
again no windspeed no lift no fly.

sorry guys im sure on this one.



Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 10:52 PM on j-body.org
Guess I got my answer.





Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 10:55 PM on j-body.org
here is the real question, why not just turn the conveyor around have it facing foward and make the plane take off in shorter distances?



Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 11:16 PM on j-body.org
Is this really still being discussed?..........



Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 11:22 PM on j-body.org
no, your posting here because the dates on the posts are wrong

please contact dave and have him change the dates so no one else gets confused and wants to argue with logic.





Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 11:35 PM on j-body.org
The wheels are not powered by the engines, they are not powered at all.... your just over thinking this too much LOL

And I gotta go, I have to see a man about an R1 tomorrow.... but hopefully the guy witht he R6 calls me back first and has the title, because if he does, im gunna go look at that one instead.

(R1 is 5 years older and he hasnt gotton the title yet)

I'll argue more with ya later

In the mean time, just try to understand why im right LOL.






Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 11:40 PM on j-body.org
Weebel wrote:

The wheels are not powered by the engines, they are not powered at all.... your just over thinking this too much LOL.


Exactly, it's simple, extremely simple.

I wish this would just die.... I thought it would after Mythbusters dedicated an entire show to it...



Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 11:44 PM on j-body.org
ugh weeble im going to shove cheese pie in your face

"driven by thrusters" meaning

wheels go round and round due to the thrusters providing foward motion thus the wheels are moving!

=/



Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 11:47 PM on j-body.org
But the wheels take power to turn...





Re: Airplane on the Conveyor Belt
Friday, March 05, 2010 11:51 PM on j-body.org
Truth,,,from consequences wrote:

But the wheels take power to turn...


im to drunk right now, are you arguing with what i just posted or agreeing?



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