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2008-01-30 19:51:39
Ganko_06
Laughter with an S
+167|6643|Camoran's Paradise

BlackKoala wrote:

Vilham wrote:

Reject_Wolf wrote:

There simply needs to be a force lifting the plane. That force is created by the forward velocity creating a lifting force against the air.
Yes but the myth states the plane must be stationary over the ground, therefore there is no forward force and therefore no lift.
Show me the fucknig myth that says the planes must stay stationary?  The original one, from like 2005 or whatever.
To my understanding, this was parameters were that the plane was generating the a forward force equal to the backward force of the conveyor.

If that's not true, than no; a conveyor belt would have not affect on a plane taking off IFF in overcame the pull of belt.

PeoNinja wrote:

Ganko_06 wrote:

PeoNinja wrote:

Mythbusters just aired the show and its busted  the plane took off
a planes wheels are merely a mechanism to reduce friction (it would take a massive amount of force, not to mention cause enormous damage to the plane, to let it drag along the ground on its belly). They have nothing to do with propulsion.  Infact, there is very little difference between the idea of a plane taking off of a conveyor belt, and a seaplane launching from the water.
Actually this is far from the idea of a seaplane.  The seaplane has to move forward and generate airflow over its wings just like any other plane.
The theory about the treadmill is that the plane DOES NOT MOVE with respect to the ground; \iIts positive thrust matches the negative pull by the treadmill thus canceling each other out leaving the plane in the same spot with its wheels spinning.  The only airflow being generated is by the propeller but that is a negligible amount since almost all of it is over the fuselage.  THERE IS NO AIRFLOW OVER THE WINGS.

0 Airflow = 0 Lift
did you missed the small scale experiment? An actual conveyor belt, not a giant potato sack pulled by a pick up, and it was the same thing, the plane move forward.
No, I saw it and what I saw was a bit inconclusive.  It appeared that the plane pulled itself forward along the treadmill for a short distance before making a brief flight.
Still proves nothing.
2008-01-30 19:52:13
Vilham
Say wat!?
+580|6764|UK

Flaming_Maniac wrote:

I'm pretty sure 95% of us understand the physics of it, the interpretation of the problem is where things go south.
Indeed.
2008-01-30 19:52:18
Locoloki
I got Mug 222 at Gritty's!!!!
+216|6638|Your moms bedroom

Vilham wrote:

DesertFox- wrote:

Vilham wrote:


Yes but the myth states the plane must be stationary over the ground, therefore there is no forward force and therefore no lift.
A plane can't be stationary like a car can though, because the plane isn't sending power to the wheels to do so.
Ofc it can. Until the plane is off the ground its wheels are supporting its weight. Without lift the plane is a giant motor with small wheels, just like a jet car eg the fastest cars in the world.. note how they DONT have power to the wheels... If that forward velocity is matched by a backwards velocity there is no movement.

Or are you trying to say the forward thrust is greater than the speed the wheels might turn, if you are. FUCKING DUR. Way to state the obvious. That means its dragging its wheels. And the myth has NOTHING to do with wheels, its all about forward thrust and negative thrust.
if you put wings on a car that could fly, you are correct, the plane would not move in the scenario

however, a plane doesnt work like a car, its power is generated from its propellors which have nothing to do with the ground
2008-01-30 19:52:38
DesertFox-
The very model of a modern major general
+794|6682|United States of America

Flaming_Maniac wrote:

I'm pretty sure 95% of us understand the physics of it, the interpretation of the problem is where things go south.
To a great degree, that's true. I don't think we've stayed on a standardized problem yet. I see the words speed, thrust, velocity all being used interchangeably.
2008-01-30 19:53:42
Ganko_06
Laughter with an S
+167|6643|Camoran's Paradise

Flaming_Maniac wrote:

I'm pretty sure 95% of us understand the physics of it, the interpretation of the problem is where things go south.
It would appear that way.
2008-01-30 19:53:49
Vilham
Say wat!?
+580|6764|UK

Locoloki wrote:

Vilham wrote:

DesertFox- wrote:

A plane can't be stationary like a car can though, because the plane isn't sending power to the wheels to do so.
Ofc it can. Until the plane is off the ground its wheels are supporting its weight. Without lift the plane is a giant motor with small wheels, just like a jet car eg the fastest cars in the world.. note how they DONT have power to the wheels... If that forward velocity is matched by a backwards velocity there is no movement.

Or are you trying to say the forward thrust is greater than the speed the wheels might turn, if you are. FUCKING DUR. Way to state the obvious. That means its dragging its wheels. And the myth has NOTHING to do with wheels, its all about forward thrust and negative thrust.
if you put wings on a car that could fly, you are correct, the plane would not move in the scenario

however, a plane doesnt work like a car, its power is generated from its propellors which have nothing to do with the ground
NOTE JET CAR. Jet cars do not provice movement to the wheels, they have massive aircraft jets that push them on free rolling wheels.

You guys dont seem to realise that the wheels on a plane are not totally free rolling, im pretty sure there is a MASSIVE ammount of friction between the wheels bearings.

Last edited by Vilham (2008-01-30 19:56:08)

2008-01-30 19:54:12
Fredrik
i hate you all
+201|6647|Norway

Flaming_Maniac wrote:

I'm pretty sure 95% of us understand the physics of it, the interpretation of the problem is where things go south.
No, i'm 100% sure that's where people get confused.

If the plane is stationary, will the treadmill move, at all?

Last edited by Fredrik (2008-01-30 19:54:25)

2008-01-30 19:56:58
Locoloki
I got Mug 222 at Gritty's!!!!
+216|6638|Your moms bedroom
this is why the first 2 threads got closed

but that was before this scenario to this very question was shown on a tv episode and proven that the plane would take off when the pilot himself, stated that he thought the plane would not move, but to his amazement (and im sure to a lot of other peoples) the plane "took off like it normally did"

Last edited by Locoloki (2008-01-30 19:59:00)

2008-01-30 19:57:43
Vilham
Say wat!?
+580|6764|UK
indeed. Blackkoala still has yet to realise the very simple statement that Flaming just put forward. not to mention he doesnt actually pose a position he just flames others as idiots... lol

Last edited by Vilham (2008-01-30 19:58:11)

2008-01-30 19:57:55
RAIMIUS
You with the face!
+244|6712|US
It is because the plane does not remain stationary (in relation to the ground).  The treadmill would have to create enough force to counteract the propulsion of the aircraft.  Spinning wheels have a very low coefficient of friction.  Therefore, the treadmill would have to go REALLY fast to counteract the thrust (when F(thust)=F(friction) the plane remains stationary).  So, it is hard to keep the plane stationary.  I think people are assuming that the F(friction) will be the frictional force of dragging the plane...which it is not.
2008-01-30 19:58:13
BlackKoala
Member
+215|6323
noone else wants to come flame away, too bad.  i was hoping to start a huge flame war, didn't work as planned.
2008-01-30 19:58:34
ATG
Banned
+5,233|6527|Global Command
I'm annoyed it's still open.

Chuy closed my thread about it even though the debate was good.

Doesn't that pretty much say it all?
2008-01-30 19:59:24
Ganko_06
Laughter with an S
+167|6643|Camoran's Paradise

BlackKoala wrote:

i dont even think this vilham numbnuts understand the premise on why the plane moves.  it is therefore worthless to argue with him, and we may now all point and laugh.
Keep it serious.  Just because you can't convey you point to make other people understand doesn't mean resorting to childish behavior.
If you want to participate in this discussion, keep arguing on a respectable level.
2008-01-30 19:59:53
Vilham
Say wat!?
+580|6764|UK

RAIMIUS wrote:

It is because the plane does not remain stationary (in relation to the ground).  The treadmill would have to create enough force to counteract the propulsion of the aircraft.  Spinning wheels have a very low coefficient of friction.  Therefore, the treadmill would have to go REALLY fast to counteract the thrust (when F(thust)=F(friction) the plane remains stationary).  So, it is hard to keep the plane stationary.  I think people are assuming that the F(friction) will be the frictional force of dragging the plane...which it is not.
Indeed. The myth states that treadmill counteracts the propulsion of the the aircraft. Therefore  F(thust)=F(friction) the plane remains stationary.
2008-01-30 20:00:12
nukchebi0
Пушкин, наше всё
+387|6322|New Haven, CT
The unclear nature of the problem makes the debate rather pointless.
2008-01-30 20:01:15
Flaming_Maniac
prince of insufficient light
+2,490|6705|67.222.138.85

ATG wrote:

I'm annoyed it's still open.

Chuy closed my thread about it even though the debate was good.

Doesn't that pretty much say it all?
Don't worry, I don't think this thread will get through another 50 posts.
2008-01-30 20:06:07
mcminty
Moderating your content for the Australian Govt.
+879|6719|Sydney, Australia
yes it has been posted, but all the topics have been closed
Sorta made my decision easy.



Lift is generated by the aircrafts wings, through the centre of pressure. Lift is only generated when there is a relative airflow going over the wings. This can be seen as the reason why some parked light aircraft 'take off' during hurricanes, even though the aircraft itself is not moving - the air is moving at a fast enough speed to generate the required lift for the aircraft to 'take off'

An aircraft on a treadmill would NOT have the required relative airflow, and WOULD NOT TAKE OFF. Simple.

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