MythBusters

[smack Down]

Originally posted by: rikadik
In order to understand how smack Down thinks I am actually contemplating drinking a gallon of methylated spirits and then running head first into a moving bus in an attempt to emulate his thought process.

So far the only viable hypotheses I can deduce from his postings are that:

1) Planes work much the same as cars, but fly because of the pilots' magical powers;
2) The greatest threat to human evolution and technological advancement is the risk of smack Down having any offspring;
3) There is no positive correlation between ATOT post count and intelligence; and/or
4) smack Down is a cat walking across the keyboard.

I'm seeing a lot more insults then formals or facts. Just show where the additional energy comes from for the plane to be different.

 

[Jeff7]

Originally posted by: Eeezee

Originally posted by: Jeff7
Really? Where is it debated? At least at subsonic speeds, I thought it was pretty well figured. Supersonic speeds, then things get a bit weird.

Link

Maybe the very basics of an airfoil are understood, but the exact understanding of the airflow on a very small level is the problem. Or if you want exact calculations, then you might have to factor in that oh-so-fun phenomenon: turbulence. Good old chaotic, inherently unpredictable, turbulence.


In any event, on a standard passenger jet or single-engine plane, it's the wing shape that produces lift when air flows over it. In a plane like a Cessna, yes, the propeller happens to push air over the wings, but not nearly enough to take off - otherwise, a Cessna would be a vertical-takeoff aircraft. It's the motion of the plane through the air, with sufficient speed, that lets the airfoil work its magic.

I believe that if the propeller were pushing enough air over the wings, it really could be a vertical-takeoff aircraft (massive/powerful propeller). What's the difference between the airplane moving through the air and air moving across the wings? There isn't any.

Just one little difference - an airplane moving through the air has a velocity component perpendicular to the direction of lift.
So a forward moving airplane is indeed a vertical takeoff machine, assuming your frame of reference is a point moving at the same forward speed as the aircraft. From that perspective, there is no difference.

 

[PurdueRy]

Originally posted by: smack Down

Originally posted by: rikadik
In order to understand how smack Down thinks I am actually contemplating drinking a gallon of methylated spirits and then running head first into a moving bus in an attempt to emulate his thought process.

So far the only viable hypotheses I can deduce from his postings are that:

1) Planes work much the same as cars, but fly because of the pilots' magical powers;
2) The greatest threat to human evolution and technological advancement is the risk of smack Down having any offspring;
3) There is no positive correlation between ATOT post count and intelligence; and/or
4) smack Down is a cat walking across the keyboard.

I'm seeing a lot more insults then formals or facts. Just show where the additional energy comes from for the plane to different.

The treadmill acts on the car's wheels which is attached to the drive train. Therefore, unless you keep the same speed as the treadmill in a car you will move backward in relation to the ground.

A plane is different. The wheels spin freely and therefore don't counteract the engines thrust....you want physics here it is.

Draw a free body diagram. We have a plane, wheels and the treadmill. The treadmill acts on the wheels causing them to spin...but that's about it. Sure there is some forces due to the rotating body but these are TINY. There is also a small friction force due to the bearings but this is also very small. Then there is a HUGE force forward placed on the BODY of the PLANE. Now balance forces and you quickly see that there is no counter to the engines force on the plane. Therefore the plane must move forward while it remains steady on the treadmill due to the treadmill only causing its wheels to spin.

Really the best example is back to roller skates. Put on a pair and get on a treadmill. Hold the frame of the treadmill and you will remain stationary. How much force does it take to hold yourself in place? The answer is the sum of the linear force, or in this case, the friction in the bearings and the tiny deflection of the wheel against the treadmill. Put easilly, very little.

Now increase the speed 20 fold. It still takes VERY LITTLE force from your hands to hold yourself in place. Why? Because again, the forces acting against the engines force are still VERY SMALL. This example perfectly reconstructs the aforementioned FBD. The force of your hands on the frame is equivalent to the force of the engines on the air. The force of the treadmill on your wheels is equivalent to the force of the treadmill on the planes wheels. As long as there is a net force then there must be ACCELERATION. ACCELERATION leads to take off.

If you cannot understand it from this then there is no hope for you.

 

[91TTZ]

The idiocy is immense in this thread. I can't believe that there are people on here posting about how aircraft work when they have no clue how they work.

 

[91TTZ]

Originally posted by: Jeff7

Originally posted by: sandorski
Well, the Air doesn't need to necessarily flow "over" the wings, kinda. If enough Air flows under the wings Lift can also be achieved, according to one theory anyway. There seems to be some disagreement as to which is more important, the Air flowing under the wings or the air flowing over the top of the wings. Generally speaking though, when one says "flow over the wings" they don't necessarily mean above. What they mean is "across the surface".

The more rapidly air flows, the lower its pressure. Look up "airfoil" - the top of the wing is curved, while the bottom is relatively flat. When the wing passes through air, the air on the bottom can pass straight across. But on the top, the air must flow over the curve - it needs to cross over more surface area, so it has to move faster. Result: higher pressure on the bottom than on top. Next result: Lift.
For air flowing only underneath the wings, the pressure under the wings would then be lower than that above, and so the higher pressure above would push down on the wings, keeping the plane firmly planted on the ground.


Welcome to Mythbusters...

You're talking about wings and ignore angle of attack. There are quite a few morons who think that wings needs to have the classic airfoil shape in order to produce lift. A wing could be perfectly flat and produce lift by by changing the angle of attack of that wing.

 

[rikadik]

Originally posted by: smack Down
I'm seeing a lot more insults then formals or facts. Just show where the additional energy comes from for the plane to be different.

I've read through your post in which I think you are trying show that if the plane does indeed move forward and the car remains stationary despite putting out the same amount of power (i.e. transferring same amount of energy) then the car somehow has less kinetic energy than the plane.

But this is obviously not a problem. It is circular logic. Saying the plane has some kinetic energy and the car does not (except moving parts in car and wheels) is no different to simply stating the plane will move forward and the car will not.

But maybe I just still don't understand quite where you're coming from.

Maybe you're wondering where the energy put out by the engine is going?

It's simply that the most of the plane's engines' energy is transferred to the air creating a net force on the body of the plane making it move forward.

However the car cannot transfer its engine's energy to the treadmill as the treadmill moves away as quickly as the wheels turn effectively providing no friction in order to create a net force on the body of the car.

I'm sure you'd agree treadmill spinning beneath a car's wheels at the right speed is no different to a car being suspended in mid-air. Not enough friction to move forwards. However surely you can see that a plane suspended in mid-air could move forwards?

And this is why the car and plane perform differently.

IN ANY CASE this is quite an odd way to explain it, I don't understand how you don't appreciate the explanation which usually make most people say "oh yeah I see, I get it now" as PurdueRy did above.

 

[smack Down]

I've read through your post in which I think you are trying show that if the plane does indeed move forward and the car remains stationary despite putting out the same amount of power (i.e. transferring same amount of energy) then the car somehow has less kinetic energy than the plane.

Ok doing good.

But this is obviously not a problem. It is circular logic. Saying the plane has some kinetic energy and the car does not (except moving parts in car and wheels) is no different to simply stating the plane will move forward and the car will not.

And here is where you make the mistake. It isn't a circular logic it is called a proof by contradiction. Either the theory of conservation of energy is wrong or that the plane behavies differently then the car is wrong because as you remember both had the same starting energy.

However the car cannot transfer its engine's energy to the treadmill as the treadmill moves away as quickly as the wheels turn effectively providing no friction in order to create a net force on the body of the car.

So where is the energy going in your theory? It can't just dissipate?

I'm sure you'd agree treadmill spinning beneath a car's wheels at the right speed is no different to a car being suspended in mid-air.

Sorry that isn't really true. It would only be true if the car was in a vacuum and there was no friction and engine was producing zero thrust. If the engine was producing power you would have to keep accelerating the treadmill to keep the car in place.

Not enough friction to move forwards. However surely you can see that a plane suspended in mid-air could move forwards?

IN ANY CASE this is quite an odd way to explain it, I don't understand how you don't appreciate the explanation which usually make most people say "oh yeah I see, I get it now" as PurdueRy did above.

Because it is wrong.

 

[Cerpin Taxt]

It would seem that in smackDown's universe, a sufficiently speedy car equipped with wings could take off and fly from LAX to John Wayne just like any ordinary aircraft. After all, if cars and planes are no different on a treadmill, they should also be the same on a still surface.

 

[PurdueRy]

Originally posted by: smack Down

I've read through your post in which I think you are trying show that if the plane does indeed move forward and the car remains stationary despite putting out the same amount of power (i.e. transferring same amount of energy) then the car somehow has less kinetic energy than the plane.

Ok doing good.

But this is obviously not a problem. It is circular logic. Saying the plane has some kinetic energy and the car does not (except moving parts in car and wheels) is no different to simply stating the plane will move forward and the car will not.

And here is where you make the mistake. It isn't a circular logic it is called a proof by contradiction. Either the theory of conservation of energy is wrong or that the plane behavies differently then the car is wrong because as you remember both had the same starting energy.

However the car cannot transfer its engine's energy to the treadmill as the treadmill moves away as quickly as the wheels turn effectively providing no friction in order to create a net force on the body of the car.

So where is the energy going in your theory? It can't just dissipate?

I'm sure you'd agree treadmill spinning beneath a car's wheels at the right speed is no different to a car being suspended in mid-air.

Sorry that isn't really true. It would only be true if the car was in a vacuum and there was no friction and engine was producing zero thrust. If the engine was producing power you would have to keep accelerating the treadmill to keep the car in place.

Not enough friction to move forwards. However surely you can see that a plane suspended in mid-air could move forwards?

IN ANY CASE this is quite an odd way to explain it, I don't understand how you don't appreciate the explanation which usually make most people say "oh yeah I see, I get it now" as PurdueRy did above.

Because it is wrong.

Hahaha. That's a good one. As you seem so fond of, point out the flaws so we can try to grasp where your logic is failing you. You like physics so you should be able to draw the FBD. That should explain everything to you. If you can't draw it, then don't bother posting more until you figure out how.

 

[randay]

i hope you guys realize that smack down just trolls the poat threads for his own enjoyment?

 

[smack Down]

Originally posted by: PurdueRy

Originally posted by: smack Down

I've read through your post in which I think you are trying show that if the plane does indeed move forward and the car remains stationary despite putting out the same amount of power (i.e. transferring same amount of energy) then the car somehow has less kinetic energy than the plane.

Ok doing good.

But this is obviously not a problem. It is circular logic. Saying the plane has some kinetic energy and the car does not (except moving parts in car and wheels) is no different to simply stating the plane will move forward and the car will not.

And here is where you make the mistake. It isn't a circular logic it is called a proof by contradiction. Either the theory of conservation of energy is wrong or that the plane behavies differently then the car is wrong because as you remember both had the same starting energy.

However the car cannot transfer its engine's energy to the treadmill as the treadmill moves away as quickly as the wheels turn effectively providing no friction in order to create a net force on the body of the car.

So where is the energy going in your theory? It can't just dissipate?

I'm sure you'd agree treadmill spinning beneath a car's wheels at the right speed is no different to a car being suspended in mid-air.

Sorry that isn't really true. It would only be true if the car was in a vacuum and there was no friction and engine was producing zero thrust. If the engine was producing power you would have to keep accelerating the treadmill to keep the car in place.

Not enough friction to move forwards. However surely you can see that a plane suspended in mid-air could move forwards?

IN ANY CASE this is quite an odd way to explain it, I don't understand how you don't appreciate the explanation which usually make most people say "oh yeah I see, I get it now" as PurdueRy did above.

Because it is wrong.

Hahaha. That's a good one. As you seem so fond of, point out the flaws so we can try to grasp where your logic is failing you. You like physics so you should be able to draw the FBD. That should explain everything to you. If you can't draw it, then don't bother posting more until you figure out how.

Sure.

Lets look at the wheels on the car. You say they are attached to the drive train right? the drive train is the transmission and engine. So when a the wheels on a car spin it turns the transimission which in turn turns the engine force the pistons up and down. Which part of that system makes it so the wheels can't spin?

 

[Jeff7]

Originally posted by: 91TTZ

Originally posted by: Jeff7

Originally posted by: sandorski
Well, the Air doesn't need to necessarily flow "over" the wings, kinda. If enough Air flows under the wings Lift can also be achieved, according to one theory anyway. There seems to be some disagreement as to which is more important, the Air flowing under the wings or the air flowing over the top of the wings. Generally speaking though, when one says "flow over the wings" they don't necessarily mean above. What they mean is "across the surface".

The more rapidly air flows, the lower its pressure. Look up "airfoil" - the top of the wing is curved, while the bottom is relatively flat. When the wing passes through air, the air on the bottom can pass straight across. But on the top, the air must flow over the curve - it needs to cross over more surface area, so it has to move faster. Result: higher pressure on the bottom than on top. Next result: Lift.
For air flowing only underneath the wings, the pressure under the wings would then be lower than that above, and so the higher pressure above would push down on the wings, keeping the plane firmly planted on the ground.


Welcome to Mythbusters...

You're talking about wings and ignore angle of attack. There are quite a few morons who think that wings needs to have the classic airfoil shape in order to produce lift. A wing could be perfectly flat and produce lift by by changing the angle of attack of that wing.

It seems to me though that even with an angle of attack change, it still produces a pressure differential, or at least some imbalance of forces which cases a net upward force.
In either case though, the wing must be moving forward relative to a fluid in order to get any kind of lift.

 

[PurdueRy]

Originally posted by: smack Down

Originally posted by: PurdueRy

Originally posted by: smack Down

I've read through your post in which I think you are trying show that if the plane does indeed move forward and the car remains stationary despite putting out the same amount of power (i.e. transferring same amount of energy) then the car somehow has less kinetic energy than the plane.

Ok doing good.

But this is obviously not a problem. It is circular logic. Saying the plane has some kinetic energy and the car does not (except moving parts in car and wheels) is no different to simply stating the plane will move forward and the car will not.

And here is where you make the mistake. It isn't a circular logic it is called a proof by contradiction. Either the theory of conservation of energy is wrong or that the plane behavies differently then the car is wrong because as you remember both had the same starting energy.

However the car cannot transfer its engine's energy to the treadmill as the treadmill moves away as quickly as the wheels turn effectively providing no friction in order to create a net force on the body of the car.

So where is the energy going in your theory? It can't just dissipate?

I'm sure you'd agree treadmill spinning beneath a car's wheels at the right speed is no different to a car being suspended in mid-air.

Sorry that isn't really true. It would only be true if the car was in a vacuum and there was no friction and engine was producing zero thrust. If the engine was producing power you would have to keep accelerating the treadmill to keep the car in place.

Not enough friction to move forwards. However surely you can see that a plane suspended in mid-air could move forwards?

IN ANY CASE this is quite an odd way to explain it, I don't understand how you don't appreciate the explanation which usually make most people say "oh yeah I see, I get it now" as PurdueRy did above.

Because it is wrong.

Hahaha. That's a good one. As you seem so fond of, point out the flaws so we can try to grasp where your logic is failing you. You like physics so you should be able to draw the FBD. That should explain everything to you. If you can't draw it, then don't bother posting more until you figure out how.

Sure.

Lets look at the wheels on the car. You say they are attached to the drive train right? the drive train is the transmission and engine. So when a the wheels on a car spin it turns the transimission which in turn turns the engine force the pistons up and down. Which part of that system makes it so the wheels can't spin?

The engine applies force via the wheels which must turn to propel the car forward. A Plane does not. That is all you need to know. If the treadmill is moving at 3m/s then the wheels must propel the car faster than 3m/s just to start providing any forward acceleration. This is vastly different than the plane scenario.

For a plane to keep up with a treadmill it doesn't need to travel at the same speed because it just has to counter the very small friction forces. For a car, it must travel at the exact same speed because that is where its force is being applied to.

As I said before, if you can't grasp my first example, you and your physics are a lost cause.

 

[CorCentral]

Let's make a pact and agree not to argue with the Numbnut anymore. Let him post his garbage. No one is that stupid to just keep on arguing. He's only wanting attention, that's all!
I'm sure when Mythbusters says "BUSTED" on this, he'll come up with a reason not to believe, something that was done wrong, etc.

Let's refrain from entertaining this nut and the others that think the plane will either not fly or crash.

 

[coldmeat]

Originally posted by: smack Down

Originally posted by: PurdueRy

Originally posted by: smack Down

I've read through your post in which I think you are trying show that if the plane does indeed move forward and the car remains stationary despite putting out the same amount of power (i.e. transferring same amount of energy) then the car somehow has less kinetic energy than the plane.

Ok doing good.

But this is obviously not a problem. It is circular logic. Saying the plane has some kinetic energy and the car does not (except moving parts in car and wheels) is no different to simply stating the plane will move forward and the car will not.

And here is where you make the mistake. It isn't a circular logic it is called a proof by contradiction. Either the theory of conservation of energy is wrong or that the plane behavies differently then the car is wrong because as you remember both had the same starting energy.

However the car cannot transfer its engine's energy to the treadmill as the treadmill moves away as quickly as the wheels turn effectively providing no friction in order to create a net force on the body of the car.

So where is the energy going in your theory? It can't just dissipate?

I'm sure you'd agree treadmill spinning beneath a car's wheels at the right speed is no different to a car being suspended in mid-air.

Sorry that isn't really true. It would only be true if the car was in a vacuum and there was no friction and engine was producing zero thrust. If the engine was producing power you would have to keep accelerating the treadmill to keep the car in place.

Not enough friction to move forwards. However surely you can see that a plane suspended in mid-air could move forwards?

IN ANY CASE this is quite an odd way to explain it, I don't understand how you don't appreciate the explanation which usually make most people say "oh yeah I see, I get it now" as PurdueRy did above.

Because it is wrong.

Hahaha. That's a good one. As you seem so fond of, point out the flaws so we can try to grasp where your logic is failing you. You like physics so you should be able to draw the FBD. That should explain everything to you. If you can't draw it, then don't bother posting more until you figure out how.

Sure.

Lets look at the wheels on the car. You say they are attached to the drive train right? the drive train is the transmission and engine. So when a the wheels on a car spin it turns the transimission which in turn turns the engine force the pistons up and down. Which part of that system makes it so the wheels can't spin?

I tried to not post in this thread, but I just had to quote this. You say that the wheels on a car drive the engine? Then how does it move from a dead stop? If you can't understand that, then how are we supposed to believe anything you say about how a plane works?

 

[ShockwaveVT]

mods, whatever happened to issuing vacations to blatant trolls like smack Down?

p.s. I'm curious to see if the mythbusters use a full-size plane (like a Cessna) or if they utilize a model airplane.

 

[coldmeat]

Originally posted by: ShockwaveVT
mods, whatever happened to issuing vacations to blatant trolls like smack Down?

p.s. I'm curious to see if the mythbusters use a full-size plane (like a Cessna) or if they utilize a model airplane.

Here's a preview

 

[CorCentral]

Originally posted by: coldmeat

Originally posted by: ShockwaveVT
mods, whatever happened to issuing vacations to blatant trolls like smack Down?

p.s. I'm curious to see if the mythbusters use a full-size plane (like a Cessna) or if they utilize a model airplane.

Here's a preview

Even the Pilot think he's not going to take off. What an idiot.
I'm going to BOLD this and make it known.


MODS........ I BEG you to Ban me for 1mth from ANANDTECH if I'm wrong on this!
I'm saying the plane will fly!
Let's see if other Members have the Balls to step forward for a 1 mth Ban if they are wrong. Remember, you are asking to be banned if your are wrong!!!!

Who do I have with me on this? :camera: ....... If you're not sure, then don't commit! :laugh:

 

[Pacfanweb]

Any idiot knows the plane isn't going to take off. Why is this even considered a myth? They'd be better served looking for the Loch Ness Monster.

 

[CorCentral]

Originally posted by: Pacfanweb
Any idiot knows the plane isn't going to take off. Why is this even considered a myth? They'd be better served looking for the Loch Ness Monster.

Care to bet a 1 mth Suspension from the forum on your thought? (See my post above)
I really doubt you will!

Hell, if you lose, we'll get rid of half the idiots in this thread for 1 whole MTH! You do know you're going to lose, right?!?

I'm saying the Plane WILL Fly!


EDIT: Look at my other thread on betting if the plane will take off or not!

 

[PurdueRy]

Originally posted by: CorCentral

Originally posted by: Pacfanweb
Any idiot knows the plane isn't going to take off. Why is this even considered a myth? They'd be better served looking for the Loch Ness Monster.

Care to bet a 1 mth Suspension from the forum on your thought? (See my post above)
I really doubt you will!

Hell, if you lose, we'll get rid of half the idiots in this thread for 1 whole MTH! You do know you're going to lose, right?!?

I'm saying the Plane WILL Fly!


EDIT: Look at my other thread on betting if the plane will take off or not!

I'm with you...obviously.

 

[biggestmuff]

I'm at work right now with youtube blocked. Before I make a decision on the episode in the other thread, will someone tell me, how long is the treadmill runway in the Mythbusters' setup?

 

[Cold Steel]

Originally posted by: biggestmuff
I'm at work right now with youtube blocked. Before I make a decision on the episode in the other thread, will someone tell me, how long is the treadmill runway in the Mythbusters' setup?

Apparently, they do not use an actual treadmill/conveyor belt. They have a tarp 2000 feet long sitting flat on the runway and drag it with a truck under the plane.

I have no doubt that Mythbusters will screw this up just like they screw up so many other things. The pilot of the plane thinks it won't take off, but I'll bet anything all he tries to do is stay in place on the tarp without applying enough power to move the plane forward.

Oh, yeah. And then they blow the plane up.

 

[biggestmuff]

Originally posted by: Cold Steel

Originally posted by: biggestmuff
I'm at work right now with youtube blocked. Before I make a decision on the episode in the other thread, will someone tell me, how long is the treadmill runway in the Mythbusters' setup?

Apparently, they do not use an actual treadmill/conveyor belt. They have a tarp 2000 feet long sitting flat on the runway and drag it with a truck under the plane.

I have no doubt that Mythbusters will screw this up just like they screw up so many other things. The pilot of the plane thinks it won't take off, but I'll bet anything all he tries to do is stay in place on the tarp without applying enough power to move the plane forward.

Oh, yeah. And then they blow the plane up.

Okay. In my mind that could work as a good test, but who knows.

I think CorCentral should change the question in his thread. He shouldn't be asking whether the plane will fly or crash, but how the Mythbusters will rank the myth; busted, plausible or fact. Even then anything could happen in that episode.

Do we know what airplane they're using?

 

[rikadik]

Originally posted by: smack Down

So where is the energy going in your theory? It can't just dissipate?

The energy is making the wheels spin. That's where the energy is going. It's really not difficult to understand. But the wheels cannot use their energy to create a forward force on the car as there is essentially no friction with the treadmill! There is no lost energy - the car's kinetic energy is just in the wheels spinning faster and faster.

A plane however converts most of its energy into air rushing out of the engines causing a forward force on the plane.

But if you're such a physics genius (and not just a trolling retard like most suggest) then why don't YOU explain where the energy produced by the engines is going in the plane situation if you claim it sits still?