160 replies to this topic

[[V1]-[VR]-[V2]]

Pavehawk, on Nov 30 2005, 05:37 PM, said:

But when the plane is moving there is no signifcent force on the plane from the conveyor belt...  so your representation of a negative force if false.

if it is false then there would be one force going that way -> and the plane would move into that direction. don't deny there is no force going that way -> or ull have to shut off the engine

Edited by [V1]-[VR]-[V2], 30 November 2005 - 11:45 AM.

[wnfaknd]

[V1]-[VR]-[V2], on Nov 30 2005, 08:33 AM, said:

well i might have done things wrong but

the plane won't move so there won't be any wind speed so there will be no lift

Obviously you are not reading...
The plane will move when the propeller start spinning.

Name one thing that would keep the airplane from moving forward, even if the treadmill is moving backwards 100 times faster than the airplane is moving foward,  the airplane would still take off (assumiming that the wheels can take the extra spining).

The treadmill is independant of any airplane movement because the wheels spin freely.  No matter what the treadmil is doing, moving foward, moving backwards, staying still... whatever, it will not impact the airplane from moving forward, getting air over the wings and  eventually take off.  In fact, it will take about the same distance to take off no matter what the treadmil is doing.

[[V1]-[VR]-[V2]]

wnfaknd, on Nov 30 2005, 05:40 PM, said:

[V1 said:

-[VR]-[V2],Nov 30 2005, 08:33 AM] well i might have done things wrong but

the plane won't move so there won't be any wind speed so there will be no lift

Obviously you are not reading...
The plane will move when the propeller start spinning.

Name one thing that would keep the airplane from moving forward, even if the treadmill is moving backwards 100 times faster than the airplane is moving foward,  the airplane would still take off (assumiming that the wheels can take the extra spining).

The treadmill is independant of any airplane movement because the wheels spin freely.  No matter what the treadmil is doing, moving foward, moving backwards, staying still... whatever, it will not impact the airplane from moving forward, getting air over the wings and  eventually take off.  In fact, it will take about the same distance to take off no matter what the treadmil is doing.

there also is gravity and becuz of that the plane WILL go backwards when the belt is going faster then the plane

Edited by [V1]-[VR]-[V2], 30 November 2005 - 11:45 AM.

[Pavehawk]

[V1 said:

-[VR]-[V2],Nov 30 2005, 11:33 AM] well i might have done things wrong but

the plane won't move so there won't be any wind speed so there will be no lift

Why won't the plane move?  The only way the plane wouldnt move if the power was adjusted to be the forward force of the backwards friction force.  In otherwards, the force pulling the plane backwards due to friction on the wheels is very miniscule compared to the powergoing forward from that 150hp engine and propellor.

Maybe this will make more sense:

You are in your car on the ice rink in Madison Square Garden.  You hit the breaks and you hit the gas, will the car move?  Not really because the engine turns the transmission which turns the wheels, if the wheels are LOCKED the car will not move.

Now, you are in your little 152 on the ice.   You put the parking break on and u apply full power, will the plane move?  YES!  Are the wheels moving?  Not at all....  They are just SLIDING over the ice, just as in this case, the conveyor belt is sliding backwards under the wheels, or the wheels are sliding over the conveyor belt.

Edited by Pavehawk, 30 November 2005 - 11:44 AM.

[[V1]-[VR]-[V2]]

Pavehawk, on Nov 30 2005, 05:44 PM, said:

[V1 said:

-[VR]-[V2],Nov 30 2005, 11:33 AM] well i might have done things wrong but

the plane won't move so there won't be any wind speed so there will be no lift

Why won't the plane move?  The only way the plane wouldnt move if the power was adjusted to be the forward force of the backwards friction force.  In otherwards, the force pulling the plane backwards due to friction on the wheels is very miniscule compared to the powergoing forward from that 150hp engine and propellor.

Maybe this will make more sense:

You are in your car on the ice rink in Madison Square Garden.  You hit the breaks and you hit the gas, will the car move?  Not really because the engine turns the transmission which turns the wheels, if the wheels are LOCKED the car will not move.

Now, you are in your little 152 on the ice.   You put the parking break on and u apply full power, will the plane move?  YES!  Are the wheels moving?  Not at all....  They are just SLIDING over the ice, just as in this case, the conveyor belt is sliding backwards under the wheels, or the wheels are sliding over the conveyor belt.

wasnt the belt going as fast as the plane? counterwise?

[Pavehawk]

[V1]-[VR]-[V2], on Nov 30 2005, 11:39 AM, said:

Pavehawk, on Nov 30 2005, 05:37 PM, said:

But when the plane is moving there is no signifcent force on the plane from the conveyor belt...  so your representation of a negative force if false.

if it is false then there would be one force going that way -> and the plane would move into that direction. don't deny there is no force going that way -> or ull have to shut off the engine

You said they were EQUAL, they are obviously not equal when the plane is moving forward, not stationary.  If it was stationary then yes the plane will move backwards because there is no forward force to overcome the fricton of the belt on the wheels.

[Pavehawk]

Yes, it is moving in the opposite direction but the forces are not equal.

The plane is generating power to go forward, correct?  What force is pulling the plane back beisdes drag?  The FRICTION between the wheels and the belt itself.  Are you going to stand there and say that the thrust to pull a plane to takeoff speed is going to be EQUAL to that FRICTION of the belt on the wheels???

[[V1]-[VR]-[V2]]

Pavehawk, on Nov 30 2005, 05:48 PM, said:

[V1 said:

-[VR]-[V2],Nov 30 2005, 11:39 AM]

Pavehawk, on Nov 30 2005, 05:37 PM, said:

But when the plane is moving there is no signifcent force on the plane from the conveyor belt...  so your representation of a negative force if false.

if it is false then there would be one force going that way -> and the plane would move into that direction. don't deny there is no force going that way -> or ull have to shut off the engine

You said they were EQUAL, they are obviously not equal when the plane is moving forward, not stationary.  If it was stationary then yes the plane will move backwards because there is no forward force to overcome the fricton of the belt on the wheels.

i didn't say it was friction

[Pavehawk]

[V1]-[VR]-[V2], on Nov 30 2005, 11:54 AM, said:

Pavehawk, on Nov 30 2005, 05:48 PM, said:

[V1 said:

-[VR]-[V2],Nov 30 2005, 11:39 AM]

Pavehawk, on Nov 30 2005, 05:37 PM, said:

But when the plane is moving there is no signifcent force on the plane from the conveyor belt...  so your representation of a negative force if false.

if it is false then there would be one force going that way -> and the plane would move into that direction. don't deny there is no force going that way -> or ull have to shut off the engine

You said they were EQUAL, they are obviously not equal when the plane is moving forward, not stationary.  If it was stationary then yes the plane will move backwards because there is no forward force to overcome the fricton of the belt on the wheels.

i didn't say it was friction

then what is it?

[[V1]-[VR]-[V2]]

Pavehawk, on Nov 30 2005, 05:55 PM, said:

[V1 said:

-[VR]-[V2],Nov 30 2005, 11:54 AM]

Pavehawk, on Nov 30 2005, 05:48 PM, said:

[V1 said:

-[VR]-[V2],Nov 30 2005, 11:39 AM]

Pavehawk, on Nov 30 2005, 05:37 PM, said:

But when the plane is moving there is no signifcent force on the plane from the conveyor belt...  so your representation of a negative force if false.

if it is false then there would be one force going that way -> and the plane would move into that direction. don't deny there is no force going that way -> or ull have to shut off the engine

You said they were EQUAL, they are obviously not equal when the plane is moving forward, not stationary.  If it was stationary then yes the plane will move backwards because there is no forward force to overcome the fricton of the belt on the wheels.

i didn't say it was friction

then what is it?

the force that makes the belt move

btw u saying the plane will move?

Edited by [V1]-[VR]-[V2], 30 November 2005 - 11:59 AM.

[wnfaknd]

V1 VR V2.
Lets say you put a might 747 on top of conveyor belt and the belt is not moving.  Everything is standing still.  Lets  assume this 747 has the best wheels ever created by man and the gears are super lubricated and the friction is negligible.  
Now lets turn on the conveyor belt so it goes backwards.  Do you think the 747 will move backwards too? or do you think the 747 will stand still?

Well, the answer is, it will stand still.  The airplane will not move.  The wheels will spin, but the airplane will ramain stationary.  Now lets crank up that conveyor belt and make it go 100 miles per hour.  Do you think that 747 will  move backwards?  No, it will not.  It will remain on the same place.  Now turn on the engines on the 747 and push the throttle to maximum, do you think it will move forward?  Yes, it will. Because the engines are pushing backwards on the air, not the conveyor belt.  Now, let crank up that belt even more and make it go backwards 500 miles per hour, do you think the airplane will all of a sudden start moving backwards?  No, it will keep moving forward, because the wheels spin freely.

[Pavehawk]

[V1]-[VR]-[V2], on Nov 30 2005, 11:57 AM, said:

Pavehawk, on Nov 30 2005, 05:55 PM, said:

[V1 said:

-[VR]-[V2],Nov 30 2005, 11:54 AM]

Pavehawk, on Nov 30 2005, 05:48 PM, said:

[V1 said:

-[VR]-[V2],Nov 30 2005, 11:39 AM]

Pavehawk, on Nov 30 2005, 05:37 PM, said:

But when the plane is moving there is no signifcent force on the plane from the conveyor belt...  so your representation of a negative force if false.

if it is false then there would be one force going that way -> and the plane would move into that direction. don't deny there is no force going that way -> or ull have to shut off the engine

You said they were EQUAL, they are obviously not equal when the plane is moving forward, not stationary.  If it was stationary then yes the plane will move backwards because there is no forward force to overcome the fricton of the belt on the wheels.

i didn't say it was friction

then what is it?

the force that makes the belt move

btw u saying the plane will move?

lol, okay lets make the belt out of really slippery ice, and u place a box on it.  If you make that belt move fast enough, the box will not move because there isnt enough FRICTION to PULL the box backwards, make sense?

[[V1]-[VR]-[V2]]

ive always said the plane wouldnt move wth and your proving me that?

[Corsair1138]

[V1]-[VR]-[V2],

You are obviously not reading what we typing here, because if you did, you'd understand that the two forces are independet.

Here's my post from before. READ IT and UNDERSTAND IT. Post your questions you have of this example. If you can't understand this, then you will NEVER be able understand why the plane flies. So, read this again and tell me if you understand it:



Take a walking treadmill, like the ones in the airport (long, flat, treadmill).

Put on rollerblades.

Now, if you stand on the treadmill and the treadmill starts moving, it will push you backwards. This is because there are no forces acting on you to propel yourself forward. The wheels of the rollerblades are not moving.

Now take a rope and tie it to the far end of this treadmill and hold onto the rope. As the treadmill starts moving at 1mph backwards, what happens? You stand still in relation to the ground around the treadmill. In relation to the treadmill you are moving at 1mph and the wheels are spinning!! The difference here is that now you have a force pulling on you, that is the force of you holding the rope.

Now what would happen if you started to PULL yourself forward with the rope? Would you move?

Yes, you would start moving forward. Pretty obvious huh? Lets say the treadmill is moving backwards at 1mph and you pulling yourself forward at 1mph in relation to the ground around the treadmill. Well, in relation to the treadmill you will be going 2mph, hence why the wheels would turn at 2mph.

Edited by Corsair1138, 30 November 2005 - 12:04 PM.

[Prancer]

Can we maybe just assume the plane in question is a Harrier and the answer would be yes?

[wnfaknd]

[V1]-[VR]-[V2], on Nov 30 2005, 09:02 AM, said:

ive always said the plane wouldnt move wth and your proving me that?

Let's see if you can grasp this one.

Get your skateboard and put it on top of the carpet.  If you pull the carpet backwards, the skateboard will pretty much stay still.  The wheels will move, but the skateboard will remain in about the same place.

Its the same thing with the place, the conveyor belt, will not affect the movement of the airplane because the wheels spin freely.  If you add a propeller to your skateboard and turn  it on, the skate board will move forward no matter how hard you pull on the carpet.

[Pavehawk]

Corsair1138, on Nov 30 2005, 12:03 PM, said:

[V1]-[VR]-[V2],

You are obviously not reading what we typing here, because if you did, you'd understand that the two forces are independet.

Here's my post from before. READ IT and UNDERSTAND IT. Post your questions you have of this example. If you can't understand this, then you will NEVER be able understand why the plane flies. So, read this again and tell me if you understand it:



Take a walking treadmill, like the ones in the airport (long, flat, treadmill).

Put on rollerblades.

Now, if you stand on the treadmill and the treadmill starts moving, it will push you backwards. This is because there are no forces acting on you to propel yourself forward. The wheels of the rollerblades are not moving.

Now take a rope and tie it to the far end of this treadmill and hold onto the rope. As the treadmill starts moving at 1mph backwards, what happens? You stand still in relation to the ground around the treadmill. In relation to the treadmill you are moving at 1mph and the wheels are spinning!! The difference here is that now you have a force pulling on you, that is the force of you holding the rope.

Now what would happen if you started to PULL yourself forward with the rope? Would you move?

Yes, you would start moving forward. Pretty obvious huh? Lets say the treadmill is moving backwards at 1mph and you pulling yourself forward at 1mph in relation to the ground around the treadmill. Well, in relation to the treadmill you will be going 2mph, hence why the wheels would turn at 2mph.

im trying to explain its and bits of the BIG picture.  The force are not independent.  No matter where you go, there will be friction.  If you took the same plane and took off from a runway it will take off sooner (Not by much) then if it were on the conveyor belt because there is SOME force pulling the plane backwards, not much, but SOME.  I never said the plane wouldnt take off, of course it will.  I was not talking to you guys, I was talking to Floris trying to prove that the BACKWARDS FORCE DOES NOT EQUAL THE FORWARD FORCE on his DRAWING not on what others said.  

[[V1]-[VR]-[V2]]

wnfaknd, on Nov 30 2005, 06:05 PM, said:

[V1 said:

-[VR]-[V2],Nov 30 2005, 09:02 AM] ive always said the plane wouldnt move wth and your proving me that?

Let's see if you can grasp this one.

Get your skateboard and put it on top of the carpet.  If you pull the carpet backwards, the skateboard will pretty much stay still.  The wheels will move, but the skateboard will remain in about the same place.

Its the same thing with the place, the conveyor belt, will not affect the movement of the airplane because the wheels spin freely.  If you add a propeller to your skateboard and turn  it on, the skate board will move forward no matter how hard you pull on the carpet.

well if i won't move in the plane and there is a thrust force

THERE MUST BE A FORCE BACKWARDS

because

newtons law: when forces are equal the object will move with a constant speed or it won't move. im sorry but am i understanding this law wrong?

[Pavehawk]

wnfaknd, on Nov 30 2005, 12:05 PM, said:

[V1 said:

-[VR]-[V2],Nov 30 2005, 09:02 AM] ive always said the plane wouldnt move wth and your proving me that?

Let's see if you can grasp this one.

Get your skateboard and put it on top of the carpet.  If you pull the carpet backwards, the skateboard will pretty much stay still.  The wheels will move, but the skateboard will remain in about the same place.

Its the same thing with the place, the conveyor belt, will not affect the movement of the airplane because the wheels spin freely.  If you add a propeller to your skateboard and turn  it on, the skate board will move forward no matter how hard you pull on the carpet.

BUT if you pull it slow enough the skateboard will move backwards due to friction.  Hopefully this will explain what I was trying to get at.

[Corsair1138]

Pavehawk, on Nov 30 2005, 12:06 PM, said:

im trying to explain its and bits of the BIG picture.  The force are not independent.  No matter where you go, there will be friction.  If you took the same plane and took off from a runway it will take off sooner (Not by much) then if it were on the conveyor belt because there is SOME force pulling the plane backwards, not much, but SOME.  I never said the plane wouldnt take off, of course it will.  I was not talking to you guys, I was talking to Floris trying to prove that the BACKWARDS FORCE DOES NOT EQUAL THE FORWARD FORCE on his DRAWING not on what others said.  

Pavehawk, that post was for V1-VR-V2, not you. (I originally had your name at top but corrected that).

Yes, we know about friction. But friction is so minimal in this case that it doesn't come into play. Like we agreed to earlier, the runway will be lengthen by some measured amount. For this discussion, friction can be ignored to some extent.