conveyor belt and plane answered at last ??

[Deleted member 63160]

The version of the question I first read stated that the treadmill operator "tried" to match the planes wheel speed. The version the "non flyers" subscribe to is basically along the lines of " what happens when a plane that isn't allowed to take off tries to take off, should take off but doesn't". I reckon the non flyers modified question was designed by people who initially forgot that a planes wheels aren't powered.

 

[Trazor]

For all those, it won't take off merchants, consider this.......

According to you lot an aeroplane coming into LAND on this conveyor belt would have to stop INSTANTLY the moment it touched down, as you believe the conveyor stops forward movement.

Thats 400 metric tonnes stopped instantly( boeing 747 )

This is obvious nonsense.

Not instantly but eventually yes, remember the 747 has forward momentum , the wheels currently stationary, when it touches down on the conveyor, which is travelling backwards the wheels will spin forward at 100mph + whatever the touchdown speed of said plane was

When the forward momentum clearly slows and the wheel speed matches the conveyor speed the 747 will stand still, if it slows then it'll go backwards

The conveyor MATCHES the wheel speed.

Wheel speed is only generated when the plane moves FORWARD.

Therefore the conveyor can ONLY MOVE when the plane is moving forward.

You cannot have the plane standing still on a conveyor doing 100 mph, because if the plane is standing still it generates no wheel speed for the conveyor to react to.

 

[crank39]

For all those, it won't take off merchants, consider this.......

According to you lot an aeroplane coming into LAND on this conveyor belt would have to stop INSTANTLY the moment it touched down, as you believe the conveyor stops forward movement.

Thats 400 metric tonnes stopped instantly( boeing 747 )

This is obvious nonsense.

Not instantly but eventually yes, remember the 747 has forward momentum , the wheels currently stationary, when it touches down on the conveyor, which is travelling backwards the wheels will spin forward at 100mph + whatever the touchdown speed of said plane was

When the forward momentum clearly slows and the wheel speed matches the conveyor speed the 747 will stand still, if it slows then it'll go backwards

The conveyor MATCHES the wheel speed.

Wheel speed is only generated when the plane moves FORWARD.

Therefore the conveyor can ONLY MOVE when the plane is moving forward.

You cannot have the plane standing still on a conveyor doing 100 mph, because if the plane is standing still it generates no wheel speed for the conveyor to react to.

Chicken and egg question then innit

 

[crank39]

crank39 wrote

Belt going backwards at 100mph must mean wheels turn forward at 100mph.........AGREED?

Nope.

How does a wheel "turn" forward at 100mph?

D'errr, conveyor travels one way means wheels turn the opposite way, but we've gone past this point, does this not happen on your planet?

Nope.
That doesn't answer the question. Only adds confusion as you've mentioned a "conveyor" which has nothing to do with the question I was asking.

So once again ..how does a wheel "turn" forward" at 100mph? Just answer the question. (he won't)

Define what exactly is "turning" and what exactly is moving "forward" from your statement above.

Been answered many times, put a stationary wheel on a conveyor and it will spin in the opposite direction to said conveyor but not necessarily move forward, forward movement comes when thrust is applied

 

[Deleted member 63160]

Chicken and egg question then innit

That's a different response are you seeing it now?

 

[crank39]

Chicken and egg question then innit

That's a different response are you seeing it now?

The question was posted earlier for all to read and to familiarise yourselves with the parameters and constraints of the question, it said nothing about a 747 coming in to land

The question is there and has been answered

 

[Deleted member 63160]

The question is there and has been answered

Cool. Do you know where the question is that you refer to as I may not have read that version. Ta muchly if you can.

 

[Trazor]

The question was posted earlier for all to read and to familiarise yourselves with the parameters and constraints of the question, it said nothing about a 747 coming in to land

The question is there and has been answered

The 747 was only mentioned because of its size, the plane will take off irrespective of its size..Thanks to Newtons 3rd law of motion, which is immutable.

 

[Norcon]

crank39 wrote

Belt going backwards at 100mph must mean wheels turn forward at 100mph.........AGREED?

Nope.

How does a wheel "turn" forward at 100mph?

D'errr, conveyor travels one way means wheels turn the opposite way, but we've gone past this point, does this not happen on your planet?

Nope.
That doesn't answer the question. Only adds confusion as you've mentioned a "conveyor" which has nothing to do with the question I was asking.

So once again ..how does a wheel "turn" forward" at 100mph? Just answer the question. (he won't)

Define what exactly is "turning" and what exactly is moving "forward" from your statement above.

Been answered many times, put a stationary wheel on a conveyor and it will spin in the opposite direction to said conveyor but not necessarily move forward, forward movement comes when thrust is applied

How does a wheel "turn" forward at 100 mph?
Can you answer the question? Yes or no?

 

[doitall]

The plane is stood on the conveyor belt, there's no contact with the ground as in that silly video. and nothing is moving.

As the belt picks up speed the plane must increase the engine speed to stop it going backward, in the meantime the belt is turning the wheels at the same speed.

We now have a stalemate, the conveyor is trying to take the plane backward, and the propeller is trying to move the plane forward, we have equilibrium.

Plane still ain't taking off

 

[crank39]

crank39 wrote

Belt going backwards at 100mph must mean wheels turn forward at 100mph.........AGREED?

Nope.

How does a wheel "turn" forward at 100mph?

D'errr, conveyor travels one way means wheels turn the opposite way, but we've gone past this point, does this not happen on your planet?

Nope.
That doesn't answer the question. Only adds confusion as you've mentioned a "conveyor" which has nothing to do with the question I was asking.

So once again ..how does a wheel "turn" forward" at 100mph? Just answer the question. (he won't)

Define what exactly is "turning" and what exactly is moving "forward" from your statement above.

Been answered many times, put a stationary wheel on a conveyor and it will spin in the opposite direction to said conveyor but not necessarily move forward, forward movement comes when thrust is applied

How does a wheel "turn" forward at 100 mph?
Can you answer the question? Yes or no?

I've answered it, not sure i can think of any more ways of explaining it, wheel turns forward when ground moves backwards........owzat?

 

[Norcon]

crank39 wrote

Belt going backwards at 100mph must mean wheels turn forward at 100mph.........AGREED?

Nope.

How does a wheel "turn" forward at 100mph?

D'errr, conveyor travels one way means wheels turn the opposite way, but we've gone past this point, does this not happen on your planet?

Nope.
That doesn't answer the question. Only adds confusion as you've mentioned a "conveyor" which has nothing to do with the question I was asking.

So once again ..how does a wheel "turn" forward" at 100mph? Just answer the question. (he won't)

Define what exactly is "turning" and what exactly is moving "forward" from your statement above.

Been answered many times, put a stationary wheel on a conveyor and it will spin in the opposite direction to said conveyor but not necessarily move forward, forward movement comes when thrust is applied

How does a wheel "turn" forward at 100 mph?
Can you answer the question? Yes or no?

I've answered it, not sure i can think of any more ways of explaining it, wheel turns forward when ground moves backwards........owzat?

I'll take that as a NO then. If you can't even explain the difference between rpm and mph then its pointless reading any of your posts on this subject. Over and out.

 

[Trazor]

We now have a stalemate, the conveyor is trying to take the plane backward, and the propeller is trying to move the plane forward, we have equilibrium.

The conveyor MATCHES the wheel speed.

Wheel speed is only generated when the plane moves FORWARD.

Therefore the conveyor can ONLY MOVE when the plane is moving forward.

You cannot have the plane standing still on a conveyor doing 100 mph, because if the plane is standing still it generates no wheel speed for the conveyor to react to.

 

[crank39]

Bye then

 

[matt1e]

which bit of my post is confusing you?

All of it really :

Belt going backwards at 100mph must mean wheels turn forward at 100mph.........AGREED?

Nope

If you agree with the above then you MUST agree that the plane is currently stationary................AGREED?

I don't so nope

For the plane to move forward up the conveyor and hopefully to take of speed it needs to increase thrust..............AGREED?

Yes

No one is disputing that the plane has plenty of thrust in reserve to overcome the conveyor going backwards

No dispute here, the question ends with " the pilot starts to apply thrust", however you still seem to think that the wheel RPM has any bearing on it

BUT here's the clincher, in order for the plane to move forward up the conveyor the wheels will need to travel faster than they already are, remember they are already travelling at 100 mph because the conveyor is too.....................PLEASE SAY YOU AGREE

Sorry to disappoint but nope

As soon as the plane moves forward, which it could easily do with extra thrust the wheels are NO LONGER travelling at the same speed as the conveyor and that is not within the parameters of the question, if the wheel speed is equal to the conveyor then the plane will stand still and will not take off because of no air flow over the wing surfaces

The conveyor speed can match the wheel speed ie the wheel RPM
it doesn't matter one jot,
Which of these do you agree with
the wheel turns because the plane is moving forward
The plane moves forward because the wheel turns

Put it like this in the confines of the question posted
Because the wheels arevturning that means that the plane must be going forward AGREED?
It has to be the plane going forward because the belt speed is linked to the wheels by sensors AGREED?
So if the speed off the wheels speed up then that must be because the plane is speeding up , therefore it must have more forward momentum AGREED?
What happens when the plane has enough forward momentum?
The conveyor will stop because the wheels will not be spinning anymore and they'll be nicely tucked away thank you

Please say you agree