Principles of flight?

[RedMist]

I'll repeat this again and again and again until someone who ansered "no" answers the questions.

What groundspeed is the plane doing at take off?
What wheelspeed is the plane doing at takeoff?
What speed is the conveyor doing (without rewording the original quesiton, ie it matches the wheelspeed in an opposite direction.)?
What groundspeed is the plane doing?


I dont give a shit about thrust or how you power the plane. You can't manipulate the question, please re-read it for clarification. Its on page 1.

If you want to move forward an inch... does the wheels move?
if the wheels move, does the conveyor move?

[RedMist]

So what I'm trying to say is:

The speed of the conveyer will be double but in opposite direction of the plane or will be same as plane's and in same direction deppends how the conditions are interpreted.

Sergei, your saying that the the wheelspeed is double that of the conveyor speed? Please re-read the first post.

If the convyor is doing 301kph and the wheelspeed is 300kph IE the groundspeed is 1kph does it meet the following criteria "The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation. "

Forget thrust, forget friction, just attempt to propose an answer that meets the first question. As without wheelslip yours doesnt.

[RedMist]

basically if you look at it carefully and think about it
the wheel will not rotate at all

this is the funtion of the converyer
so the plane will take off
the wheels would not rotate
and the convayer would match the planes groundspeed

v

So if the wheels don't rotate, the wheels skid? A braked plane can accelerate to a takeoff with the wheels locked?
Not trying to oppose you here, but 0 wheelspeed = 0 conveyor speed. Which only leaves the option of wheels sliding. So can a plane take off with wheels locked?

[vvega]

its hard to explain my way of seeing it
the wheels woulnt be locked as teh plane moves forward the conveyer would match there speed causing them to not spin but to move forwarn (the function of the travelator)

so the travelater would not allow the wheels to attually turn but in doing that the travelator would match the forward motion of the plane

i might tri to make a animation later to explain it

cheers redmist

v

[sergei]

I competely agree to vvega, here is another question, is there anything forbidding for wheels not to rotate? Have you seen unicycles (cycle with only one wheel) and how people can stand still (almost) on them without falling off? same way the conveyer could act to compensate for rotation of the wheels on the plane... Hey I even remember writing a small C program for my AI paper a few years back (using fuzzy logic) to balance a tall pivoted (on its base) load on a cart... this sort of code can be utilized to simulate the problem with the plane.

As I said above the description of the conveyor is flawed in the question..
as there are not statet some figures about thrust , friction coeficient, efficiency of the bearings, how much can conveyor out power, thrust created by plane, air density, mass of the plane, gravity, and so on, we can assume that power of the conveyor is limited, there is some friction between wheels/belt, the plane can fly, there is enough thrust to get plane moving to lift off speed, etc. hence I assume that plane will lift off.

THINK OF THE CONVEYER AS SECOND SET OF WHEELS!

Imagine another situation, the plane is actually on a trolley with brakes on, while trolley is on the flat ground, will the plane lift off, hey it has got the brakes on?

[UZZ30]

Jezz, this post has been so popular. nearly 3000 views!

Great topic however...

[sergei]

Also there is nothing preventing the conveyor to acclerate from its initial 0 state...

Think about a trolley on the wheels, initially it is at rest, if you try to push it it will move, why would it move - becuase it is relativile solid object and most of your energy (push) will transform into trolley kinetic energy. The initial rest state of the trolley does not prevent it from moving, otherwise the energy conservation law would go in the bin... (if trolley would not move for some reason the friction force or some other cause would transform your energy not in kinetic but into heat, another form of energy).

For same reason inital rest state of the conveyor belt does not prevent it from moving when thrust of the plane is applied.

[RedMist]

Also there is nothing preventing the conveyor to acclerate from its initial 0 state...

Think about a trolley on the wheels, initially it is at rest, if you try to push it it will move, why would it move - becuase it is relativile solid object and most of your energy (push) will transform into trolley kinetic energy. The initial rest state of the trolley does not prevent it from moving, otherwise the energy conservation law would go in the bin... (if trolley would not move for some reason the friction force or some other cause would transform your energy not in kinetic but into heat, another form of energy).

For same reason inital rest state of the conveyor belt does not prevent it from moving when thrust of the plane is applied.

The problem still exists that in order for the trolley to move, if you push it, the wheels move.

Answer my simple questions.


What groundspeed is the plane doing at take off?
What wheelspeed is the plane doing at takeoff?
What speed is the conveyor doing (without rewording the original quesiton, ie it matches the wheelspeed in an opposite direction.)?
What groundspeed is the plane doing?

[V8MOFO]

I'll give it a crack ay.

What groundspeed is the plane doing at take off? Not sure, this couldn't be achieved with the original set-up.
What wheelspeed is the plane doing at takeoff? There is nothing to stop the wheels from accelerating, uuum close to the speed of light?
What speed is the conveyor doing (without rewording the original quesiton, ie it matches the wheelspeed in an opposite direction.)? hmmm, same as above but in the opposite rotation direction
What groundspeed is the plane doing?Same as question 1?

[sergei]

Q1)What groundspeed is the plane doing at take off?
A1)depends on the plane but it is reasonble finite value V(off) - ground speed is relative anyway, in this case ground speed should be speed relative to ground where is conveyor based, air speed relative to plane wings is more important. At the begining the plane is at rest V(off) = 0

Q2)What wheelspeed is the plane doing at takeoff?
A2)Wheelspeed - wrong term used there is no such thing as wheel speed, Speed is scalar quantaty - as for wheels angular velocity is more appropriate. The angular velocity of the wheel is irrelevant to planes ability to take off.

Q3)What speed is the conveyor doing (without rewording the original quesiton, ie it matches the wheelspeed in an opposite direction.)?
A3) see A2) for explanation on wheelspeed. The meaning of the sensece "matches the wheelspeed in an opposite direction" can be interpreted in many ways, but logical way is: the conveyor is set to counterreact any angular motion of the wheels, if so the angular velocity of the wheel would be 0 hence the energy applied from thrust of the plain would result in motion of the conveyor belt.

Q4)What groundspeed is the plane doing?
A4) see A1

[sergei]

hey my trolley can have maglev (magnetic levitation) - wheels will not rotate as there are none, or even it can have slides... rotation of the wheels is not esential for movement (hey living things don't have wheels, most of them move, and quet efficiently I would say)

[vvega]

What groundspeed is the plane doing at take off? enough to take off (dependant on the type of plave)
What wheelspeed is the plane doing at takeoff? the wheels are not moving
What speed is the conveyor doing (without rewording the original quesiton, ie it matches the wheelspeed in an opposite direction.)? the same speed as the plane turing in a direction that is to the end of the runway
What groundspeed is the plane doing? again its accellrating to takeoff speed

[RedMist]

What groundspeed is the plane doing at take off? enough to take off (dependant on the type of plave)
What wheelspeed is the plane doing at takeoff? the wheels are not moving
What speed is the conveyor doing (without rewording the original quesiton, ie it matches the wheelspeed in an opposite direction.)? the same speed as the plane turing in a direction that is to the end of the runway
What groundspeed is the plane doing? again its accellrating to takeoff speed

The wheels are not moving, the conveyor is not moving. So my original questions stand. How does the plane take off without moving the wheels? IE Skidding?

[RedMist]

hey my trolley can have maglev (magnetic levitation) - wheels will not rotate as there are none, or even it can have slides... rotation of the wheels is not esential for movement (hey living things don't have wheels, most of them move, and quet efficiently I would say)

So you have seen lots of planes with mag lev? Or the question states that the plane is elevated or in flight when it attempts to make takeoff speed?

[RedMist]

Q1)What groundspeed is the plane doing at take off?
A1)depends on the plane but it is reasonble finite value V(off) - ground speed is relative anyway, in this case ground speed should be speed relative to ground where is conveyor based, air speed relative to plane wings is more important. At the begining the plane is at rest V(off) = 0

Q2)What wheelspeed is the plane doing at takeoff?
A2)Wheelspeed - wrong term used there is no such thing as wheel speed, Speed is scalar quantaty - as for wheels angular velocity is more appropriate. The angular velocity of the wheel is irrelevant to planes ability to take off.

Q3)What speed is the conveyor doing (without rewording the original quesiton, ie it matches the wheelspeed in an opposite direction.)?
A3) see A2) for explanation on wheelspeed. The meaning of the sensece "matches the wheelspeed in an opposite direction" can be interpreted in many ways, but logical way is: the conveyor is set to counterreact any angular motion of the wheels, if so the angular velocity of the wheel would be 0 hence the energy applied from thrust of the plain would result in motion of the conveyor belt.

Q4)What groundspeed is the plane doing?
A4) see A1

Q1 Agreed takeoff groundspeed is variable based on the aircraft. However your clarification between groundspeed and airspeed is irrelivant. In this instance they are one and the same thing. Please re-read post number 1.

In addition if we take V = 200 kph the wheelspeed is 200kph the conveyor is -200kph the groundspeed = 0. If we take 300 kph, 1000kph, 10000kph ... you get my point.

Q2. I wholeheartedly dissagree with you. There is such a thing as wheel speed, just because you don't understand a concept doesn't mean it doesnt exist. Speed is a scalar, however the question stated "opposite direction" which gives it a directional vector. Are you attempting to skew the travel to conveyor angles? If so it states opposite direction.

In addition you are saying that planes taking off on a standard runway don't need to rotate wheels? As it's irrelivant then surely it shouldn't matter in a standard situation either. So why do planes have wheels if they arent designed to go around?

Q3. If wheelspeed matches conveyor speed in reverse. Then how can the conveyor move if the wheels don't?

In regards to your thrust theroy. Lets take the trolley example. I'm standing on platform behind a conveyor. The trolley is on the conveyor, and I'm going to give the trolley a shove.
I very lightly push the trolley, the chassis flexes minutely, I attempt to gain forward momentum, the wheels begin to turn, the conveyor instantly matches the wheels in an opposite direction. As the conveyor moved under the wheels the wheels further accelerated, which in turn accelerated the conveyor. But I havent moved an inch. So I push harder, I'm attempting to move the wheels faster than the conveyor in order to "move", however no matter what force I put into the trolley the wheelspeed is always opposed by the conveyor speed. So I strap a rocket engine to the trolley. Ignite it. The trolley wheels accelerate exponentially to a point where they begin to slide. At which point the trolley wheels will be doing say 300kph and the conveyor 300kph but with a 20kph skid, the groundspeed will be 20kph.

[sergei]

you are saying that "conveyer matches the wheelspeed in opposite direction", please explain how conveyer could rotate in opposite direction of the wheels if there is no slip??? What you will be pushing in your case, if conveyer is designed to counterreact movement of the wheels, is the conveyer belt with the trolley on it. I will repeat myselft again, there is nothing restricting the conveyer belt from moving forward with the trolley (or plane), as long as the control unit satisfies the condition that conveyer compensates for wheel movement.

[sergei]

plane will take-off.
conveyor is irrelevant.
resistance is futile.
you will be assimilated.







I will stop my arguments now, as clearly the question is contradictory and flawed. People can't understand my logical reasoning behind it, so it is pointless to say anymore.

[RedMist]

you are saying that "conveyer matches the wheelspeed in opposite direction", please explain how conveyer could rotate in opposite direction of the wheels if there is no slip??? What you will be pushing in your case, if conveyer is designed to counterreact movement of the wheels, is the conveyer belt with the trolley on it. I will repeat myselft again, there is nothing restricting the conveyer belt from moving forward with the trolley (or plane), as long as the control unit satisfies the condition that conveyer compensates for wheel movement.

Say what?

So the conveyor moves but the wheels don't? I'll repeat myself again and state the original question again.

"The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation. "

I cant word it any other way. There is NO MOVEMENT. It simply can never happen without disparity between speed of the wheels and conveyor speed, or slip.

Or are you stating that I am now pushing the entire mechanism? Much as the thrust of the plane would accelerate not only the plane, but an entire runway sized conveyor to takeoff speed?

Think of a takeoff speed. Say 200kph and apply my original questions.

I'll do the same to attempt to clarify how you accomplish this amazing feat of taking off.

What groundspeed is the plane doing at take off? 200kph
What wheelspeed is the plane doing at takeoff? 200kph (I believe considerably more than this, however lets not complicate matters)
What speed is the conveyor doing (without rewording the original quesiton, ie it matches the wheelspeed in an opposite direction.)? - 200kph
What groundspeed is the plane doing? 0 KPH!!!!!!

[vvega]

What groundspeed is the plane doing at take off? enough to take off (dependant on the type of plave)
What wheelspeed is the plane doing at takeoff? the wheels are not moving
What speed is the conveyor doing (without rewording the original quesiton, ie it matches the wheelspeed in an opposite direction.)? the same speed as the plane turing in a direction that is to the end of the runway
What groundspeed is the plane doing? again its accellrating to takeoff speed

The wheels are not moving, the conveyor is not moving. So my original questions stand. How does the plane take off without moving the wheels? IE Skidding?

no the conveyer in moving
in order to stop the wheels from spinning the conveyer is rotating in the oposite direction to there rotation

this means that the conveyer is rotating in the same direction the plane is moving


remeber the conveyer matches the wheelspeed not the ground speed of the plane

==================>>>> planes moving this way

=================<<<<< bottom of the wheels would need to move in this direction for the plane to move forward

================>>>>> coveryer would have to move in this direction (the same way the plane need to go to take off to stop wheel motion


so the conveyer would do its job matching wheelspeed in the oposite direction
but teh side effect is that it would also be moving in the direction that the plane needs to go

but because the plane would be moving and the ground would be moving at the same speed
the wheels would not be moving....no need to skid because the ground is moving at the smae speed matching what would be the normal wheelspeed


probably sounds like babble but thats my understand of what would happen


v

[sergei]

Second that.
This is exaclty the way I see it hapening!