Is it just me or are people fucking thick?

[Guru-Meditation]

where would the pixies sit?

The arrow firing ones? They're behind the plane.

[Mir Nyet]

where would the pixies sit?

At the airport bar arguing about if a stationary aircraft can take off at full thrust of course

[piku]

Thank you.

Hmm... interesting leaps of logic there

Replace the wheel with the airplane's wheels. Replace the force that you exert against the ground by that of a jet engine. WATCH PLANE TAKE OFF.

Is clearly incorrect. If the jet engine had to exert a force against the ground the plane would get to a certain height and then hover. Planes quite obviously do not do this. Neither do rockets (rockets fly because of Newton's second law. The engines could consist of pixies throwing handfuls of dust out at supersonic speeds and the effect would be the same)

You also quite cleverly prove, in this bit:

If it travels the same speed as the bottom of the wheel, which is in contact with the ground, then it doesn't move at all BECAUSE THE BOTTOM OF ANY WHEEL HAS A SPEED RELATIVE TO THE GROUND OF ZERO. Otherwise it would be SLIPPING. In this case, the treadmill could easily be replaced by the floor.

how it is the airflow over the wings that generates lift, and nothing at all to do with engines, wheels or treadmills.

Engines not needed - otherwise gliders wouldn't work
Wheels not needed - otherwise birds wouldn't work, and cars would fly.

If this whole mental exercise is confusing you, just replace "aeroplane" with "man holding onto hang-glider, running on treadmill". Quite obviously he wouldn't take off. People running on treadmills feel no wind on their face because they aren't moving through the air. No airflow, no lift. No lift, no flight.

QED

[PinkFearie]

think am gonna start a pixies rights group.

they shouldnt have to do all the hard work, when theres mortal humans to be worked to death.

[piku]

where would the pixies sit?

At the airport bar arguing about if a stationary aircraft can take off at full thrust of course

I like the mental image of a plane suddenly leaping into the sky simply because its wheels are spinning round. It's great

[disciple]

Who lives here then?

Hehe.

[Mir Nyet]

think am gonna start a pixies rights group.

they shouldnt have to do all the hard work, when theres mortal humans to be worked to death.

What about all the leftie pixies? Do they not get a group too?

[zip accident]

Mir Nyet wrote:

You can easily see this effect by holding a single sheet of A4 paper too your lower lip and blowing over the surface of the paper. The paper will rise as the air passes over the surface of the paper into the lower pressured area directly above the paper...

You are joking?

[Mir Nyet]

where would the pixies sit?

At the airport bar arguing about if a stationary aircraft can take off at full thrust of course

I like the mental image of a plane suddenly leaping into the sky simply because its wheels are spinning round. It's great

Well, duhhh, it's cos of that high pressure area under the blooming wheels, innit...

[TheGoodbyeGirl]

think am gonna start a pixies rights group.

they shouldnt have to do all the hard work, when theres mortal humans to be worked to death.

What about all the leftie pixies? Do they not get a group too?

Arnt you forgetting the middle pixies??

[Mir Nyet]

Mir Nyet wrote:

You can easily see this effect by holding a single sheet of A4 paper too your lower lip and blowing over the surface of the paper. The paper will rise as the air passes over the surface of the paper into the lower pressured area directly above the paper...

You are joking?

No actually, did you try it?

[ClankClank]

No, the airplane doesn't exert any force by pushing against the ground, it exerts force by expelling air backwards, and thus pushing the jet engine forwards. The principle is exactly THE SAME- Your feet exert a force againt the ground, backwards, the ground pushes back and exerts a force against you forwards.

The treadmill exerts very little force indeed on the axis of the wheel, and thus the plane itself. It does give plenty of angular velocity to the wheel, but almost no backwards force due to the lack of friction in the bearings.

If there was no friction in the bearing, it would be the same as the an airplane sitting on a frictionless interface- it wouldn't matter how fast the surface was moving. As it is, it's more like sitting on a very slippery interface.

The wheels are not locked to a direct drive mechanism, like a wheelchair, They are free-running instead.

The speed of the wheels has nothing at all to do with the speed of the plane moving through it's medium, the air, not the surface it's sitting on.

I'm definitely right here.

[Guru-Meditation]

where would the pixies sit?

At the airport bar arguing about if a stationary aircraft can take off at full thrust of course

I like the mental image of a plane suddenly leaping into the sky simply because its wheels are spinning round. It's great

I'm flying to Europe in a week, I'll look out for pixies trying to spin the wheels of the plane.

[~D4T45H4T~]

If this whole mental exercise is confusing you, just replace "aeroplane" with "man holding onto hang-glider, running on treadmill". Quite obviously he wouldn't take off. People running on treadmills feel no wind on their face because they aren't moving through the air. No airflow, no lift. No lift, no flight.

QED

Well that seems blindingly obvious to me too, hence the original thread title. How the hell this is 14 pages long is a mystery to me.

[PinkFearie]

where would the pixies sit?

At the airport bar arguing about if a stationary aircraft can take off at full thrust of course

I like the mental image of a plane suddenly leaping into the sky simply because its wheels are spinning round. It's great

I'm flying to Europe in a week, I'll look out for pixies trying to spin the wheels of the plane.

oooh catch me a few while your at it. you may need some bog scented undies or something to lure them