Why the plane takes off in laymans (my) terms

Originally posted by aging blitzer
What 2 steps?

Acceleration isn't mentioned. Oh no. The belt cannot change speed either then.
Wheels aren't mentioned. There goes your method determining the plane's speed.

The problem mentions a plane and the belt. IT mentions motion.

A DIRECT 1 STEP relationship of speed. After all, the one is in contact with and is supported by the other.

Plane's speed CAN be measured by airspeed (both on the ground and in the air -agreed). But you're going a step further in your assertion.

If there is no acceleration, your plane cannot fly.

If there are no wheels, what is the point of contact?

Originally posted by sugiezd
Define how you measure the planes speed - remember it must corrolate with the belt's speed.

The plane's speed is measured relative to a stationary observer and therefore also relative to the air (as the air is stationary relative to the ground and to an observer).

Originally posted by XanthosNZ
The plane's speed is measured relative to a stationary observer and therefore also relative to the air (as the air is stationary relative to the ground and to an observer).

Woah.

Where does this observer come from?

The plane and belt are mentioned, the concept of speed obviosly relates one to the other.

Originally posted by sugiezd
Woah.

Where does this observer come from?

The plane and belt are mentioned, the concept of speed obviosly relates one to the other.

No it doesn't. Standard protocol for a plane is to measure air speed. Why would you bother measuring wheel speed (which is the speed relative to the belt) as air speed is what enables you to take off and therefore is the speed of consequence.
The observer isn't required at all it just a stationary landmark.

Originally posted by XanthosNZ
No it doesn't. Standard protocol for a plane is to measure air speed. Why would you bother measuring wheel speed (which is the speed relative to the belt) as air speed is what enables you to take off and therefore is the speed of consequence.
The observer isn't required at all it just a stationary landmark.

So, you are now redefining the problem.

"A plane is standing on a runway that can move (some sort of treadmill). The plane moves in one direction, while the conveyer moves at the same speed but in the opposite direction. Can the plane take off?"

Becomes:

"A plane is standing on a runway that can move (some sort of treadmill). The plane moves relative to an observer (or stationary landmark) in one direction, while the conveyer moves at the indicated airspeed of the plane but in the opposite direction. Can the plane take off?"

The answer then becomes , yes.

What a shame it's a different problem.

If you have enough lift force at the wings, the plane lifts.
If you don't have enough lift force at the wings, the plane can't lift.

If the plane lifts or not doesn't depend of the question, only of the fact if there is enough lift force at the wings.

Why does people think this is a hard question?

Now, listen at the people who actually have flight certificate and experience of flying...

Originally posted by FabianFnas
If you have enough lift force at the wings, the plane lifts.
If you don't have enough lift force at the wings, the plane can't lift.

If the plane lifts or not doesn't depend of the question, only of the fact if there is enough lift force at the wings.

Why does people think this is a hard question?

Now, listen at the people who actually have flight certificate and experience of flying...

Thank you Biggles.

Do you have a master's in stating the bleeding obvious?

The point in question is the possibility or otherwise that the plane can move forward in absolute terms or only relative to the surface of the belt.

Originally posted by sugiezd
Thank you Biggles.

Do you have a master's in stating the bleeding obvious?

The point in question is the possibility or otherwise that the plane can move forward in absolute terms or only relative to the surface of the belt.

If it is so bleeding obvious, then why this interest of the question?

If you're not interested if the plane is lifting or not, then why not just discuss any object on wheels? Why is planes so interesting?

Originally posted by FabianFnas
If it is so bleeding obvious, then why this interest of the question?

If you're not interested if the plane is lifting or not, then why not just discuss any object on wheels? Why is planes so interesting?

Well spotted.

The fact that it's a plane is irrelevant.

It is important to some, that the wheels are not powered. I think that this too is irrelevant.

Now that you're up to speed - will YOU manage to take off'

Originally posted by sugiezd
Well spotted.

The fact that it's a plane is irrelevant.

It is important to some, that the wheels are not powered. I think that this too is irrelevant.

Now that you're up to speed - will YOU manage to take off'

"The fact that it's a plane is irrelevant."

Then, why is the title of this thread "Why the plane takes off in laymans (my) terms" when is has nothing to do with the plane and whether or not it will lift?

Originally posted by FabianFnas
[b]"The fact that it's a plane is irrelevant."

Then, why is the title of this thread "Why the plane takes off in laymans (my) terms" when is has nothing to do with the plane and whether or not it will lift?[/b]

Have it your own way.

Originally posted by sugiezd
Have it your own way.

Sorry, didn't mean to offend anyone...
Just can't understand why this is so interesting so it merits 15 pages of postings in the second thread with the same theme...

There are several theories for the principles of flight and none have been proven to be a correct and overiding explanation. Essentially it is possible for a plan to take off at a zero ground speed (or even moving backwards) so long as the oncoming wind generate sufficient lift over the wings of the plan. This of course assumes that the hurricane type winds haven't already picked up the plan and 'bowled it down the runway'. Aeroplanes always take off into wind and land into wind for this reason (the ground speed is lower).

Originally posted by FabianFnas
Sorry, didn't mean to offend anyone...
Just can't understand why this is so interesting so it merits 15 pages of postings in the second thread with the same theme...

I apologise.

Would you mind reading back a few pages and then you'll see what this is all about.

Originally posted by sugiezd
I apologise.

Would you mind reading back a few pages and then you'll see what this is all about.

Agreed - what's your point?