You're avoiding the question.

Would the plane be able to keep from moving backwards due to the friction? And, because of that, stay in one place (since it's only matching, not overcoming)?

If the plane's engines were throttled up only enough to equalize the friction produced by the wheel bearings, then, yes, you could have a plane sitting motionless on a moving conveyor belt.

Bingo. It's the same thing.

It doesn't matter which one started the event - either way, there is an equal and opposite reaction.

HOWEVER, since the original scenario specifies that the plane must have some kind of speed so that the conveyor can reverse-match it, how do you want to measure speed? In order for the conveyor to even get going, the plane would have to have some kind of ACTUAL speed...

Heck no!

The plane moves absolutely!

It's thrusters push against the atmosphere.

Please read above!

F = ma

a = F/m

That's the whole crux of it, though.

What's the speed relative to?

The one thing that needs more discussion and examination in this debate is the plane's relationship with the outside air in the atmosphere.

I don't see anything else that warrants attention at this point in the debate.

I'm specifically talking about the air on the wings while the plane is at full thrust and the conveyor and speed of the plane are perfectly matched. I'm not concerned with the air behind the engines at this point or the engines effect on that air behind the plane.

I've noticed that those who are proposing that the plane will take off seem to be assuming that the plane in the scenario has an identical relationship with the atmospheric air as a normal plane going down a runway in a conventional takeoff.

I believe that is a premature and most likely incorrect assumption. You are possibly looking at the problem merely in practical terms and not considering the more complex aspects.

I'm not saying you are wrong... but, as far as I can see, that should be the primary and only focus in the debate at this point.

If I run on a treadmill at 4mph for one hour, I don't move relative to the room I'm in.

But I don't tell someone, "I ran zero miles today!"

I DID run 4 miles.

There is ZERO power being put directly to the wheels. They just spin. In fact, the plane can take off while the wheels are actually spinning backwards due to the fact that the wheels have no effect on propultion.

Ever wondered why no one has ever seen a jet on a dyno?

I also used the Harrier reference because there are two forces at work there. First it uses downword thrust to achieve lift, and then forward propultion to achieve speed.

Try to imagine a hovering Harrier. It is hovering in mid air and then when maximum thrust is applied to forward motion it reaches speed and is no longer reliant on downword thrust to defy gravity. But by "floating" it is eliminating the need for a runway, thus no need for wheels. Yet, from a standing start, mid air, it is able to achieve flight.

No bearing on this debate but interesting nonetheless...

On November 27, 1970, a Capitol Airways DC-8 crashed on takeoff at Anchorage, killing 47 of the 229 aboard. From the report:

PROBABLE CAUSE: "The failure of the aircraft to attain the necessary airspeed to effect lift-off during the attempted takeoff. The lack of acceleration, undetected by the crew until after the aircraft reached V1 speed, was the result of a high frictional drag which was caused by a failure of all main landing gear wheels to rotate. Although it was determined that a braking pressure sufficient to lock all of the wheels was imparted to the brake system, the source of this pressure could not be determined. Possible sources of the unwanted braking pressure were either a hydraulic/brake system malfunction or an inadvertently engaged parking brake."

It is NOT able to achieve flight from a mid air standing start. The vents gradually turn as the plane begins moving forward.

Try taking that harrier and switching the vents instantaneously from vertical to horizontal.

It's going to drop like a rock. Because there is no lift on the wings.

There, you are making the assumption that the harder the engines pull, the force of friction on the wheel bearings equalizes the engine thrust. Your response assumes that the wheel bearings would have an infinite amount of friction that is opposed by an infinite amount of engine thrust. In real life, of course, we know that at some rotational speed, the tires would fly apart or the wheel bearing grease would overheat and cause the landing gear to self destruct.

DING DING DING DING DING!!!! It's IMPOSSIBLE to put a plane on a dyno without strapping it down so it doesn't move forward! The conveyor belt scenario is basically a theoretical dyno tester!

The plane is moving.

You haven't answered the question. I'll put it another way....

If an outside observer were to look at the hypothetical experiment being discussed while it is in progress... keep in mind that the conveyor and the plane's speed are matched...

Tell me what that outside observer would see? Describe the scene from their eyes.

They would see a plane get onto a runway, jerk forward for a microsecond, then move very slowly forward until the tires and wheel bearings got too hot and self-destructed. Then they'd see some emergency vehicles and eventually an evacuation of the aircraft.

At what moment is vertical thrust insignificant and horizontal thrust applied? Aren't we still talking about achieving maximum thrust in flight without the use of the wheels making the wheels irrelevant.

I still think it would take off in the conveyor scenario, but why is it that jet pilots appply thrust gradually as opposed to appplying full throttle and reducing runway distances? Isn't the thrust alone enough to push the plane into flight?

Does the plane on the conveyor belt also create it's own atmospheric conditions like a tornado? Althought it appears that it is not moving it of course we know that it is. Due to speed and friction of the wheel is there enough motion to create wind and simulated atmosphereic conditions of movement?

It seems to me that the "will take off" crowd is right...IF the plane was already airborne. But to get airborne, it must move forward relative to the ground and surrounding air. It's not doing that on the belt, just like the runner on the treadmill doesn't advance relative to the room.

I think whoever said the question of what speed means in this instance is right. Can the belt really "match" the plane's speed, and if so, what exactly does that mean? To me it means it negates the plane's forward motion, just like a dyno does to a car or a grocery store conveyor does to an orange.

That's funny.

In all seriousness, the others need to answer that question. It will help us all get on the same page.

I have a truck
Do you give a fuck?
Maybe it needs cleaning
Maybe this has another meaning
Do you know what it is yet?

That question I can answer: engine wear. Maximum thrust is not used by airliners for takeoff, "takeoff thrust" is computed using the final weight and balance figures and is usually not maximum thrust but a percentage thereof. This minimizes engine wear and allows a safety cushion of available power if needed.

You are getting VERY CLOSE.

The plane is in motion. However not in conventional terms.

We need to know the exact relationship of the plane and the atmospheric air at this point in time.

How can a conveyor belt touching wheels that have no power source negate movement caused by engines pushing against air?

So if necessary, and engine life were not a factor for this excersize, you could potentially go from zero to takeoff thrust with wreckless abandon set the wing flaps for takeoff and...

Take off. Right?

It's also to make it more comfortable for passengers as well as to reduce stress on the airframe. Theoretically it could be possible for a plane to be made with engines so powerful that they could rip themselves from the wings if they were turned on full blast while the plane isn't moving.

Not immediately. You have to have foward momentum to get wind going across the wings.