FLY or NO FLY

[NOS2006]

What? No... We're 9th cousins, three times removed.

Which means.. you're not related!

[capriceman]

model airplanes arent scale though. Since they can create Extreme amounts of lift and be light as hell. The plane would have to be made of Depleated Urainum (sp) for it to be scale.

[Satty]

BTW, they tested this on Mythbusters and the plane flew.

[daves87rs]

BTW, they tested this on Mythbusters and the plane flew.

Cool....

[Intrepidation]

Since the original link doesn't work, to what are we referring?

[daves87rs]

Since the original link doesn't work, to what are we referring?

Don't know...

[Satty]

The question was: Will an airplane on a treadmill (i.e. stationary) with the engine running take off? The answer is yes. Mythbusters link

[Intrepidation]

Haha, a lot of people got pwnt.

Makes perfect sense, since the propeller is the one moving the plane and not the wheels.

[Sixty8panther]

Propeller?

Since when was this a propeller driven plane???

I thought it was a jet!

[Sixty8panther]

OK, so wind isn't the right term. No flow of air around the airfoil (wing), no lift, no flight, no exceptions.

This principle is still 100% sound, and THAT was the point.

[Intrepidation]

Propeller?

Since when was this a propeller driven plane???

I thought it was a jet!

Well this is the first time I have ever heard of this myth, and the planes they tested were propeller driver. The same principle applies to turbofan, turbojet, turboprop, and so on engines if you want to be technical.

[Sixty8panther]

The question was: Will an airplane on a treadmill (i.e. stationary) with the engine running take off? The answer is yes. Mythbusters link

That is a teaser video, the question is not answered, am I missing something?

Once again, the propeller does NOT create lift, it moves the plane forward at

high speed which moves air under & over the wings & that (& ONLY that)

creates lift in a fixed wing airplane.

(this obviously excluding the Harrier Jet, Helicopters etc.)

[Intrepidation]

Youtube is your friend.

The thrust produced by, in this case, the propeller, drives the plane forward and not the wheels. This allows the plane to continue to move and therefore build lift.

[Sixty8panther]

Youtube is your friend.

The thust produced by, in this case, the propeller, drives the plane forward and not the wheels. This allows the plane to continue to move and therefore build lift.

you need to REREAD the thread. I KNOW what does & does NOT drive a plane.

I was up on the ins & outs of aviation by the age of 11/12.

[Intrepidation]

Yes of course silly me, you know everything there is to know and I must not know anything.

[PurdueGuy]

Ok, if I recall correctly, the original question goes something like this: the conveyor will automatically increase in speed to instantly compensate for any forward motion of the airplane, right?

If an airplane is sitting on a platform, engines off, no brakes activated, and you move the platform, does the airplane move with the platform? Yes, unless the platform moves out from under it suddenly. Why? Because of friction in the bearings of the wheels. If you remove all friction from the equation, the inertia of the airplane would mean that the wheels, which have no friction except between the rubber and the platform, would rotate, and the plane would not move in spite of the platform moving. If you then apply those same assumptions (there is friction between the tire & surface, there is no friction in the bearings), then the movement of the conveyor has no bearing whatsoever on the motion of the body of the airplane. Thus, if another force is applied to the body from the plane's engine, it doesn't matter what the conveyor does, the plane will move forward.

In (almost) real life, there is friction in bearings. So, if we assume that the conveyor has no limit on its acceleration, then the instant that the plane begins to move, the conveyor would instantaneously increase in speed to an infinite amount trying to counteract the movement of the plane, until the bearings simply exploded and the plane fell on the ground.

Conclusion: the answer to this puzzle depends completely on how the puzzle is worded, and the assumptions you make, but in general, the force introduced into the system by the conveyor does nothing but spin the wheels, it does not move the body, and the plane will still take off.

[Intrepidation]

I want to do this with the Super Cub for fun.

[Sixty8panther]

Sorry to come off as a dick, but I agree w/ Purdue:

It's all in the wording.

DF: I was put off by your "people got owned" comment

when in this instance Mythbuuster's attempt to solve the

riddle was lame & not at all sufficient to be considered

a tie breaker. A sheet of canvas pulled by a pickup is

NOT at all even close to the hypothetical conveyor belt

the original question describes.

[Satty]

It was tested in reality, and it was debunked in reality. You're more than welcome to develop this hypothetical conveyor and prove everybody wrong, but I'm not going to hold my breath. While you're at it, you can also disprove Schrödinger's cat, since you're obviously brilliant when it comes to quantum mechanics.

[ocnblu]

Quantum mechanics are a dying breed, as most Quantums are in the junkyard by now.

[Intrepidation]

Quantum mechanics are a dying breed, as most Quantums are in the junkyard by now.

--

It's worth noting that, for those who require an actual conveyor belt, but like the rest of the world don't have the money, time, or care to do a full size 100% ZOMG conveyor belt, they did test it on a scale model (before they did the full scale test) with an "actual" conveyor belt and the results were the same.

[Sixty8panther]

In theory, we could be telleporting $h! by now.

So says much of science.

So why are we shipping goods on cargo ships

& still flying on B-747s?

Einstein's theory of relativity was the

catalyst for the Atom bomb, and it also says

time travel is possible. I'm still waiting.

IF there is no movement of the plane as relative

to the conveyor belt & ground, and therefore

the air-speed remains at ZERO, the place can

NOT fly. That's absolute fact. LIFT in a

conventional aircraft "fixed wing" is not possible

without a given airspeed....

Saying $h! like "the airflow/thrust of the propeller

would allow lift in under the wings" is so dumb it

makes my brain hurt.

It's the aviation equivalent of the whole "you're in

an elevator that is falling at terminal velocity so

you jump just a split second before impact and

survive without a scratch..." scenario.

Edited June 10, 2009 by Sixty8panther

[PurdueGuy]

[quote name='Sixty8panther' date='Jun 9 2009, 10:03 PM' post='5IF there is no movement of the plane as relative

to the conveyor belt & ground, and therefore

the air-speed remains at ZERO, the place can

NOT fly.

There. Right there is where you miss the point. You are assuming the conveyor is able to keep the plane at a speed of zero relative to the ground. And that assumption is wrong. All the conveyor can do (friction aside because it's a hypothetical question) is make the free-spinning wheels spin faster. The speed at which the wheels spin has nothing to do with the speed of the airplane since the wheels do not propel the airplane.

[daves87rs]

This is still going?

[Intrepidation]

[quote name='Sixty8panther' date='Jun 9 2009, 10:03 PM' post='5IF there is no movement of the plane as relative

to the conveyor belt & ground, and therefore

the air-speed remains at ZERO, the place can

NOT fly.

There. Right there is where you miss the point. You are assuming the conveyor is able to keep the plane at a speed of zero relative to the ground. And that assumption is wrong. All the conveyor can do (friction aside because it's a hypothetical question) is make the free-spinning wheels spin faster. The speed at which the wheels spin has nothing to do with the speed of the airplane since the wheels do not propel the airplane.

This

[Intrepidation]

In theory, we could be telleporting $h! by now.

Also this: Scientist Teleport Matter More Than Three Feet

[Sixty8panther]

(friction aside because it's a hypothetical question)

The friction is a factor YOU choose to ignore.

That's conveniently selective.

In YOUR opinion friction is hypothetical but

yet the conveyor able to keep up with this

known control is also hypothetical.

Once again, I'm not saying I do not see both

sides, but some people's wording is incorrect.