Will the plane fly?

[OldSchoolin86]

LMAO, the votes are tied! I love this one, it's amazing how hard it is for people to deal with the idea that the wheels on the plane... that touch the conveyor..... have nothing to do with how a plane takes off........................ the plane will take off just about the same as any other day. It will travel down the runway, build speed, take off and have wheels that are spinning twice as fast as normal.

[Dammit!]

The riddle says the planes speed and the conveyor are linked, not the wheels.

Which means the plane IS moving. If the plane is moving 180mph one way and the treadmill is moving 180mph the other way, you have 360mph wheel speed but still the normal 180mph wind speed the plane needs to fly.

It wouldn't matter if the treadmill was moving 10,000mph. The plane is still going to move forward and take off because it isn't driven by the wheels.

I saw a sneak peak of the mythbusters show and I'm afraid now that they aren't even doing it right. Looks like they put a plane on a conveyor belt, started up the belt and had the plane just match the speed of the belt. In that case OF COURSE it's not going to take off. That's retarded. The plane has to be moving through the air to take off and in the orginal question it says the belt matches the plane's speed, not the other way around. I'll be extremely disappointed in them if they do it that way.

[Dammit!]

http://www.youtube.com/watch?v=4owly...eature=related

[OldSchoolin86]

I'll be extremely disappointed in them if they do it that way.

Wouldn't be the first time they screwed up something.

[Dammit!]

Wouldn't be the first time they screwed up something.

Very true. They're gonna get roasted if they screw this one up though.

Here's the original question with the original wording for those that have not seen it.

A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction). Can the plane take off?"

The answer is in the question. The plane is moving forward. The rolling resistance of the wheels isn't going to do **** to keep the plane from blasting down the moving runway and taking off. It doesn't say anything about the belt matching the engine speed. Just the plane's speed which says right there that it's moving which would give you a wheel speed of only a few hundred miles per hour WORST CASE SCENARIO which isn't going to cause anywhere near enough friction to bother the plane.

It's also right in the question that the conveyor is being matched to the plane's speed and not vice versa.

[The Goat]

Damnit, am I correct in my assessment above? I'm nearly positive that I am.

[Jason Hall]

If they slow the plane down to match the conveyor speed, then the plane will not lift off. In that case the extra thrust that the plane does have makes no difference. I guess we will be wrong, because mithbusters won't be using enough thrust to make the plane overcome the conveyor's speed. I guess I should have made sure I understood the exact wording of the riddle.

[Dammit!]

it really all depends on how you look at it.

if the belt is doing 500...and the wheels are freespinning, the plane can take off. TRUE

if the belt is doing 500...but the wheels are not spinning, and the plane is doing 500 mph in reverse, the plane likely won't be able to take off. IT WOULD BE FUN TO WATCH

if the belt is freerolling...the plane takes off. TRUE

if the belt doesn't move at all...the plant takes off. TRUE Edit: wait a second... the plant? What kind of plant?

if the second option is tried...it's likely a few people will die. VERY TRUE

[The Goat]

thanks, I wasn't sure if i was missing some key detail or not. lol.

[dogger]

actually I'm suprised nobody hit on the real problem here WERE ARE THEY GOING TO FIND A CONVOYER THAT IS LONG ENOUGH TO GET A PLANE UP TO SPEED.thing about it the plane is going to be moving forward unless it's teatherd which defeat's the purpose. a plane needs so much room to take off. in most cases several thousand feet. the whole time the plane is throttled up it's going to moove foward regardless of what the conveyor is doing. it'll run right off the end of it.

[Banage]

If its on a moving belt, only the trires are spinning. There is no air flow, so no lift.

[Red Rider]

actually I'm suprised nobody hit on the real problem here WERE ARE THEY GOING TO FIND A CONVOYER THAT IS LONG ENOUGH TO GET A PLANE UP TO SPEED.thing about it the plane is going to be moving forward unless it's teatherd which defeat's the purpose. a plane needs so much room to take off. in most cases several thousand feet. the whole time the plane is throttled up it's going to moove foward regardless of what the conveyor is doing. it'll run right off the end of it.

I would imagine they will scale the experiment down by using a R/C aircraft.

[Billy Golightly]

Very true. They're gonna get roasted if they screw this one up though.

Here's the original question with the original wording for those that have not seen it.

A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction). Can the plane take off?"

The answer is in the question. The plane is moving forward. The rolling resistance of the wheels isn't going to do **** to keep the plane from blasting down the moving runway and taking off. It doesn't say anything about the belt matching the engine speed. Just the plane's speed which says right there that it's moving which would give you a wheel speed of only a few hundred miles per hour WORST CASE SCENARIO which isn't going to cause anywhere near enough friction to bother the plane.

It's also right in the question that the conveyor is being matched to the plane's speed and not vice versa.

I understand what your saying , but I'm just getting a different interpretation of the questions.


Chronologically:

The plane is sitting still (first 4 words)
The plane moves, while the conveyor moves in the opposite direction (so the plane does not start moving before the conveyor.)
The conveyor tracks, and matches the speed of the plane. (As thrust is increased, so is the speed of the airplane, also speeding up the conveyor )

[Dammit!]

"the plane moves in one direction"

Dude the plane is moving. Standing still is not a direction. The question doesn't mention anything about matching thrust. Just the plane's speed. The plane can't have any speed if it's not moving.

It's not a myth it's a trick question. Either that or a horrendously constructed question. By the preview I think even the mythbusters might have gotten taken in by it. If you only read what's in the question without making assumptions about it's meaning, the plane moves and takes off. If you only use enough thrust in the plane to match the speed of the conveyor (as it appears the mythbusters may have done) then you're not doing what the question asks at all. I hope they're not that retarded.

Look on youtube, the preview is on there and it shows how they used a real airplane. Several people have done scale experiments on youtube. The model planes need very little thrust to break the friction of the wheels/bearings sitting still. Once that friction is broken the plane can accelerate at will and is not affected by the treadmill at all. They can keep pace with the treadmill even as it accelerates without even increasing thrust much if at all.

It's also right in the question that the initial friction is broken other wise neither the plane or the treadmill would be moving so don't go there.

[Red Rider]

I hope the Mythbusters used a strong enough tarp for their conveyor belt. I envision the friction between the airplane's wheels & the pavement wearing a hole right through that tarp.