OT Plane on a conveyer belt

[Scott_T]

This is a typical reference frame error. The plane is not powered by it's wheels, it is powered by either a propellor or a turbine relative to the air. The thrust is placed into the air, not the conveyor. The conveyor can match the planes speed in reverse, that just means that the wheels are turning twice as fast as the plane is moving relative to the air. No matter how fast the conveyor moves, the plane still moves relative to the air. Hence, it will take off. This is a classic mis-direction brain teaser. The one caveat is that if the friction in the wheel bearings/tires create drag equal or greater than the thrust, then the plane cannot accelerate to take off. Of course that would be moot, as the wheels/tires would catch fire, and there would be a big boom fed by aviation fuel.

Bingo! I thought exactly the same thing when I read it, but I had to read the 4 pages of posts before replying!

 

[brucedurham]

i think it would take off! i also think if your in an elevator ,and it breaks free 20 floors up.all you have to do is jump up as hard as you can right before it hits and you wouldnt even get a scratch

 

[topfuel443]

I also think if your in an elevator ,and it breaks free 20 floors up.all you have to do is jump up as hard as you can right before it hits and you wouldnt even get a scratch

Hmmm..... interesting. That would be a good one for mythbusters....

~James

 

[t_hedlund]

mythbusters has already done the the elevator, And it was busted, You cannot jump fast enough!!

As far as the plane if the conyer keeps up with the throttle it will never take flight no air acrossed wing = no lift.

If you get on a tread mill ( conyer belt) and run at 20mph and stick your hand out straight from your side. You will feel hardly any wind, Now hop in your car and drive 20mph and stick your hand out , you will feel lift. The camper isn't the same situation.

 

[topfuel443]

The airplane takes off... I thought we already put that one to bed?

I guess there is still more debate.

~James

 

[Andy Greene]

i think it would take off! i also think if your in an elevator ,and it breaks free 20 floors up.all you have to do is jump up as hard as you can right before it hits and you wouldnt even get a scratch

Let me know how that works out for you

 

[piper_chuck]

mythbusters has already done the the elevator, And it was busted, You cannot jump fast enough!!
As far as the plane if the conyer keeps up with the throttle it will never take flight no air acrossed wing = no lift.

If you get on a tread mill ( conyer belt) and run at 20mph and stick your hand out straight from your side. You will feel hardly any wind, Now hop in your car and drive 20mph and stick your hand out , you will feel lift. The camper isn't the same situation.

Answer me this. When the engines of the plane are applying thrust against the air, what counter force keeps it from moving forward? The answer is there is no counter force, except a small amount of friction from the wheel bearings. This is the reason why the plane will move forward, and will achieve takeoff speed.

 

[TomMoorehouse]

I think the people that believe it will fly, believe it will move forward. The people that believe it will not fly, believe it will not move forward.

I don't believe it will move forward.

 

[piper_chuck]

What prevents it from moving forward?

 

[Dan Hydro]

I think we can blame it on the 3/4" pin rubbing against the calipers, thus causing the bearings to overheat.

Dan.

 

[Propjockey]

The plane will move forward until it gains enough AIRSPEED to fly. If the engines were connected to the wheels and the conveyor exactly matched this propulsion, the plane would not gain airspeed. But the engines aren't connected to the wheels. The engines push against the air and don't give a rat's A** what the wheels are doing.

Take Preston's example of putting wings on his car and then putting the car on the conveyor. Propulsion is provided by the wheels. If the conveyor matches this propulsion, the car remains stationary. Now, put the car in neutral and strap a jet engine to the roof. It will accelerate forward until there is enough airspeed over the wings to provide lift and fly.

B)

 

[Nigtmare]

next wed.@ 9pm myth busters will have a R/C plane on a conveyor to see if it will take off...

don't forget to watch.

Nick

 

[moparbarn]

i saw that ad, too. they showed full size planes, also. don't know if they will try those or not. i'll be watching this wednesday to see the plane fly off the belt.

 

[Advance_United]

A plane is standing on a movable runway( something like a conveyor).as the plane moves the conveyor moves but in the opposite direction.the conveyor has a system that tracks the speed of the plane and matches it exactly in the opposite direction.
The question is, will the plane take off or not?

This question may have been seen by many of you, but it has caused debate beyond belief. lets hear it...

~James

The key to this puzzle is to understand the Frame Of Reference used to describe the situation. The question clearly states that the plane is moving, for sake of discussion, in the +X direction. It also states that the conveyor is moving in the opposite or -X direction. For this to be the case the Frame Of Reference has to be at fixed location, not some point on either the conveyor or the plane.

For example, if you are standing stationary on the people mover in the airport your speed relative to the mover will be zero. However, to an observer standing next to the mover your speed will be that of the moving belt. It's all a matter of your Frame Of Reference.

The question establishes that the plane is moving. The conveyor is moot. The plane will be able to make a normal take-off.

Bob Heywood

Dayton, OH

 

[Advance_United]

Delete-double post

 

[dwb2620]

Here is what will really happens!

The plane will crash and burn after attempting to take off. The tires will explode from overheating, due to spinning faster than they were designed. Hot pieces of tread will rupture the fuel tank and ignite the fuel. The conveyor belt and the airplane will be destroyed. Lawsuits will arise blaming the conveyor belt manufacturer, The airplane builder, the tire maker, the fuel producer, and the creator of the "Plane on a Conveyor belt" idea. There will be no winners (just whiners) and everyone will move on to the next Brain Twister such as:

When a fly lands on a ceiling, does it execute a barrel roll or an inside loop?

Thank you for your time,

David

 

[Don Ferrette]

Here is what will really happens!
The plane will crash and burn after attempting to take off. The tires will explode from overheating, due to spinning faster than they were designed. Hot pieces of tread will rupture the fuel tank and ignite the fuel. The conveyor belt and the airplane will be destroyed. Lawsuits will arise blaming the conveyor belt manufacturer, The airplane builder, the tire maker, the fuel producer, and the creator of the "Plane on a Conveyor belt" idea. There will be no winners (just whiners) and everyone will move on to the next Brain Twister such as:

When a fly lands on a ceiling, does it execute a barrel roll or an inside loop?

Thank you for your time,

David

Hmmm, similar to my theory back on post #9-http://www.intlwaters.com/index.php?s=&amp...st&p=212462

:lol: :lol: :lol: :lol: :lol:

 

[ntm]

I didn't know the jet engines pushed the plane on the runway. I always thought there was a huge transmission with lots of gearboxes, shafts, and linkages that went to all the wheels, and all those black tire marks on the runway tarmac were from young pilots doing high RPM neutral drops and massive landing gear burnouts when the air traffic controllers weren't looking. :blink:

No doubt !

I can't believe there's even a conversation over this, the answer is so elementary it's painful.

Bottom line is that ground speed is irrelevent, the only energy being absorbed by the "treadmill" is that of frictional losses within the wheel bearings. Easily overcome by the jet engines and the jet proceeds to launch itself off of the treadmill into flight.

 

[LarryConrad]

I also think if your in an elevator ,and it breaks free 20 floors up.all you have to do is jump up as hard as you can right before it hits and you wouldnt even get a scratch

Hmmm..... interesting. That would be a good one for mythbusters....

~James

It's on Mythbusters this week.

 

[dwb2620]

Here is what will really happens!
The plane will crash and burn after attempting to take off. The tires will explode from overheating, due to spinning faster than they were designed. Hot pieces of tread will rupture the fuel tank and ignite the fuel. The conveyor belt and the airplane will be destroyed. Lawsuits will arise blaming the conveyor belt manufacturer, The airplane builder, the tire maker, the fuel producer, and the creator of the "Plane on a Conveyor belt" idea. There will be no winners (just whiners) and everyone will move on to the next Brain Twister such as:

When a fly lands on a ceiling, does it execute a barrel roll or an inside loop?

Thank you for your time,

David

Hmmm, similar to my theory back on post #9-http://www.intlwaters.com/index.php?s=&amp...st&p=212462

:lol: :lol: :lol: :lol: :lol:

Great minds think alike! :lol:

Oh yeah, just FYI, mailed you a check today for one of your mixture controls for a 21/45 engine size. I am replacing one (not yours) that is worn out. I have a race in a couple of weeks.

Later,

David