AirPlane on a Teardmill and Mythbusters

[khaddon2110]

This thread is like watching a monkey hump a football.

There's a lot going on, but not much happening. And THAT is philosophical way to look at THAT.

LOL

LOL! Kind of like Fosies Avatar

 

[Supplicate]

 

[Mafesto]

 

[EastcapeAngler]

One last attempt

OK. This is my last attempt to convince all doubters that the plane flies.

Let's compare the scenario to a car..... A car(2 wheel drive, rear wheel.) has a propulsoin system, a motor. Let's say,1,000HP. A plane has a propulsion system,a motor.50,000HP. Both the plane & the car have wheels. The propulsion system on the car is connected to the wheels of the car. The WHEELS of the car propel the car forward, NOT the motor. If you disconnect the driveline, you still have 1,000hp, but you ain't gonna go anywhere! ... The plane's wheel's ain't connected to the propulsion system whatsoever!. The motor on the plane,50,000hp, propels the plane,NOT the wheels! The wheels are just "there". The plane starts to accelerate, reaching 200MPH. That means the wheels are spinning at what amounts to 200MPH. The treadmill is matching the 200mph wheel speed...BUT, niether the belt,NOR the wheels caused the 200mph wheel speed, the thrust from the plane's motors produced the 200mph. Not the wheels!!!! The wheels are,in reality, spinning at 400mph! The plane is pushing them to the 200mph in a rotation, while the belt is trying to spin the wheels 200mph in the same rotational direction. Don't you get it?? If you put the car on the belt,the wheels try to propel the car forward,but if the car's wheels are spinning at 50mph. & the belt matches that 50mph,it goes nowhere because the belt is matching one on one the propulsion source from the car! BUT, with the plane it is only matching one on one the wheel spin produced by thrust,NOT the thrust itself.

 

[Supplicate]

No. First of all, a propeller driven aircraft moves forward because each propeller blade is an airfoil. As the propeller spins, it creates "lift" in the forward direction. Yes, it displaces air backwards, but not enough to move the plane very much by action/reaction, and the prop blast does not create any appreciable lift on the wings.

A jet powered aircraft generates thrust from the ejection of mass (exhaust) at high speed and uses Newton's law, i.e. action/reaction.

If the conveyor belt's speed increases or decreases so that ground speed remains zero, then there is no airflow over the wings and the plane will not fly.

To turn this around, assume the plane didn't have a propulsion system at all. Reverse the conveyor belt so that it is carrying the plane forward, generating an airflow across the wings. If you continue to increase the speed of the conveyer belt, at some point there will be sufficient airflow for the plane to lift off. Momentarily. As soon as lift exceeds the friction between the wheels and the conveyor belt, the plane lifts up, but then it stalls as the speed drops. So the plane would basically start little hops and never go any faster, no matter what the speed of the conveyer belt.

So hows that sit with some of you

And then:

Think about a plane taking off on ice, with all the wheels locked

The plane would still accelerate, even though the wheels are not moving.

So the argument continues

I don't really care either way, from the commercial I'm pretty sure that Mythbusters will prove that the plane will take off.

 

[Superdutytd]

This boggles my mind that someone thinks it can't take off.

There was an argument on another forum about what would happen if there was no friction in the bearings or the conveyor belt, would the tires spin to an unlimited speed as the plane was moving forward by the thrust from the jet engines?

 

[H2SNOW]

This boggles my mind that someone thinks it can't take off.

There was an argument on another forum about what would happen if there was no friction in the bearings or the conveyor belt, would the tires spin to an unlimited speed as the plane was moving forward by the thrust from the jet engines?

I don't think that it will take off .......boggle boggle boggle

 

[sortastock]

move forward in relation to...

the conveyor? won't take off
the earth's surface? will take off
you? depends on which direction you are headed and at what speed
a bird flying the oposite direction? might take off.

...

relative motion? being rooted? to what? and the birds-what?? NO! Sum the forces! Draw a little FBD. don't add variables, don't talk about birds. Draw a FBD, sum the forces. You'll notice that the forces do not equal zero, the plane is not static, the plane moves forward, and takes off.

don't even think about flying, since that is apparently too difficult. Think about a plane without wings, only a force pushing on the back of the plane. doesn't matter how it's being applied. It only matters that it's being applied to the plane, not the wheel. So, you've got the force pushing on it on your fancy FBD... what else? NOTHING (besides normal). The forces don't balance, the plane accelerates forward. don't make me whip out paint and draw a fbd lol

 

[RMK7SledHead]

relative motion? being rooted? to what? and the birds-what?? NO! Sum the forces! Draw a little FBD. don't add variables, don't talk about birds. Draw a FBD, sum the forces. You'll notice that the forces do not equal zero, the plane is not static, the plane moves forward, and takes off.

don't even think about flying, since that is apparently too difficult. Think about a plane without wings, only a force pushing on the back of the plane. doesn't matter how it's being applied. It only matters that it's being applied to the plane, not the wheel. So, you've got the force pushing on it on your fancy FBD... what else? NOTHING (besides normal). The forces don't balance, the plane accelerates forward. don't make me whip out paint and draw a fbd lol

are you playing internet enginerd again? seriously...fbd's? there's like 7 guys on this whole site who would understand an fbd.

 

[sortastock]

are you playing internet enginerd again? seriously...fbd's? there's like 7 guys on this whole site who would understand an fbd.

LOL 7 doesn't seem too far off sometimes...

 

[Mtn Cat 900]

So..... if you started the treadmill before the jet engines...... ? Would the jet not move backwards until it fell off the treadmill ??????

Stirring

 

[Supplicate]

are you playing internet enginerd again? seriously...fbd's? there's like 7 guys on this whole site who would understand an fbd.

heh, I don't feel like messing with free body diagrams when its more fun to just stir the pot

 

[EastcapeAngler]

with him as a pilot???

Whether or not it flies,,I ain't takin his flight if he's drivin!!!!!

http://www.youtube.com/watch?v=vLBKOcUbHR0&feature=related

 

[KidWalleye]

It Wont Fly

OK the tredmill is there to stop all forward movment of the plane it doesnt matter how fast the wheels are turning. the plane has no foward movment there for there is no lift. if you beleive it can take off on a tredmill them you must also believe that it can take off just sitting on the run way. what it is just going to jump up in the air and fly.

Gary

 

[EastcapeAngler]

OK the tredmill is there to stop all forward movment of the plane it doesnt matter how fast the wheels are turning. the plane has no foward movment there for there is no lift. if you beleive it can take off on a tredmill them you must also believe that it can take off just sitting on the run way. what it is just going to jump up in the air and fly.

Gary

Planes can't jump gary.

 

[Meatman]

bwahhaah ya i got to thinkin about it, i dont think it will fly either

 

[Boondockercat]

no windspeed

no lift

no fly

that simple

 

[EastcapeAngler]

no windspeed

no lift

no fly

that simple

..In order to have an arguement, both sides require mental output... You sir, have no grey matter. Therefore I cannot joust with you.

 

[Abominable]

Arguing this topic is exactly like competing in the special olympics: even if you win you are still retarded. Super retarded.

 

[phatty]

and this one time in physics class, we learned about force and mass and acceleration and friction and vacuums and vectors and gravity...

How long of a treadmill runway are we talking here? it better be at least double the size of a real runway...

do they serve peanuts on the flight?

its simple math people...

if the force propelling the plane forward is greater than the force of the friction between the wheels and runway and air friction (unless were in a vacuum then air friction is negligable), then eventually the plane flies... but it might have to be a freaking huge treadmill runway...

if the force propelling the plane forward is less than or equal to the force of the friction between the wheels and runway, then the plane never flies...


What if the airplane experienced a tailwind that increased exactly the speed of the airplane, would the plane fly?