Will the plane take off?? Finally going to be answered.***

[hoss 5,000+ posts]

basic rundown...

force = mass x accelerarion

in order for the plane to stand still (accel = 0) there has to be an equal and opposite force applied to the plane

the treadmill will apply a force to the wheels

the wheels will spin, and convert the force, via friction, to heat.

the planes motor will exert a force large enough to cause acceleration, thus the net forces applied to the plane are not 0

please show me where an equal and opposite force is being applied to the plane, such that the net forces on the plane are equal to 0...

 

[JLJunkieMX107 10+ year member]

It is not the same as a car on a dyno, cars drive with their wheels. A plane's power comes from the engine, pushing it through the air. Air speed is different than ground speed. How were they going to make the plane stay stationary? You meant that they were going to anchor it down, so that its some kind of standing takeoff(like a helicopter)? Im not really sure what you are saying

Exactly, but in order to gain air speed, you first have to increase the ground speed to take off. Im done trying to explain this, just watch the **** myth busters!! lol

 

[IamDeMan 5,000+ posts]

OK listen its NOT a law of relativity.
OK the myth: the plane is at takeoff thrust. The treadmill is at takeoff thrust speed.

OK so lets say at thrust percent 70, the plane is able to get up to speed and take off. Thrust is a measure of air displacement force that causes motion. OK, it has nothing to do with wheel speed. If you were to put the plane on a treadmill, the wheels will spin under the airplane. Well, a small amount of friction between the wheels and the ground, as well as the wheels and the wheel-bearing will hold the plane on the treadmill, thus it will move backwards some (slower than the rate of the treadmill though)

OK so now you turn on the engines and the THRUST puches air thus the plane starts to move forward. For the plane to not be able to more forward, the friction between the wheels and wheel bearings would have to be so high that the thrust couldnt overcome it. The MAX amount of friction is absolute lock of the wheel bearings, this all the friction is between the tires and the treadmill. So your saying there is NO possible way a plane could even more forward if it had non-rotational rubber wheels? I agree that it wouldnt move very fast, but a jet would sure enough more forward at least slowly!

But we all know that the friction between the wheels and the plane isnt too much seeing as "stong man" competitions hold plane pulling contests. OK, so your saying the thrust of a jet at takeoff 70% of throttle is LESS than that of ONE human!? fucck off!

So what exactly is the friction percent of the plane and I am guessing the friction/drag of the wheels is going to increase as speed increases. But the extra 30% of thrust avaliable is WELL capable of overcomming this friction.

All thats really happening is the wheels are spinning twice the speed per unit of air speed. The plane is going to take off, the wheels are just working overtime.

YAY!

 

[IamDeMan 5,000+ posts]

basic rundown...
force = mass x accelerarion

in order for the plane to stand still (accel = 0) there has to be an equal and opposite force applied to the plane

the treadmill will apply a force to the wheels

the wheels will spin, and convert the force, via friction, to heat.

the planes motor will exert a force large enough to cause acceleration, thus the net forces applied to the plane are not 0

please show me where an equal and opposite force is being applied to the plane, such that the net forces on the plane are equal to 0...

They failed to tell you that my penis is chocking the wheels.

 

[req 5,000+ posts]

i have not read this whole post.

to this question;

If a plane is traveling at takeoff speed on a conveyor belt, and the belt is matching that speed in the opposite direction, can the plane take off?

the awnser is no. takeoff speed has to be over a hundred mph. if the runway is moving in the opposite direction @ 100mph, and the jet is thrusting so it shuold be at 100mph, it will remain relativly still.

you are all nuking this whole thought process. the wings need to be moving at take off speed. sure - the jet could possibly go into afterburners (if the one they use on the show has them) and overcome the belt, but that is not the question that has been asked.

a plane is traveling at takeoff speed...and the belt is matching that speed...can it take off

no.

/thread.

 

[Chevillac 5,000+ posts]

well see tonight, im done with arguing,

you cant even get that right, its tomorrow night. I guess this week must be on a treadmill, and we are stuck on tuesday.

 

[04_edge 10+ year member]

im not saying the plane cant take off from a treadmill, it can. but its going to take alot more power to get it to take off then normal...

 

[Chevillac 5,000+ posts]

i have not read this whole post.

to this question;

the awnser is no. takeoff speed has to be over a hundred mph. if the runway is moving in the opposite direction @ 100mph, and the jet is thrusting so it shuold be at 100mph, it will remain relativly still.

you are all nuking this whole thought process. the wings need to be moving at take off speed. sure - the jet could possibly go into afterburners (if the one they use on the show has them) and overcome the belt, but that is not the question that has been asked.

a plane is traveling at takeoff speed...and the belt is matching that speed...can it take off

no.

/thread.

but arent ground speed and air speed different? Planes go by air speed.

 

[hoss 5,000+ posts]

Exactly, but in order to gain air speed, you first have to increase the ground speed to take off. Im done trying to explain this, just watch the **** myth busters!! lol

you havent explained it, and dev, i think you worded it a bit awkwardly...

the wheels are moving at a rotational speed.

the plane is moving at a velocity (note, velocity is defined by having a speed, and direction)

increased rotational speed does not equal increased velocity. the airplane is able to increase velocity inproportionatly to the wheels rotational speed because of the way force is applied.

 

[04_edge 10+ year member]

you cant even get that right, its tomorrow night. I guess this week must be on a treadmill, and we are stuck on tuesday.

i thought today was wedensday

 

[IamDeMan 5,000+ posts]

i have not read this whole post.

to this question;

the awnser is no. takeoff speed has to be over a hundred mph. if the runway is moving in the opposite direction @ 100mph, and the jet is thrusting so it shuold be at 100mph, it will remain relativly still.

you are all nuking this whole thought process. the wings need to be moving at take off speed. sure - the jet could possibly go into afterburners (if the one they use on the show has them) and overcome the belt, but that is not the question that has been asked.

a plane is traveling at takeoff speed...and the belt is matching that speed...can it take off

no.

/thread.

Oy vey. air will be going over the wings because the plane would move forward at the same velocity. Hell make the treadmill doo 200 MPH and lane doo 100. The plane would still move forward. It's thrust isn't derived from pushing off the ground. It is derived from pushing off atmosphere! The wheels will just spin faster.

 

[DBfan187 5,000+ posts]

i thought today was wedensday

you thought wrong.
You fail.

 

[req 5,000+ posts]

this whole argument about more thrust after the fact is irrelavant.

the key word in the question was "MATCHES". if the belt MATCHES the jet, the jet will not be going forward. so stop arguing a null point. sure the jet most likely could overcome the belt. but thats not the question.

 

[04_edge 10+ year member]

but arent ground speed and air speed different? Planes go by air speed.

i dont know why this is so hard to understand.

they only air that will be moving is what the propeller is moving, but that is not the air creates the lift, its the air that travels under the wings that does it. there will be NO air traveling under the wings.

 

[hoss 5,000+ posts]

They failed to tell you that my penis is chocking the wheels.

shouldnt take much to get past that then //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

i have not read this whole post.

to this question;

the awnser is no. takeoff speed has to be over a hundred mph. if the runway is moving in the opposite direction @ 100mph, and the jet is thrusting so it shuold be at 100mph, it will remain relativly still.

you are all nuking this whole thought process. the wings need to be moving at take off speed. sure - the jet could possibly go into afterburners (if the one they use on the show has them) and overcome the belt, but that is not the question that has been asked.

a plane is traveling at takeoff speed...and the belt is matching that speed...can it take off

no.

/thread.

you should read the thread, we have destroyed this idea countless amounts of time, and it still comes up, and always starts with "i havent read all of this but...". and i know this to be a fact (look at page 7)

im not saying the plane cant take off from a treadmill, it can. but its going to take alot more power to get it to take off then normal...

no, its not going to take as much force as you think, the ONLY force being applied to the airplane itself, is friction.