Will the Airplane Fly??????????

[nugundam93]

i'm afraid i have to change my position regarding this topic..there is no way the plane is going to fly.

becoz...there's no pilot...there was no mention of a pilot in the original question...not even a turning on of the engine.

joke lang peeps..to lighten up your day.

ding! ding! ding!

doc otep, panalo na ba? hehehe.

[Alpha_One]

ding! ding! ding!

doc otep, panalo na ba? hehehe.

Baka naman UAV yung eroplano...
...the plot thickens!

[nugundam93]

Baka naman UAV yung eroplano...
...the plot thickens!

aha! ongano...

[leolop]

di ako engineer, pero i think the plane will fly because forward thrust is dependent on the engines whether propeller or jet acting against the air, and not on the wheels pushing against the ground.

here is the best analogy i saw on the net to explain:

A thought experiment commonly cited in discussions of this question is to imagine you're standing on a health-club treadmill in rollerblades while holding a rope attached to the wall in front of you. The treadmill starts; simultaneously you begin to haul in the rope. Although you'll have to overcome some initial friction tugging you backward, in short order you'll be able to pull yourself forward easily.

[niky]

one thing more for all of you to analyze. an F1 car aerodynamics works just like wings but acting on oppsite direction, meaning pushing it down to the ground instead of lifting it up. the higher the speed of the car the stronger is the push downwards. put the car in a dyno or the same conveyor if you want. do you think it can create the downward force, no because there is no wind acting on it. even if you add in a jet engine behind, there will still be no downward force.

Hehe... just shot yourself in the foot.

An F1 car on a dyno is a car on an infinite treadmill. The dyno is basically a treadmill that keeps the car in place.

Rev the engine, the dyno will show you how much power it is exerting to keep the car from moving. Correct? Because the dyno/treadmill keeps the wheels in place, no matter how fast they turn.

Now, put a jet-engined car on the dyno. Try to dyno it. The dyno will show no power at the wheels because the jet engine doesn't power the wheels!

The jet engine car will then proceed to rip through the flimsy nylon straps (the same straps that keep 1000 hp Skylines in place) and drive straight through the garage wall.

Get it, yet?

[GasJunkie]

But crashing is different from flying though.

[Alpha_One]

Wait.. plane, dyno, nylon, garage?

I think steel cables and a hangar would be more appropirate... not sure if I'll get any dyno readings either though.

[Helios]

what mystifies me is how you folks can type so darn fast?

and who annoyed me was the person who's stupid enough to have left that conveyor belt on the runway!

[Chip]

I have stayed away from this thread, aside from posting lighthearted comments.

BUT last night while lying awake in bed, I actually started to give this serious thought.

The plane will not fly. Lift is created by air moving over the airplane's wings correct? Now there are 2 ways to move air over a surface:
1. Accelerate the surface through the air
2. Accelerate the air over the surface

Let us examine the first one. Accelerating the aircraft wing through the air. Since speed = distance/time and the airplane is held in place, no distance is covered, hence no speed. No surface is accelerated through the air. No lift.

Now for accelerating air over the wing. Even with the jet engines powering at full throttle(or whatever may pass for it in avionics), the air they suck -thereby accelerating it over the surface of the wing will not be enough to produce lit. And if ever they even succeed in sucking in enough air fast enough, it will not be distributed over the whole wing=no lift.

Think of an aircraft carrier. They have steam powered cataputs to accelerate the aircraft over a short runway to acheive lift in what otherwise would be impossible situations. If the treadmill thing worked, then aircraft carriers would have these instead of catapults to slingshot their planes airborne.

IT WILL NOT FLY

[nerbyoso]

sorry for breaking my word but i just cannot help it...sir, can you stop a car by aiming an electric fan into it? of course not..much like you cannot stop a plane by moving the runway under it...i dont think i can explain it simplier than that anymore...surrender na ako.

i just cannot see why a plane that can normally take-off with it wheels rolling at 20kph cannot take-off with its wheels rolling at 40kph (i.e. the tarmac moving the opposite direction at the same speed) while maintaining its take-off speed.

The prop/jet pushes the plane through the AIR until it reaches take-off speed, which is the same no matter how fast the wheels are going. again it uses the air to move forward and not the ground....in contrast to a car that uses the GROUND to move forward.

re: aircraft carrier...sir, i'm sorry, but i didnt get your idea regarding the use of treadmill/conveyor on an aircraft carrier...wala akong nakitang use/role for it to launch a plane..

ine-exclude natin yung VTOL planes dito sa usapan just to make it simple and not too complicated for others... but the way i see it the mere existence of such a plane (vertical take-off and landing) demontrates once enough thrust is created what happens to the ground is irrelevant...and thrust is not dependent on the planes wheels but in its engine/s that uses the air to propel it forward.

a conventional plane is no different than a VTOL except that it is designed to use a certain lenght of runway to achieve flight.

give it another serious thinking tonight.

[Negus]

IT WILL FLY!

the conveyor cannot stop the forward movement of the airplane. kumakagat sa hangin yung engine. aabante yan, yung gulong parang free wheel lang. pag umabante, magkakaroon na ng bernoulli effect or kung anuman iyon sa wings. kailangan lang mahaba yung conveyor para makaabot sa take off speed. kung maikli mag-crash yan ano magagawa nung gulong, hindi naman yun ang nagpapaabante ng eroplano..

[Chip]

The prop/jet pushes the plane through the AIR until it reaches take-off speed, which is the same no matter how fast the wheels are going. again it uses the air to move forward and not the ground....in contrast to a car that uses the GROUND to move forward.

re: aircraft carrier...sir, i'm sorry, but i didnt get your idea regarding the use of treadmill/conveyor on an aircraft carrier...wala akong nakitang use/role for it to launch a plane..


a conventional plane is no different than a VTOL except that it is designed to use a certain lenght of runway to achieve flight.

give it another serious thinking tonight.

I agree, you have to push the plane using air for it to reach a certain speed. Ang assumption ko dito is since the treadmill matches the wheel speed, the airplane never moves. No forward movement=no distance covered. No distance covered, no speed. No speed=no lift.

For example, when running at 5mph on a treadmill, does air flow over us at 5mph? No because we are stationary. Now for example we put on a rocket pack (ala Wiley Coyote) on our backs and use it to propel us 5mph(on roller blades) on a treadmill running at exactly 5mph. Will there be movement? Still no. It doesnt matter where the source of propulsion is (this case rocket pack), since the treadmill will always match our forward velocity, there can be no speed.

Kaya nga aircraft carriers and airports have certain runway lengths, that length is the minimum distance needed by the plane to acheive sufficient velocity to produce lift. Since running on the treadmill does not produce any velocity, no lift.

Ayoko nang pag-isipan to mamaya

[StraightSix]

Ang daming ayaw maniwala, hehehe.

Some people are concentrating too much on the wheel/conveyor belt-effect, that the basics get overlooked ... that the medium is air. The plane will move forward, even if you take out the wings. Just like what people on the other side of the argument keep pointing out, the wheels will just spin faster.

[kinyo]

Ang assumption ko dito is since the treadmill matches the wheel speed, the airplane never moves.

No. The plane will move because there is no friction between the plane and the treadmill, thanks to wheel bearings.

Now for example we put on a rocket pack (ala Wiley Coyote) on our backs and use it to propel us 5mph(on roller blades) on a treadmill running at exactly 5mph. Will there be movement? Still no.

Yes there will be movement because the roller blades effectively rendered the treadmill to be frictionless.

For example. You are on roller blades, standing on a very long treadmill. With treadmill not running, somebody pushes you forward momentarily and off you go rolling at constant speed. You will remain at the same speed forever if not stopped by very little friction force on the roller's bearings. Now while you are cruising at the same speed, the treadmill was started and moved backwards. Will you be slowing down now? No, because there is practically no friction between you and the treadmill surface. You simply continue to cruise at the same speed, but now the wheels are turning faster (because there is friction between the treadmill and the roller rubbers).

It doesnt matter where the source of propulsion is (this case rocket pack), since the treadmill will always match our forward velocity, there can be no speed.

It does matter where the propulsion is applied to a wheel. For a plane, propulsion is applied at the center of the wheel, similar to the roller blades, and wheel bearings effectively cancels out friction at the rubber surface. In this case, the plane (or the roller skater with jetpack) will move as usual, regardless of runway (or treadmill) movement.

For a car, propulsion is derived from friction between tire and road,i.e., propulsion is apllied at the bottom surface of the wheel. In this case, the basic intuition works. The car will remain stationary if the road matches the car speed. The car can be made to go forward or backwards depending on the difference of speed between wheel and road.

Kaya nga aircraft carriers and airports have certain runway lengths, that length is the minimum distance needed by the plane to acheive sufficient velocity to produce lift. Since running on the treadmill does not produce any velocity, no lift.

Ayoko nang pag-isipan to mamaya

With or without runway movement, the plane will move and take-off as usual requiring the same length of runway as usual.