9/10 people get this wrong
A plane is standing on a large conveyor belt. The plane moves in one direction, while the conveyor moves in the opposite direction. This conveyor has a control system that tracks the plane speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction). Can the plane take off?
in this exact construction it won't be able to take off because there is no forward speed. I've seen the Mythbusters thing yesterday after the first thread and that plane definitely had forward speed and therefore lift.
If the speed was matched perfectly and the plane remained stationary (unlike that fucked mythbusters test) then the plane can not lift due to no wind flowing beneath the wings to make it lift.
Damn it, you are retarded! Of course it is moving forward!
"Aircraft propellers or airscrews convert rotary motion from piston engines, turboprops or electric motors to provide propulsive force."
You'll find that all airplanes take off at full power, and at full noise, the wash from the prop is enough to provide lift.
Also, the plane will accelerate off the belt regardless of the speed of the conveyor. The plane isn't limited by a gearbox to the wheels, But by air speed.
The wheels of the plane do nothing but keep it off the ground.
It uses the propeller to pull itself forward, the wheels could be spinning any speed any direction and the plane wouldn't care. The plane would pull itself off the conveyor belt in OP's image and probably break itself from the fall. If the conveyor belt was a mile long the plane could take off.
Air speed is what a plane requires to liftoff, due to the air passing over the wings generating lift. If the plane is moving on a conveyor belt, then it is moving in one direction while the conveyor moves in the opposite direction, however this does not mean that the air is not passing over the wings of the plane.
I think the reason people get this wrong is that they dont know that the wheels are not even connected to a motor. So there is nothing pulling it back, it wont stay on that treadmill for more than 3 seconds
in reality what will happen is the plane will move forward because the prop pushes it that way and the wheels will have no resistance to act upon it and the plane will fall off the conveyor belt
Why would the plane just sit there? If you were on a treadmill set up in the same way wearing roller skates, and you tried to pull yourself forward with a rope, what would happen?
i love how the sheet moved much faster than the plane creating a form of traction that sped the wheels up. In OP pic the device is able to match the speed causing no traction but a idle plane with spinning wheels.
Nothing about the wheels matters.
The only thing that matters is the speed of the aircraft in relation to the speed of the air around it. Totally disregard whatever is happening with the wheels.
This is now a Trol Physics thread.
Why wouldn't this work? If you just freeze it in it's near-boiling state then unfreezing it would covert it back to it's original state. Is it untrue because you can only use it once or...?
Let's use this analogy. Instead of looking at the airplane, let's back up and go into the airport. Suppose you're walking down to your gate
and pulling your carry-on bag behind you. It's a nice new bag with low friction wheels. No problem! Up ahead you see one of those moving
walkways. You don't see anyone coming, so you decide to do a little experiment. You go over to the walkway that is moving TOWARDS you and
place your bag on it. Meanwhile, you step off to the side of the walkway, and still holding on to the handle of your bag, you continue to walk along. In fact, you intentionally walk along at the same speed that the moving walkway is going, just in the opposite direction. Question: does the bag move or does it remain stationary as you keep walking? Obviously it moves with you. So why does your bag move forward when you are walking at the same speed of the conveyor going
in the opposite direction?
The answer to that question is also the answer to the airplane-conveyor question. To complete the analogy, the pull of your arm is analogous to the force of the airplane engines. The bag's
wheels are analogous to the airplane tires. Do the nice low-friction wheels on your bag on the conveyor pull against you anymore than they
do when you're just pulling your bag along normally? No, they don't. They are free-wheeling, after all. Meanwhile, you're pulling the bag
with the same force in both cases. So in both cases, the bag keeps moving forward. Likewise with the airplane, the pull of the engines
doesn't change nor does the force on the airplane imparted by the tires change no matter what the ground is doing underneath the tires.
You have the same force imbalance in either case, and since Force = mass x accceleration, you have the same acceleration. Remember, we are talking airplane engines which push against the AIR, not the ground. The acceleration is with respect to the AIR, thus the airplane develops a speed relative to the air and can eventually take off.
The magnet that pulls down one metallic ball pushes away the next ball. Do you know how a generator / motor works? It only works since the electromagnet turns on and off repeatedly.
It is an electromagnet that turns off repeatedly.
well first off the magnet wouldnt just pull only down, it would continue to pull the ball even as it passes, creating a force opposite of what you want. Second, generators have resistance to turn them, way more than the force of a ball filled with air in water, especially since the ball is resisting its own chain.
No, the liftoff platform still needs to be the same length. The airplane has to travel the same distance to reach the same airspeed to enable liftoff. The only thing different is that the conveyor belt is causing the wheels to move twice as fast as they normally do.
Even with a magic seal, the ball needs to displace its own volume in water at that depth in order to enter. The work that takes is equal to the work the ball can do as it floats back to the surface.
Well and if it's an electromagnet, you would need electricity. Therefore this machine is pointless, since you would turn electric energy into mechanical energy and then back into electric energy which the machine consumes again.
No it wouldn't work.
The car needs like 300CC of cracking power to start. the AAs wouldn't even produce more than 1 or 2 CCs.
Plus Car batteries recharge while you drive and those look like normal batteries to me.
Anyone who says yes is thick I have my ppl and it dosnt matter how fast the wheels move you need air resistance to create a vacume on top of the wing to create lift. If the plane stays in the same location it can't fly anywhere
Lift has nothing to do with a vacuum on the top of the wing.
It's the air under the wing that is directed downward, causing an equal and opposite push upward.
No, it can't.
The force that lifts up the plane is provided by the air passing the wings - see here: http://en.wikipedia.org/wiki/Lift_%28force%29
since the plane is not moving relative to the air, there is no force -> the plane can't take off
It depends on how long the conveyor belt is. The plane will move forward since it is the propellor and not the wheels that is causing it to move.
The wheels will spin doubly fast.
The plane will either take off of roll off the conveyor belt killing all aboard, depending on how long the belt is
Yo, retard, the plane is moving relative to the air because the propulsion isn't provided by the wheels but by the propellor, the propellor doesn't give a crap about the conveyor belt.
Do you people even think?
Its the air which is moving faster above the wings than beneath.
This causes an underpressure above the wings and the plane gets "sucked" up into the air at high enough speeds.
The prop is just there for creating the speed.
the amount of air moved by the propellor is far to small - just look at the size of an helicopter for comparison
Maybe if you stayed horizontal the whole time and were very careful not to break the surface tension, you might. But if you go just a little bit too vertical, you'll fall through.
>lubricated ball bearings
>clearly says prevents loss of water
>uses less energy than it produces
It just needs to be started.
Because the computers have to do what is known as a handshake with the other end, and if you have more than 1 receiving device then the handshake would never finish, so you'd get no connection at all...
this is retarded, you haven't addressed the one and only key aspect that relates to a planes ability to fly, its forward air speed, which translates to the amount of lift able to be generated by its wings. technically a plane can fly backwards if it is facing into a strong enough headwind and is able to maintain lift at low speeds, the Caribou is famous for this. if the convener belt matches the speed of the plane as it taxies then it is not generating any lift via forward air speed over the wings, which is what you need to make it fly.
It may eventually, but would have a harder time than if there was no turn table.
This is assuming the turn table is not on and assuming the rear propellor doesn't move faster than normal to compensate.
The propellors spin and the helo spins in the opposite direction but not as fast as it is heavy and has drag. So the propellors would have to reach a higher speed than normal before lift.
The helo would probably crash shortly after, having started its lift already in a spin.
lol, i remember drawing this a long time ago in response to a similar thread....
D'oh it just dawned on me that the conveyor belt could be moving at 10,000mph and the plane only at 50mph and the plane would move forward.
The wheels in a sense don't exist. They're just there to hold the plane up.
What the fuck are you talking about?
The propellor doesn't have to move the fucking air, it has to move the fucking plane, you know, the thing it was designed for.
Let me explain this to you again, THE CONVEYOR BELT DOESN'T MATTER BECAUSE PLANES DON'T MOVE USING THEIR WHEELS!
That being said, if the plane was moving backwards on the conveyor belt at 100mph and the plane started the engine and then set off to reach 50mph.
Wouldn't it then just stay stationary?
Relativity. Plane needs relative air velocity. Not a fucking dumb as fuck inproportionate god damn conveyor belt. And besides, I don't know what conveyor belts you've been looking at but they aren't that fucking big. And if they were, they'd probably be for transporting your mom to McDonald's and back... for fucks sake. > tfw I'm right
No, it would have no effect on that. It doesn't matter how fast the blades are spinning relative to the body of the helicopter. The only thing that matters is the speed of the blades through the air.
The fan is blowing air out at the plane at the same speed the plane is travelling
who cares - it is clearly statet in ops post that the belt moves so fast that the plane remains at the same spot the whole time
this was not true in the mythbusters experiment, that's why the plane was able to take off
plane not moving -> air not moving under the wings -> plane does not take off
That's because my feet are pushing against the ground. but a jet engine pushes against the air. If I attach a jet engine to my body on a treadmill and set them both for 100 mph that jet engine is gonna blast me forward past the treadmill no matter what. This whole question is to see if you understand how thrust works.
The Hypothesis are clear, the plane "moves" in one direction and the conveyor moves in the opposite at the same speed, it means that the plane "fucking moves" at 300km/h and the conveyor moves at the opposite direction at 300km/h. The plane "is moving" for the hypothesis so dont tell me that it's not moving. If the plane speed is 0km/h then the conveyor speed would be 0km/h
I really don't want to accept that this one won't work. But, it won't work.
You push the stick, but you're only pushing the collection of molecules at your end of the stick. They move, and they move the molecules ahead of them, which move the molecules ahead of them, and so forth. It would actually take much longer than a year for the movement to reach the opposite end of the stick.
I know. I don't like that, either.
you don't understand what i'm saying, do you?
The wheels will match the speed off the conveyor belt as long as the propellers are at the minimum required speed for the plane to move since they don't have engines in them. The thing that makes the plane go forward is the propeller pushing air backwards. It might be 4-6% harder for the plane to take off but as long as the wheels don't explode it will be just fine.
Tthe belt cant hold the plane in one spot.
The question is flawed.
They completely fucked up and they refuse to admit it.
The conveyer they used did not match thr speed of the plane, only forced the wheels on the plane to spin twice as fast. If the plane were completely stationary there would be 0 wind speed and 0 lift.
ah, now i understand the concept - i sort of had it in my head that the plane would stand still! took a while...
pic slightly related...
The wheels don't generate lift, you fucking imbicile. Wind needs to travel past the wings in order to generate lift. The plane will never take off unless there's a strong as fuck headwind flying direct at the nose of the plane.
Fuck you underaged retarded disgraces of humanity.
No there isn't. It's hard to imagine, because the stick feels like a ridged single piece of matter, but it's not, it is made up of particles. Moving the the particles in one end of the stick pushes forward the ones throughout the stick which i turn push others forward.
While this seams instantaneous, it isn't.
seems i had trouble with the original setup...
pic somewhat related...
Assuming the propeller is actually spinning, the plane would move forwards and probably fall off the end of the treadmill. Given a strong enough propeller and a longer treadmill, the place would be able to take off.
If the propeller wasn't spinning however, the plane would remain stationary and not go anywhere.
This is all assuming the planes wheel bearings are frictionless as well.
How about this one btards..
Big platform (sheet metal) is laid on ground and a helicopter is placed on top and bolted to the sheet metal. Assuming platform is wider than wingspan, and platform is only attatched to the helicopter, can helicopter lift off?
If the propeller isn't spinning the plane would fall off the back of the conveyor belt.
even if the wheel bearings are frictionless the wheels aren't and they have around 1100 kg pushing down on them in total.
Yes, but it would have to displace enough air to lift that plate. It would be very difficult. But an infinitely powerful helicopter could do it.
I would doubt that a helicopter ever actually made could do it.
i do my phd in experimental quantumoptics =)
sometimes this stuff makes you blind for obvious/easy solutions
Answer is no. In order for a plane to take off it needs thrust, and lift. If the plane is standing on a conveyor belt, going one direction whilst the belt is going the other direction nearly at the same speed. It might as well be standing still. No lift generated from the speed. It might get thrust, but not sufficient enough for flight.
No. Any air dispersed downwards would create force equal and opposite to the force of the bolts locking down the helo. Rest of air is moving perp to the ground ie no lifting forces.
no, i'm an experimentalist - usually i'm the one to make fun of them for not understanding how stuff works in real life ... that adds to my shame ;)
If the ground is flat, yes. If, though, there was any way for some air to sneak in under the plate, and if the rotor was powerful enough, and if the whole thing wouldn't tear itself to pieces...It would only take a little air getting under to start it.
But, yeah, if it was a flat plate on a flat surface...I guess not.
the answer is "yes" IF you pray and you believe that Jesus died for your sins and rose up to the Heavens after he was crucified and died, and now sits at the right hand of Yahweh, the Father.
Because everything in the Bible is true and with enough faith you can accomplish anything.
> faith > science
The friction is the only thing to argue one way or the other.
IT takes of if...
It doesn't take off if...
If it is a radio controlled plane with good bearings then yes it flys. If it is an actual manned aircraft weighing 3,000 pounds of more, then friction may cause a problem.
Here's the answer. The question doesn't work.
The speed of the wheels to the plane has nothing to do with the flight of the plane. Lift is created by the wings. For the plane to take off the wings have to have air flowing over them. If the plane was not moving forward or backward relative to the ground and air that the conveyor belt is sitting on, but the wheels and conveyor belt were moving at any speed, the plane would not take off. If that same situation was true and the plane was moving forward with enough speed to create sufficient lift the plane would take off. The conveyor belt could be moving forwards making the plane's wheels spin backwards, but if the planes velocity relative to the wind around it is still great enough it will take off.
The question is flawed and needs to be elaborated upon. In it's current form, there is no answer.
Can someone explain how the plane will fly?
So the thrust generates enough force for the plane to take off? But I thought the lift comes from the flow of air...
Sorry neuroscience undergrad here
ah, you know how it is ... you hear basic courses in every subject, so usually you have a nice grasp about things - makes you prone to oversee things, though