Printable View
Don't yell at me. This example is all about Newton's third law. AS long as the wheels of the plane are turning faster than the treadmill, it will take off. When the two numbers match, it will not move forward. Get over it. Planes use air to grab a hold of, cars use the road. Two completely different scenarios. One does not equivocate to the other.Quote:
Originally Posted by gn7
THRUST is going to move the plane foward (either jet or SCREWING ITSELF through the air)... I'm just trying to find out how fast you have the plane going backwards on the pretend treadmill... I wanna know how long (not IF but WHEN) it will take me to lift off as soon as I start making thrust, without any thrust the wheels are glued to the treadmill belt just like the aero-plane is and she is going backwards...Quote:
Originally Posted by Tishimself
Let's say for the sake of argument, that the engines on a jet propel it forward at 800 miles per hour (I have no idea how fast they really go, but bear with me here). Now imagine that the plane is sitting on a really long conveyor belt. Both the belt and the plane are stationary, and the jet engines are off. Now, imagine that the conveyor belt starts moving at 800 mph. Seeing that the plane's engines are off, the plane gets dragged backward at 800 mph by the belt.Quote:
Originally Posted by 2manymustangs
Now, if the pilot fires up those engines, that 800 mph of force is only going to counteract the backwards-moving conveyor belt, right? 800 mph in one direction less 800 mph in the other direction equals 0 mph. So, the plane sits stationary as the conveyor belt goes by beneath it.
If the plane isn't moving, then the air isn't moving above and beneath the wing at the required 800 mph, thus creating no lift. And that's that.
This was a great thread! It was my favorite next to "GOD IS FAKE"
It will take a fraction of the TOTAL thrust to stop the plane from moving backward and start moving forward... Do I have one mile? How long is your "really long conveyor belt"???Quote:
Originally Posted by Tishimself
At 800 MPH backward I don't have very long before I'm in the abyss...
Tish, I said I was done, but now I really am. Read this. And stop trying to twist this into something you think is plausible.
http://www.airplaneonatreadmill.com/
Make sure you read the whole thing.
There are just as many peeps out there saying it will work as there are saying it wont. Don't have time to read, it, most likely I already have when I researched this subject way back when...LOL.... ;)Quote:
Originally Posted by WESTERNAERO
You are too funny. First it was converted thrust to the wheels in one post, now its AIR verses Surface. Your screwing yourself with you own posts. Its too funny. You know what you want to say, because you see it in you head, but you can make sense of it in words.Quote:
Originally Posted by Tishimself
Like I said, its a hypothetical brain teaser that doesn't allow the plane to move forward on the hypothetical tread mill. None of which has anything to do with REAL physics.
It never stated the length of it.Quote:
Originally Posted by 2manymustangs
Lets say that the conveyor is an infinite length... Is it a hard surface or squishy like grass/dirt AND are the wheels on the aero-plane rigid or soft/pneumatic???Quote:
Originally Posted by Tishimself
DO you dispute that the thrust will in short order overcome the rolling resistance (once you start spinning up the jet) and will cause enough thrust to stop the backward motion of the airplane?
It has everything to do with physics. Again, Newton's third law. Now , that said, I said in the beginning that the wheels transmit thrust through the landing gear to the wheelsets. You said no that's not it, it's the engines. So I came back and said it was the engines pulling air through them, they do not interact with the road in the same ways that a car does. Now I am contradicting myself. Not really. You keep thinking this has to do with the engines, I keep saying the engines are nothing without the wheels....LOL...you see? It's an endless pointless argument, but great fun to argue, because under the right circumstances, both sides are right. I owe you a beer...and you owe me one right back...... ;)Quote:
Originally Posted by gn7
BUMP... Tishimself... CMon...Quote:
Originally Posted by 2manymustangs
There are two factors at play here with this mind game, and Tish will twist them to fit his theory regardless, but in reality, he is trapped.
There can be two different types of treadmills. Motorized, or free moving. It matters not which we use here. So we will take on both, but the RULES apply to BOTH!
Free wheeling:
We have to assume an absolutely frictionless free wheeling treadmill. A man, dog, horse, bicycle, or top fuel dragster cannot move forward, Its impossible. At the same time, the treadmill will not move if they don't try to move forward. Its the attempt to move that moves the surface. None of them will fall off the tread mill, they just can't move. If a very stiff wind comes along, it can blow them right off the treadmill.
The plane does not need the surface to move forward. It can move forward and never have the treadmill move, except possibly in the same direction the plane is going because the tires drag it along. So now the treadmill, if moving, is going forward in the same direction. If it remains still, the plane moves. if it moves forward, the plane moves. But the plane CANNOT move the treadmill backward because there is no backward force to make it move that direction. The wheel are being dragged by the plane, and POSSIBLY the treadmill as well. The plane is not pushing off the tires, or the treadmill.
Motorized treadmill:
Tish, in his theoretical mind game, wants us to believe the plane has to rev the engine to stay on the tread mill or fall off. No different than any other motorized treadmill. EXCEPT, people, dogs, horses, and top fuel dragsters have 100% fricition that makes them need to "move" to stay on the mill. Stand there, and off you go.
However, our hypothetical plane, gets the same 100% frictionless bearing that were in the above freewheeling treadmill. If the treadmill moves, the plane stays, because it FREEWHEELS just like the above treadmill. However, because there ZERO friction between the plane and the tread mill, it is free to move forward, and as was stated before, the wheels simply double the speed of the surface until the plane takes off. But it can take off.
You can't have it both ways Tish. This is bench racing, remember.
So T, the earth rotates at approx. 1040MPH, making it the world's largest and fastest treadmill.
How is it that I can go 100 in my boat??
LOL :D
Boeing uses the earths rotation with SEA LAUNCH, they deploy commercial payloads via rocket at the earths equator to get a more accurate/TRUE launch and take advantage of the extra force at the equator versus 30-40 degrees north...Quote:
Originally Posted by Hotboat
SEA LAUNCH hangs out near the Queen Mary in Long Beach and is a big freaking mobile rocket launcher that gets towed around the ocean...
:hilarious: :hilarious: :hilarious:Quote:
Originally Posted by Hotboat
Saint Dave of Santo Diago pipe that little package of sunshine up your ass?
You crack me up sir :DQuote:
Originally Posted by gn7
What you are missing here is the wind speed. There is a huge headwind that is helping the plane take off. Listen to how loud the wind noise is. In fact you could argue that the treadmill would create enough wind at high speeds to do exactly what this plane is doing in this video.Quote:
Originally Posted by Tishimself
Just like before the responses to this thread truelly baffles me.
I think you actually believe it will fly and you are just stirring the pot.
MP
I wish that were the case, but I don't think so. I am certain he thinks it won'tQuote:
Originally Posted by Cat & Mice
There was a thread on another site years ago, and I just revisited the thread to remind myself what was said and believed. It was pretty funny, and sad at the same time. Only one guy, the guy that started the thread of course, refused to budge. Others were truly interested and learning.
Upside, it was a real case scenario, and the OP learned real quick once he got into the ACTUAL as opposed to the theory in his mind. I believe he still does not get the physics of it, he just can no longer argue his theory.
:hilarious:
Oh, oh wow. LOL. That was mind boggling, to say the least. I'll have whatever he's having. LOL. The treadmill is a non issue. All it needs to do is be large enough and long enough and fast enough to fulfill the requirements of the question. The friction is between the wheels of the plane and the surface of the treadmill. If anything, you need bearings on all those wheels that can withstand the stress. Again, all you need to know is this. It's all about the speed of the wheels. period. YOu get caught up in all the other BS and that's your downfall. The wheels transmit the thrust into movement. as long as the treadmill is moving in the OPPOSITE direction the plane is traveling, and the treadmill and wheels are moving at the same speed but in opposite directions, the plane will not move. Deal with it. YOu have overthought this way too far. It's actually very simple.Quote:
Originally Posted by gn7
With one caveat. the original question ONLY posed the problem using a 747. There are other types of planes that will fly. The 747 and other types of aircraft will not.