Myth is True( Not busted) Conc. Violate fluid mechanics

1. Lift is independent of wheels, engines, jets and propellors etc. It is only depenent on the lift coefficent, fluid density and relative velocity of object(wing) and fluid (air). Examples include wind tunnels (air moving past stationary wing develops lift) and airplanes landing into the wind (landing speed is decreased while relative velocity between air and wing remains same, so lift remains same). In short wing with zero relative velocity between wing and air produces 0 lift.

2. Speed was measured in different frames, truck speed was measured against pavement while plane speed was measured against air. In short if take of speed was 25 mph, speed of the truck was 25 mph, the plane would only measure 25 mph if it was moving 25 mph relative to the air i.e. 50 mph relative to the conveyor (this could be shown if speedometer was installed on plane wheel). If the plane and truck were going the same speed to an outside observer, the plane would remain stationary (i.e. radar gun would measure plane speed of 0), but it didn’t it moved away from the camera.

3. It should be noted that friction, means of propulsion have nothing to do with it. One could strap wings to a car and measure the cars velocity and corresponding lift produced by the wing. If the test on the conveyor were replicated with the car and wing rig, one would see that to achieve the same amount of lift as the first test, the car would be going twice as fast (according to the spedo) ( i.e. a person sitting in the car would not see the world around sitting still but moving by at half the speed recorded by the cars spedometer

In short the plane will ONLY take off from a conveyor when the relative velocity between the wing and air is that of the measured take off speed.

Therefore the plane will take off when its speed relative to the conveyor = takeoff speed+ truck speed. NOT the speed of the conveyor

watch them explain it again. http://youtube.com/watch?v=KSBFQOfas60

Tape a handheld GPS to the belt on the treadmill, tape a handheld gps on the plane.
have them both going the same speed in opposite directions.
The plane will move forward and fly.
The planes GPS will show the same speed needed to take off everytime, doesn’t matter if a treadmill is under it or not.
You could have the conveyor belt doing 10 times the speed of the plane, it doesn’t matter. They are not connected.

Since the caveman invention of the wheel, its only purpose was to eliminate friction between the ground and the object sitting on the wheel.

Its not that hard.

The only thing that made the plane take off was the thrust of the propeller moving the plane forward which would then have laminar flow of air over the wings.

One way to completely put this myth to rest and be busted is to place a glider on the treadmill. Tie a rope to the nose to stop it from moving backward and start up the treadmill. It wouldn’t move in a vertical direction one iota no matter how fast the treadmill went. QED.
I’d like to see what the Mythbusters have to say in response to all of us who have shot down their findings.

The MYTH is can a Converyor Belt, keep an airplane stationary. Answer NO it Can’t !!
FACT. You cannot stop a planes forward motion with a conveyorbelt.

Think of it as more of a riddle.

Here is another for you. If a car is going 100mph west but the wind is blowing 100mph east, is the car still moving.
Yes, of course it is. You can’t really stop a car with wind, thats not where its propulsion comes from.

Its the same question as the plane, just reversed.

Its not that complicated guys.

I know Jamie said that there was heated discussion on this, however given my very basic knowledge of flight principles, I am certain that a propellor alone is not capable of providing sufficient airspeed over a wing to produce sufficient lift without the addition of forward motion over the wings to supplement the thrust developed by the propellor. Looking at a Helicoptor which is a rotary wing design, they require the blades to be turning at a significant rate before lift is generated, thrust from a plane is developed in the same way but lift is only provided by the differential pressures of air over the wing, the whole length too I might add as the rate of lift produced by a wing varies along its length depending on thickness (camber) and the chord (the distance from leading to trailing edge). Other factors like Aspect Ratio and the whole Co-Efficient of Lift will also play a role in determinig the optimum conditions for flight, height above sea level, air pressure and density as well as humidity and temperature.

Good luck to all in relation to this myth, I know where I stand in relation to these results and it will be a very good experiment that would cause me to change my mind.

David,

If you consider all of the forces on the plane, you’ll know why it had to fly. I’ll oversimplify to save time and confusion for those who don’t have a physics background.

1) The vertical forces start out as the weight of the plane downward and the force of the earth upward. Those cancel out so the plane stays on the ground. We also have a very slight, and insignificant, amount of lift created by the slipstream from the propeller over the wings, which creates a trivial amount of vertical lift (not enough to do anything, so it can be ignored).

2) Horizontally, we have the treadmill pulling backwards with the friction of the wheels opposing that. We also have the forward force generated by the propellers (too complicated to explain here how that works), opposed by the friction of the wheels. Let’s ignore air resistance for simplicity’s sake since it doesn’t play a significant role.

3)The key point is that, once the torque (rotational force) on the wheels is great enough, they will start to spin and the friction will become essentially irrelevant. That torque is created by the force from the treadmill plus the force from the propeller transmitted through the body of the plane. They both act in the same direction on the wheels, causing them to spin. Once the wheels start spinning, the backwards force acting on the plane from the treadmill will be so small relative to the forward force from the propeller that the plane will start to move forward. THIS IS THE KEY POINT!!! The fact that the wheels will spin at twice the rate as during a “normal” takeoff is essentially irrelevant.

4) Once the plane starts moving forward relative to the earth (and air), it will take off as if the treadmill were not there, following the usual laws of physics whereby the vertical lift is generated by the flow of the air over the wing (not so much from the propeller as from the forward movement of the plane through the air).

If that causes your head to spin, just think of it this way: All the treadmill does is cause the wheels to spin faster; it doesn’t move the plane backwards once the propeller starts moving it forwards.

Answer….. it flys. The conveyor belt is simply matching the speed of the plane, not stopping forward motion.
If the plane was stationary, the conveyorbelt would never move in the first place because it has no “speed” for the conveyor to “match” in the first place.

1. everyone knows a stationary plane can’t fly. No myth or argument about it.
2. Everyone SHOULD know, that a conveyorbelt can’t stop a plane because the means of propulsion are not related.

The conflict
1. “no flys”, thought the “will flys” were expecting it to just rise up like a harrier magically because the wheels were spinning.
Obviously the “no flys” thought the “will flys” were morons.
But the “no flys” just misunderstood the question.

2. many “no flys” are still convinced that a conveyorbelt spinning in the opposite direction can affect the forward movement of the plane.

If you have hours of spare time to kill, go to the mythbusters forum. They are on about 90+ pages since the show still arguing.