Answer to the aeroplane problem on Facebook

The conveyor belt is moving in the opposite direction to the wheels, so the belt and wheels are moving at the same speed, but canceling each other out, so the plane is stationary, I think.
The conditions of this question are actually illogical I think. For example, what is powering the conveyor belt to move in the opposite direction to the wheels?
If the conveyor belt was started up, with the belt moving backwards, and then the wheels placed on the belt, the belt would spin the wheels forwards at the same speed as the belt was moving backwards.
Powering up the plane engines would normally move the plane forwards. But that would mean the plane would try to move off the belt. If the plane powered off the belt it would not be going fast enough to get wing uplift to take off, so the wheels would just run off the belt onto the ground.
Once it's off the belt it is out of the conditions of the question.
So, the plane can't take off directly from the belt unless the belt can run fast enough to get wing uplift. How fast would the plane need to go to get wing uplift? Let's say 100 kmh. Can a conveyor belt run at 100kmh? How long would the belt have to be - the length of the runway? Is that possible?

From the xkcd link a few pages earlier. Jet engines produce enough thrust to launch a dinosaur. The plane will take off no matter what.

I thought this one had been done to death. The plane's wheels have nothing to do with how fast it can go. They only allow it to move across the ground. The only impediment to the plain achieving take off speed is the rolling resistance of the the wheels, which I would have thought would be negligible.

Here's an alternative theory, the conveyor is moving so fast as to draw an airflow under the plane's wings to counteract the flow over the wings, thus no speed differential, thus no lower pressure above the wing, thus no lift.

Let’s just put the conveyor in reverse for fun.

jet engines don't produce thrust at all

they develop massive low pressure in front of the nacelle and the aeroplane...(its an aeroplane, not an aircraft)....moves into the low pressure...simples

bring it on....

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Originally Posted by ramblingboy42

jet engines don't produce thrust at all

they develop massive low pressure in front of the nacelle and the aeroplane...(its an aeroplane, not an aircraft)....moves into the low pressure...simples

bring it on....

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That might be a discussion between you and NASA. :lol2:

What is Thrust?

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Originally Posted by NASA

Attachment 139679

What is Thrust?

Thrust is the force which moves an aircraft through the air. Thrust is used to overcome the drag of an airplane, and to overcome the weight of a rocket. Thrust is generated by the engines of the aircraft through some kind of propulsion system.

Thrust is a mechanical force, so the propulsion system must be in physical contact with a working fluid to produce thrust. Thrust is generated most often through the reaction of accelerating a mass of gas. Since thrust is a force, it is a vector quantity having both a magnitude and a direction. The engine does work on the gas and accelerates the gas to the rear of the engine; the thrust is generated in the opposite direction from the accelerated gas. The magnitude of the thrust depends on the amount of gas that is accelerated and on the difference in velocity of the gas through the engine.
The physics involved in the generation of thrust is introduced in middle school and studied in some detail in high school and college. To accelerate the gas, we have to expend energy. The energy is generated as heat by the combustion of some fuel. The thrust equation describes how the acceleration of the gas produces a force. The type of propulsion system used on an aircraft may vary from airplane to airplane and each device produces thrust in a slightly different way. We will discuss four principal propulsion systems at this web site; the propeller, the turbine,or jet, engine, the ramjet, and the rocket.

Gas Turbine Propulsion

Thrust is the force which moves any aircraft through the air. Thrust is generated by the propulsion system of the aircraft. Different propulsion systems develop thrust in different ways, but all thrust is generated through some application of Newton's third law of motion. For every action there is an equal and opposite reaction. In any propulsion system, a working fluid is accelerated by the system and the reaction to this acceleration produces a force on the system. A general derivation of the thrust equation shows that the amount of thrust generated depends on the mass flow through the engine and the exit velocity of the gas.

During World War II, a new type of airplane engine was developed independently in Germany and in England. This engine was called a gas turbine engine. We sometimes call this engine a jet engine. Early gas turbine engines worked much like a rocket engine creating a hot exhaust gas which was passed through a nozzle to produce thrust. But unlike the rocket engine which must carry its oxygen for combustion, the turbine engine gets its oxygen from the surrounding air. A turbine engine does not work in outer space because there is no surrounding air. For a gas turbine engine, the accelerated gas, or working fluid, is the jet exhaust. Most of the mass of the jet exhaust comes from the surrounding atmosphere. Most modern, high speed passenger and military aircraft are powered by gas turbine engines. Because gas turbine engines are so important for modern life, we will be providing a lot of information about turbine engines and their operation.

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You might also notice that NASA have called the aeroplane above an aircraft. Here is an explanation of the differences but it is an aeroplane, an airplane and an aircraft.

What is the difference between an aircraft and an airplane? | How Things Fly

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Originally Posted by Smithsonian National Air and Space Museum

Q:What is the difference between an aircraft and an airplane?


A: An aircraft is any machine that can fly. Airplanes, hot air balloons, helicopters, or even flying platforms are considered aircraft! An airplane is a specific type of aircraft that has fixed wings and is heavier than air that is capable of sustained, powered, and controlled flight.

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Quote:

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Originally Posted by ramblingboy42

jet engines don't produce thrust at all

they develop massive low pressure in front of the nacelle and the aeroplane...(its an aeroplane, not an aircraft)....moves into the low pressure...simples

bring it on....

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Can we assume that you also subscribe to the theory that helicopters can't actually fly?

The theory is that they are so ugly that the earth repels them.

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Originally Posted by RANDLOVER

Here's an alternative theory, the conveyor is moving so fast as to draw an airflow under the plane's wings to counteract the flow over the wings, thus no speed differential, thus no lower pressure above the wing, thus no lift.

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The conveyor would have to go backwards to do that....

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Originally Posted by vnx205

Can we assume that you also subscribe to the theory that helicopters can't actually fly?

The theory is that they are so ugly that the earth repels them.

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Nah, it's the noise, Stupid, -Its the Noise! - so much of it bouncing between the rotor blades and earth... builds up pressure and pushes it UPwards.

Simple !

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