# Tag Info

## New answers tagged aircraft

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The short answer is that the hypotheses assumed for the Bernoulli equation are not met for airplanes. (I can't speak for birds since I haven't studied that in detail.) In particular, The air is not incompressible and Energy is not constant - the plane's engines are adding energy to the airflow That said, it's "close enough for the engineers" - ...

2

It all depends on the conditions. The mass of the plane, the velocity, the silk strain, the breaking stress etc. play a role. By taking very large webs in order of 1km diameter you might end up with such results. Taking larger masses and webs in order of the wingspan would give you values of many meters thickness.

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I'm late to the party here and I think the top vote-getters (Skliwiz, niboz) have adequately answered it, but I'll give my two cents anyway: There are several ways to explain how an airplane flies. Some are more detailed than others, and unfortunately most popular explanation get it wrong. Here are some explanations that are useful, depending on the ...

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Sometimes you will see statements like 'some of the lift is caused by Bernoulli's principle and some of it is caused by Newton's laws", but this is the wrong way to think about it. The fact is that 100% of the lift can be explained by Newton's laws and 100% can be explained by Bernoulli's equation. Both approaches explain 100% of the lift. The problem is ...

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I think this formula would work better F=MxA Since you are hovering you need to consider the acceleration of gravity in your calculations. So you would get F= M x 9.832 meters per second squared. Use kilograms for the mass in this case

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There is a confusion of what that $v$ means. You are thinking about the velocity of the drone, which is stationary this $v_{drone}=0$. But in your equation, to calculate the power needed by the wings, you have to consider the velocity of the motor providing the thrust (propelling air downwards at a certain rate) to keep the drone floating which is making ...

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Power equals work/time. Work is force times distance, so you can simplify to force times speed, when the force is constant and the force is causing the speed. In your situation there is a force due to gravity that would do work on your drone, and what you need is for the drone to do work to counter balance that. In other words, power is always work over ...

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The problem is that finite wings inherently induce drag (called lift induced drag). Even if you could assume the wing infinite you still have parasitic drag. So you will always need to supply energy to keep the plane flying at a constant speed (and as a consequence to keep generating lift). Without drag it could, in principle, keep flying without power. It's ...

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In principle, you are right that it is possible to keep an object in the air without expending any energy. Think about a blimp, you can fill it with helium, and then just let it float. It doesn't have to do anything to float, it just floats because it is lighter than air at ground level (the air gets less dense as you go up). You can even make heavier than ...

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