Video #3: The Lift Formula

Video #3: Talking about the lift formula and how we can use it to understand how aircraft fly.

Script (with weird spellings and lots of comma’s to make the helpful American gentleman narrator speak properly!)

Welcome back! Episode 3 of the profpilot dot co dot ewe kay flight training video series, continues from episode 2, as is suggested by the name. Now you know how an aircraft flies, you need to know how it controls itself. In order to do that, we need to look at lift in more detail.

So, before we begin, I would like to issue a maths warning. There is an upcoming formula. Please brace yourself.

Drum roll Please.

This, is the lift formula. I will now explain it to you, and will keep it simple, so please, do not be alarmed, and more importantly, do not weep. The tears will only cloud your vision.

We could also write the formula like this, half, multiplied by d, multiplied by v squared, multiplied by s, multiplied by CL. But writing it this way, saves space, and makes it look more sciencey.

This, L, stands for lift. It is what we are trying to find out.

This, d, stands for the density of the air. Here is a picture of high density air, and here, is lower density air around an aerofoil. As a wing passes through high density air, more air particles will pass over it. If there is more air passing over the wing, then more lift will be created. Wings passing through lower density air will have less air particles passing over them, so there will be less lift created. We are still travelling at the same speed, but because there are less air particles around the wing, they pass over the aerofoil less frequently.

This, v, stands for the velocity of the aircraft. Here, you can see we are travelling quickly, and lots of air particles are travelling over the wing in one second. Just as before, more air particles passing over a wing means more lift is created. When we go slower, as we are here, less particles are travelling over the wing, meaning less lift is generated. This is why aircraft have to run down the runway quickly to get lift, and can’t take off while the passengers are still boarding.

This, S, stands for the area of the wing. Here is a small wing, and some blue circles to represent air particles again. As you can see, it cannot hold as many air particles as this large wing. The larger the wing, the more lift it will produce. Yet again, more air particles passing over the wing means more lift.

this, CL, stands for Coefficient of Lift, which varies depending on what shape the wing is, and also the angle of attack.

The easiest way to control an aircraft is by altering the angle of attack at the various primary control surfaces. Next episode, we will be looking at what angle of attack is, and how it is used to control the aircraft.

In the meantime, if you have any questions regarding this video, any of the other videos, or flight training in general, go to dot ewe kay and post in our forum! You will also find flight school listings, and reviews, so hopefully it will help you.

Thanks! Same again next week? Oh Joy.

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