Day 17

Test Tomorrow. I'm not all that concerned about it.  Basic aerodynamics and some simple physics. Should be pretty simple.

I learned something neat yesterday.

I had always wondered what the purpose of winglets are.

Winglets are the small vertical protrusions on the wingtips of some aircraft.

Those are winglets.

I had always imagined that they had some sort of function for aerodynamics or control, but I never knew what they really did.

Well, now I know.

As an airfoil (in this case a wing) goes through the air the pressure differential created is what produces lift. Since air wants to reach equilibrium and functions like a fluid, the low pressure air at the tips of the wings are prone to basically slip off of the ends of the wing to the high pressure side. When they do this, any potential lift is destroyed.

Winglets come very close to eliminating this phenomenon by creating a buffer between the low and high pressure sides which is more difficult for the air to overcome by moving along the lateral axis of the plane (the way it does without winglets).

While winglets are an obvious source of drag, the lift they help produce (or maintain, as it were) compensates for any added weight or induced drag.

Winglets also (also) eliminate the vortices which are a common source of drag, and add to the problem of lateral lift loss.

Pretty neat, huh?

Today we talked about aircraft and basic electrical drawings. Nothing earth-shattering, but interesting nonetheless.  There's an electrical diagram symbol for "Space Station." It's a boxy thing with a circle in it. Definitely not Buck Rogers approved.

I've been looking over the study guide for the test, and I'm really not too worried about anything at all.
One thing that surprises me of the things that we've apparently learned that I've since forgotten is that wet air (air with a absolute humidity) weighs less than dry air. That doesn't really make a lot of sense to me at first, but when I start to think about it, the water is vaporized and floats about in the air, instead of condensing and falling out. That means that the water is ligher than or as light as the air.

So, there ya go-- winglets and wet air.