Suction Cups: How?

[Matt Leese]

Originally posted by GregT
Very little of a plane's lift comes from this, almost all of it comes from the angle of attack. Stick your hand out the window of your car, directly into the wind. Curve it, notice any difference? Now angle it up.

The only way I can think of to leagally create suction (good suction) is to use pnumatics to move a plunger inside a tube. If done right you shouldn't lose any pressure.

Greg

What you're talking about is the Bernoulli Effect. Basically, it means that as the speed of air increases, the density of the air decreases. In the case of an airplane, the curve of upper section of the wing causes the air to travel more quickly over the top than the bottom. This creates a lower air pressure on the top so the airplane lifts up.

Now, many modern planes use an "angle of attack." What this means is, that as you fly, depending on how much lift you want, you change the angle of the wing, which causes the curve "seen" by the air to change. This gives a change in the amount of lift.

Matt