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Ok guys, I know some about aerodynamics, but i dont know EXACTLY how it works..

Maybe some of you can help me?

Cheers Theis (P.S. I couldn't find something on google, that REALLY explains it)

Well, I figured I may as well post what I know about aerodynamics, even if you already know what I'm telling you (Please discard my previous post )

Welcome to Dr. Charlie's Flight School

It is important that an aircraft is aerodynamic. If it wasn't, it would not be able to reach enough speed needed for it to fly, which leads on to the aircraft not attanining enough lift to fly.

An aerodynamic aircraft can get to higher speeds because it is not fighting as much "air resistance" (AKA "drag") than that of a not-so-aerodynamic aircraft.
But what is this "air resistance"?... I hear you ask. Air resisitance is the air particles hitting the aircraft as it flies. The faster the aircraft travels, the greater amount of air particles will hit the aircraft and slow it down.
Let's take a look at a very detalied diagram to show this effect:



The aircraft at the top of this diagram isn't as aeridynamic as that of the aircraft on the bottom of the picture. The blue arrows represent the air flowing over the aircraft as they fly. As you can see, the less aerodynamic aircraft causes a longer route for the air to travel, thus more air particles can hit it, causing more air resistance, meaning a slower speed of flight. The more aerodynamic aircraft is like a dart, slicing through the air, and causes the air to take a shorter route to travel around the aircraft, thus less air particles can hit it, causing less air resistance, meaning a faster speed of flight.

If you need more info, Dr Charlie will try to provide it.

Ok guys, I know some about aerodynamics, but i dont know EXACTLY how it works..

It really depends on what you mean by the term aerodynamics.  I found this article on the basic theory of flight if that's any help. http://www.aeromuseum.org/eduHowtoFly.html

Aerodynamics "is" (as a singular science) a pretty broad study. It simply means;  "How air moves".

Aerodynamics "are" (as in all the ways a plane is affected in flight) everything from aerodynamic efficiency (so eloquently diagrammed above) to aerodynamic mechanics (how a plane has lift, turns, banks, etc.).

You could study it all for years and still have things to learn..

There's a lot to know; there's something different going on with every part of an airplane in flight, and to fully understand it, mathematics and all, I'm pretty sure you'd need to go through an entire degree program.


I can't recommend a textbook for an engineer's perspective on what makes aircraft fly the way they do, but the best explanation of flight dynamics as they pertain to flying airplanes is found in Stick and Rudder by Wolfgang Langeweische. Still in print, and I'm sure excerpts can be found on the internet. The scientific principles are explained there in a way that is useful for flying airplanes, without getting into too much of the details required for designing them.
It's also the best book I've seen for learning to fly...

Theis, just be a little more specific (eg - how does a wing work/types of drag/propulsion etc) and I'm sure we'll be able to help in some way...  :)

Yep, specifics and I could tell you a lot.  I love aerodynamics, in fact, I want to be an aerodynamicist!  

BTW I was at the bookstore and they had the Theory of Flight.  I dont think im mathematically ready for it, opened up to a random page and went  There was a HUGE calculus formula (im taking calculus BC next year)

Heres something to get you started, its got the basics:

http://www.allstar.fiu.edu/aero/airflylvl3.htm

I think that how a wing produces lift and the basics would be of most interest

I think that how a wing produces lift and the basics would be of most interest

Dr Charlie's Flight School Is Back!  ;D

A wing produces lift because of it's shape and how the air flows around it. A wing, looking through it, is shaped like an aerofoil. An aerofoil looks like the following:



The rounded egde of the aerofoil is the "leading edge" of the wing, and the flat end is the "trailing edge" of the wing. The leading edge is round, and splits up the airflow over the wing. The airflow underneath can go in a straight line and flow faster, whereas the airflow over the wing has to go over the leading edge and down the wing, thus flowing slower. The faster airflow causes more air particles to hit the underside of the wing, causing a higher pressure. The slower airflow over the wing causes less particled to hit the wing, causing a lower pressure. As an aircraft trundles down the runway, the pressure increases on the uderside of the wing, eventually so much pressure is caused that the aircraft is literally lifted off the runway.

Dr Charlie will try to provide more info if needed

The slower airflow over the wing causes less particled to hit the wing, causing a lower pressure.

Ummm, not sure you got that right Charlie. The conventional explanation as taught since the early days of flight is that the airflow over the top is faster therefore reducing the pressure. (If you check Jake's link you will see that this has been disputed.)

Copied from the FS9 Learning Center. [quote]How Wings Work

Wings

Ummm, not sure you got that right Charlie. The conventional explanation as taught since the early days of flight is that the airflow over the top is faster therefore reducing the pressure. (If you check Jake's link you will see that this has been disputed.)

Copied from the FS9 Learning Center.

I see, thanks Hagar. Seems I mixed up what my Dad told me

When air meets the leading edge, some goes over the wing, some under. They MUST meet each other at the trailing edge, else you'd have a vacuum somewhere (and we know how nature feels about vacuums). Since the path over an airfoil is longer than under, the air over the wing moves faster. Faster moving air has lower pressure. The relatively higher pressure from the slower moving air under the wing, is the lift.

Oh dear, Bernoulli again. Like Langeweische, I agree that the pressure differential due to differences in velocity above and below the wing does indeed happen, but a wing produces lift primarily by forcing air down and back... and as Newton pointed out, there is an equal reaction for every action. Air flows down and back; wing tries to go up and forward. The ram-air (not Bernoulli-induced) pressure buildup under a tilted plane moving through the air is a factor also, but the action of the upper surface is more important.
If this were not true, then how could an airfoil with a cambered top and flat bottom be flown upside down? Sure, the region of turbulence on the upward-facing surface of the wing would cause the air above it to curve a bit, but that turbulence would create a little more drag...it's important that the air curve over that surface on its way aft (see Coanda Effect), but that's because a sufficient volume of air at a sufficient velocity must keep spilling down and back from the training edge in a coherent stream in order for the wing to produce lift.  And what about the bottom of this inverted wing, which is curved? What does Bernoulli make of that?
There are airfoils that are cambered on the top and bottom, in order to make inverted flight more efficient... how could they work with Bernoulli's priciples only if the lower side of the wing is not flatter than the top, eh? Discounting Bernoulli's theorem, you can see that with the right angle of attack, the wing, whether it's a standard or symmetrical airfoil, forces the air down and back as Coanda illustrated, and this action produces a lifting effect as Newton proved. Of course, thanks to the Coanda effect, the air flowing past a cambered mower surface might produce a negative-lifting effect as the curve of the wing forces it up and back, but it doesn't, generally, because of the angles involved, as well as the fact that flat or curved, and inclined plane moving through the air compresses air beneath it. There's your high pressure, which compensates for any pproblems caused by a curved wing bottom trying to throw air up and back. If it were only about pairs of molecules separating to take different paths past the wing, this wouldn't work nearly as well as it does.
 I know Bernoulli's ideas are gospel in many aviation textbooks, and Newton and Coanda are ignored, but ithe Bernoulli Effect, while real, I guess,  just ain't the thing that does the trick. There is in fact a pressure differential between the top and bottom of a wing in flight, but it's not the primary factor. I think the aerospace community has latched onto Bernoulli just to be different;  he is their boy, and other disciplines don't need his theorem as much.
I can't quote the mathematics here, but trust me, It's Newton and Coanda  who keep your plane in the air, not Bernoulli.
And most importantly, as a pilot I have found it much more sensible to think of this wing that's keeping my ass in the air as simply washing air down and back while compressing it a little beneath, rather than picturing molecules racing along different paths to meet in the same place.

To quote Langeweische:
Trying to understand the piloting of airplanes by concentrating on Bernoulli and Prandtl is like trying to catch on to tennis by studying just exactly how the rubber molecules behave in a tennis ball when the bal hits the court and just how the catgut behaves in the racket when the bal strikes: instead of simply observing that it bounces!