Tuesday, March 20, 2012

Aerodynamics Part 1


I've been working on the aerodynamics in A New Zero, one concept that is difficult to understand is lift.  I've seen a few different explanations for what causes lift, but I wasn't really satisfied with them.  So to better understand it I decided to make the simulated wind tunnel you can see in the video.

The wing shape is the simplest shape that creates lift.  There's 4 sides, the two front facing sides are sloped to reduce drag and cancel each other out for force in the up and down direction.  The back bottom face is parallel with the wind direction, so pressure is basically neutral.  The back top face is what creates the lift, since it is sloped slightly away from the wind direction the pressure is less than the back bottom face and that creates an overall upward force.

The third clip demonstrates this effect, the fourth is a wing that creates no lift, and the fifth creates downward force.  In the sixth clip you can see what happens when there's not enough pressure, eventually the air flows completely around the wing and only drag is created.  The last two clips are a more rounded front face, and then a high angle of attack wing.

I'll be experimenting more with the fluid simulation, I'll post some more videos once I have some interesting things to show.

I also recently uploaded some of the music I've used for the videos, you can check it out here:
http://soundcloud.com/crypticsea/sets/video-music/

10 comments:

Andy Moore said...

nonononono!

I'm a ground-school flight instructor and we cover this quite a bit in class. The old-timey way of thinking about lift is what you are demonstrating and talking about, and in fact it was taught in classes up until the 90s. Turns out that effect does exist, but makes up less than 5% of total lift.

the other 95%? comes from airflow deflection. An airfoil changes the direction of the air passing over it; as such it must exert a force on the air. The air then exerts and equal and opposite force on the wing, producing lift.

There is a lot of debate as to the actual cause of the deflection, but a good starting point for laymen is checking out the coanda effect:

http://www.youtube.com/watch?v=AvLwqRCbGKY

PropagandaPanda(Ger) said...

Why you dont use the old Aerodynamics from version 0.78? I think they are great, flying make a lot of fun and it feels realistic enough ! ;)

coolguy1 said...

I have always liked the way the planes in ANZ flew there was something very right about it.

coolguy1 said...

In addendum to my previous post:

There has always been a really nice physicality to them even though I don't think the game has ever been true to life. This has never mattered though because of how stylized the game is. Indeed it does not seem to matter how a real plane should fly only that in ANZ the the plane flies like it feels it should fly.

Alex Austin said...

@Andy yesyesyesyes!
I know that most of what people call lift is really just using air as an inclined plane, but I wanted to do an experiment to generate lift using pressure differences.

@Prop and guy
The aerodynamics will be similar to 0.78, there will probably be less drag/heavier planes. There's a few reasons I want to do that, mainly for more interesting air combat.

THENIESMAN said...

i think the new flight with lighter planes will work great due to the fact that hopefully you won't stall for going a degree above 45degrees during a short takeoff either way i have and always will love anz!

PolimerJones said...

The lift video was cool. Did you make that program? Can you put it up for download? I'd like to mess around with it, putting different shapes in to see what happens...

Antotabo said...

I love your game. But your aerodynamic applet on aerodynamic applet, by the way it seem to works,won't even give you the slithest idea about the real aerodynamic behavior. The standard way to modelize flight behavior is with lift and drag curves as you might already know. I suggest you to stick with this so simpler and more accurate method.

Antotabo said...
This comment has been removed by the author.
Antotabo said...

And yeah, less drag would be awesome since we feel like flying in oil or something. A rate of fall (same as lift on drag) of at least 1/20 could give a more easy flying and better fights!!