AERODYNAMICS
By José Pablo Luna Sánchez. 2008

Spacecraft3.dll can handle the following control surfaces:

Each surface need the following properties to be defined.
Do not worry about the apparently mysterious nature of each parameter.
This first part is about concepts.

Now you may wonder how to calculate those esoteric numbers.

With this tutorial you will find a tool called VLM.EXE
Click HERE so you find out how to obtain and understand some of those numbers.

Here is a table that shows what data you need for every control surface.

ATTACK
CHORD
AREA
ASPECT
LIFT
EFFICIENCY
DRAG
CD0
ANIM
VAIRFOIL
x
x
x
x
x
x
x
x
-
HAIRFOIL
x
x
x
x
x
x
x
x
-
ELEVATOR
x
-
x
-
x
-
-
-
x
RUDDER
x
-
x
-
x
-
-
-
x
AILERON
x
-
x
-
x
-
-
-
x
ELEVATOR TRIM
x
-
x
-
x
-
-
-
x
RUDDER TRIM
x
-
x
-
x
-
-
-
x
FLAPS
-
-
x
-
x
-
-
-
x
SPEEDBRAKE
x
-
-
-
-
-
x
-
x

For vertical and horizontal airfoil, drag data required is wave drag.
For flaps, drag refers to the maximum drag when fully deployed.
Aileron animation must be composed by two sequences, one for left aileron and another for right aileron.

Example:

[AERODYNAMICS]
VAIRFOIL_ATTACK=(0,0,-0.2)
VAIRFOIL_CHORD=5
VAIRFOIL_AREA=90
VAIRFOIL_LIFT=4
VAIRFOIL_ASPECT=1.5
HAIRFOIL_ATTACK=(0,0,-4)
HAIRFOIL_CHORD=2
HAIRFOIL_AREA=15
VAIRFOIL_LIFT=2
HAIRFOIL_ASPECT=1.5
AILERON_ATTACK=(7.5,0,-7.2)
AILERON_AREA=0.2
AILERON_LIFT=1.5
AILERON_RIGHT_ANIM=9
AILERON_LEFT_ANIM=8
ELEVATOR_AREA=1.2
ELEVATOR_LIFT=1.5
ELEVATOR_ATTACK=(0,0,-7.2)
RUDDER_AREA=0.8
RUDDER_LIFT=1.5
RUDDER_ATTACK=(0,0,-7.2)
RUDDER_ANIM=6
SPEEDBRAKE_DRAG=4
SPEEDBRAKE_ATTACK=(0,0,-8)
SPEEDBRAKE_ANIM=10

There is still some room for exploring here.
You may have questions, and probably you may need to experiment a bit and share what you learn at the forums.
Aerodynamics is uncharted territory for many addon makers.
So your contribution in this arena could be very valuable.


REFERENCE

If you would like to learn more about aerodynamics, visit these sites

XFOIL
Subsonic Airfoil Development System (free software tool)
http://web.mit.edu/drela/Public/web/xfoil/

Airfoil Design
http://www.aerospaceweb.org/question/airfoils/q0035.shtml

Ask a Rocket Scientist Archive
Site with many interesting topics on aeronautics
http://www.aerospaceweb.org/question/list.shtml

Aerodynamics for students
http://www.ae.su.oz.au/aero/contents.html

NASA - Welcome to The Beginner's Guide to Aeronautics
http://www.grc.nasa.gov/WWW/K-12/aerosim/

Vortex Lattice Method (3-D)
For developers with some knowledge on aerodynamics (free software tool)
http://www.ae.su.oz.au/aero/vlm/vlm.html