Questions on Spacecraft3 aerodynamics

[ar81]

I have been giving this EXE tool a try
http://www.ae.su.oz.au/aero/vlm/vlm.html

I have some questions.

1.If wing has an incidence angle so front border is higher than rear border, where should you have more pressure? In the rear or front side of the wing? This is because I do not understand what is a positive and negative Alpha (angle of incidence)

2.Is it reasonable to think that the region with highest pressure is the one where you have the attack point?

3.If you have CD, how do you calculate Wave drag?

4.When you calculate area of wing in Orbiter, do you consider only one wing or both? If it has tailplane, is tailplane part of horizontal airfoil area?

5.Should area of ailerons and flaps and elevon be removed from the horizontal airfoil area?

 

[Eagle]

...

4.When you calculate area of wing in Orbiter, do you consider only one wing or both? If it has tailplane, is tailplane part of horizontal airfoil area?

5.Should area of ailerons and flaps and elevon be removed from the horizontal airfoil area?

4. Both wings.
5. I think they aren't included in the airfoil area. Try flying with no airfoil area and only ailerons, flaps and elevons to be sure.

Don't know the answer for anything else. I just play with the numbers until I get something that looks right, makes some kind of sense, and is playable.

 

[starbird]

1.If wing has an incidence angle so front border is higher than rear border, where should you have more pressure? In the rear or front side of the wing? This is because I do not understand what is a positive and negative Alpha (angle of incidence)

Incidence and angle of attack are 2 different things. Angle of Attack is the angle that the wind is hitting the wing, compared to the mean chord line.

Incidence is the difference between chord lines, these are compared to say, wing and tail, or wing and thurst line, or wing and fuselage centerline.

In the manual for that program, it says it lets you adjust the incidence of the tailplane. There are reasons to add a positive or negative incidence on the tailplane (compared to the main wing), if its above or below the main wing, or for trim purposes.

The videos at the bottom of this page might help you visualize the pressure distribution of an airfoil.

http://www.mh-aerotools.de/airfoils/velocitydistributions.htm


I don't understand #2.

3.If you have CD, how do you calculate Wave drag?

This page might help

http://adg.stanford.edu/aa241/drag/ssdragcalc.html