Larger profile = better aerobrake?

[Motokid600]

What determines how much you slow down in a planets atmosphere other then altitude? If two craft enter the atmosphere at the exact same time, speed and angle which one will slow down faster? A larger craft with a large profile or a small one? What made me think of this is B9's airbrakes. If I were to deploy these during an aerobrake would they not result in a lower periapsis?

Edited July 30, 2013 by Motokid600

[Tw1]

The game doesn't really model drag that well, it's the same whatever shape you are, just what parts your ship is made out of.

Also, entering with two things at once could mean physics and drag aren't loaded for the second thing, and it doesn't slow down at all.

I had an Eve probe that kinda disassembled before I attempted aerocapture.

The main part got into Eve orbit ok, but the rest was put on a collision course for Kerbol.

[Frederf]

Mainly acceleration is force divided by mass. More massive ships of the same drag will be slowed less. Draggier objects slow more than slicker ones at the same mass.

Drag is orientation specific with several parts. Lift is also possible with parts that participate in that.

[strongest_2hu]

You can see from the drag equation that the force of drag is dependent solely on speed, atmospheric density, ship mass, and ship drag coefficient. http://wiki.kerbalspaceprogram.com/wiki/Atmosphere

Because of the way that acceleration and force are related, in KSP mass winds up cancelling out of the acceleration due to drag equation, which means that atmospheric deceleration depends only on speed, atmospheric density (which is dependent solely on altitude for a given planet), and mass-weighted coefficient of drag. Drag coefficient is the "drag" value given in the VAB/SPH, most parts are at .2.

Thus, two ships made of the same parts in different configurations will decelerate at the same rate; moreover, two ships made of completely different parts that share the same average drag value (a big orange fuel tank and a probe core, for example, both have drag=.2) will fall at the same rate.

If anybody wants to come in here and tell me what "minimum drag" in the .cfg means, as well as "angular drag," and how they play into the drag equation (if at all), please do.

[Frederf]

I believe angular drag is the drag of rotation as in how the air resistance slows a spinning object.

[Eric S]

If I were to deploy these during an aerobrake would they not result in a lower periapsis?

It would have a greater effect on your apoapsis, but it would affect periapsis. Aerodynamic drag is basically free retrograde thrust, and retrograde thrust mostly lowers the opposite part of the orbit that you're in, but unless you're at the periapsis or apoapsis, also has some effect on the rest of the orbit.