Aerodynamically stable pod designs

[GoSlash27]

All,

 This is too short for a tutorial, so I'm going to just leave this here.

Are you having problems with reentry packages tumbling? Part placement and stacking order matters in KSP. There are some things you can do to reduce or even eliminate the tendency to flip.

Principles for aerodynamically stable reentry:

1: The center of gravity should be as close to the ablator as possible. Stack your capsule so that physically compact and dense components ride near the ablator, while large and light components with high surface area are far away. This creates a torque moment that tends to self-correct deviations.

To determine the correct order of series stacked parts, simply multiply their mass by their height. Highest values go closest to the ablator. Lowest values farthest away.

2: If you have solar panels, mount them as I have here. Slightly rotated, tucked in to keep out of the heat, and as far away from the ablator as possible. This will add drag to the "back" of the reentry capsule, acting like a drogue. Remember, physicsless parts such as surface mount panels don't apply mass and drag to their own center of gravity, but rather the center of gravity of whatever part they're attached to.

 This is a nice, stable design for an early career science capsule. If you folks have stable designs, feel free to share!

Best,
-Slashy

 

Edited October 28, 2016 by GoSlash27

[bewing]

I think you guys are trying too hard. I just reentered this at Kerbin with a 44km Pe from beyond Minmus and it worked great. It's even aerodynamically stable (OK, with the wrong end pointed forward ... quibbles).

(Those happen to be type D Structural Wings, but the AV-T1 winglets work too.)

[Tyko]

I had no probs with just a .625 heat shield, the sample container and the parachute. The delivery vehicle detached at about 100Km and the collection pod righted itself with the heatshield down. The return I tried was from Sun orbit - just outside Kerbin SOI - with the pod moving at over 3200m/s when it hit the atmosphere.

Edited October 28, 2016 by tjt

[EpicSpaceTroll139]

I literally just use 3 parts for my science return capsules. The heatshield, the capsule, and the parachute. I use whatever probe it's attached to to put its periapsis at 22km or so and stage the parachute with the decoupler. The parachute only opens when it's safe, so it's just a matter of waiting until it lands or splashes down. The original probe can even reboost into orbit and be used as a relay or go fetch more science if need be . (Or you could throw it away )

[JAFO]

On 10/28/2016 at 9:21 AM, GoSlash27 said:

 This is a nice, stable design for an early career science capsule. If you folks have stable designs, feel free to share!

Many thanks, Slashy.. been having some re-entry problems with my basic setup, but this solves them nicely.

Only thing I've changed was to reduce the number of solar panels to 3. After all, when it comes to Caveman Challenges, part-count is everything!