Flipping During Reentry

[ww1612]

I try to land a 300-ton-rotcket on Eve, or 100-ton-rocket on Laythe.

Of course, I have SAS, the reaction wheel with sufficient battery, and the heat shield on the bottom for airbrake.

 

At first, the vessels can maintain its orientation, but it would always flip in the high atmosphere, then get destroyed.

 

In fact, I encountered very similar situation in KSP1, when I also tried to land a 300-ton-rotcket on Eve.

Some said it relates to the center of mass being too high, or need more control surfaces, or making the top parts more draggy.

Some said it is a bug about heatshield ("PhysicsSignificance")

 

So what are your thoughts about it? 

 

 

[18Watt]

@ww1612, welcome to the KSP Forums!

I haven't used the Inflatable Heat Shield in KSP2 yet.  However, in KSP1 the Inflatable Heat Shield generated a lot of drag.  That caused it to tend to enter the atmosphere with the payload under the heat shield.  The workaround I often used was to place another inflatable heat shield above the payload.

Think of it like an arrow:  The heat shield acts like the feathers on the arrow.  The feathers (high drag) will want to be at the back.  Aerodynamically, the way to correct that is to place equal or greater drag at the other end of your entry vehicle.  Since the Inflatable Heat Shield produces so much drag, an easy way to compensate for that is to just put another heat shield at the other end of your entry vehicle (payload).

 

Moved to KSP2 Gameplay Questions.

[Vanamonde]

I believe 18Watt has the right answer though I haven't built anything this large in KSP2 yet. 

[18Watt]

Here's some screenshots of how I used the inflatable heat shields at Eve successfully:

The upper heat shield is on a boom, to make sure the weight distribution keeps it pointed into the wind.

Seems to work fairly well.

 

 

[ww1612]

On 12/23/2023 at 7:09 PM, 18Watt said:

@ww1612, welcome to the KSP Forums!

I haven't used the Inflatable Heat Shield in KSP2 yet.  However, in KSP1 the Inflatable Heat Shield generated a lot of drag.  That caused it to tend to enter the atmosphere with the payload under the heat shield.  The workaround I often used was to place another inflatable heat shield above the payload.

Think of it like an arrow:  The heat shield acts like the feathers on the arrow.  The feathers (high drag) will want to be at the back.  Aerodynamically, the way to correct that is to place equal or greater drag at the other end of your entry vehicle.  Since the Inflatable Heat Shield produces so much drag, an easy way to compensate for that is to just put another heat shield at the other end of your entry vehicle (payload).

 

Moved to KSP2 Gameplay Questions.

Thank you for the advice.

 

In fact, I also use a similar design in KSP1.

Based on my experience, this configuration (one  Inflatable Heat Shield on the bottom, and the other on the top) works for the vessel <200 ton; if the vessel >300 ton, it would still flip.  

 

Furthermore, in KSP2, the Inflatable Heat Shield can not resist heat.

Even the one on the top would get overheat and explode during re-entry.