Project CST-100

[Capt_hensley]

I also might be able to rebuild the CST if Capt_Hensley doesn't have time to do it,

Yea Verily! Go forth and be fruitful, you guys are doing a great job, she's coming together quite nicely.

 

[ky]

The heatshield is the only thing thats stumping me right now, everything else is pretty much done. If Capt_Hensley could model the heatshield if I sent him the model, then everything would be set.

 

[Urwumpe]

The heatshield is the only thing thats stumping me right now, everything else is pretty much done. If Capt_Hensley could model the heatshield if I sent him the model, then everything would be set.

What is the problem with the heatshield? Isn't it a simple parabolic shape?

 

[ky]

What is the problem with the heatshield? Isn't it a simple parabolic shape?

The thing with the heatshield is that it isnt curving like it is supposed to in sketchup. If I try to extend it down so it curves out to the sides, it does not extend it. The difference between the two is shown in the pics

 

[Urwumpe]

The left one looks correct for an ablative heatshield... the right one rather like the inner wall of the heat shield.

 

[ky]

The one on the left was used on the original capsule by Capt_Hensley.

 

[Urwumpe]

The one on the left was used on the original capsule by Capt_Hensley.

Yes, and it looks pretty well... remember that the heat shield ablates and looses a few inches during reentry.

This here is a rather extreme example, but the heatshield of the CST-100 is not different in behavior:

There might be some more reserve if the heat shield is used for both LEO and lunar returns, but generally it should be even less than for Galileo, if you can design with more confidence.

 

[ky]

What I meant in the original post was that Capt_Hensley's original heatshield wont fit on the model that I'm currently making and I would have to make it from scratch. The pic on the right where you said that it looked like the heatshields inner wall is the result when I try to create the heatshield shape in Sketchup.

 

[Urwumpe]

What I meant in the original post was that Capt_Hensley's original heatshield wont fit on the model that I'm currently making and I would have to make it from scratch. The pic on the right where you said that it looked like the heatshields inner wall is the result when I try to create the heatshield shape in Sketchup.

Why doesn't it fit?

 

[ky]

Why doesn't it fit?

It fits, it isn't smooth with the model as it should be.

The edges of the capsule are jutting down into the heatshield, instead of blending into it.

 

[N_Molson]

Urwumpe is right... Here is a pic of Apollo CM (Skylab 3) :

When assembled, you can see a bit of the shield between the SM and the CM (Apollo 15, pic from the LM) :

So the diameter of the shield is slightly larger than the SM or the CM, that's normal.

---------- Post added at 07:24 PM ---------- Previous post was at 07:09 PM ----------

The edges of the capsule are jutting down into the heatshield, instead of blending into it.

I see... I think you should add more faces to the capsule, it would help. 24 is a bit low, try 48 or even 60. The more faces, the smoother the model (and also the more demanding for the display hardware). The other problem is that the shield and the capsule don't use the same method to organize their faces, so they can't match perfectly anyway. In such cases, I would try to add another "cut" cone section right over the junction, to hide it. It must be very very close from the meshes. Sometimes tricks like this are necessary.

 

[Capt_hensley]

I use a minimum of 36 segments, 1 for each 10 degrees of radius. In some cases to make the shape smoother I used 60+ segments.

In this case there are 20 verts in 1/4 of the shape, which suggests I used 80 segments in the heat shield portion.

 

[ky]

I use a minimum of 36 segments, 1 for each 10 degrees of radius. In some cases to make the shape smoother I used 60+ segments.

In this case there are 20 verts in 1/4 of the shape, which suggests I used 80 segments in the heat shield portion.

Thanks :thumbup:. This is a cutaway of the capsule:

---------- Post added at 07:13 PM ---------- Previous post was at 06:39 PM ----------

Exported it a mesh just to see how large it is, its only 923 kb

---------- Post added 07-26-13 at 03:17 PM ---------- Previous post was 07-25-13 at 07:13 PM ----------

Samuel Edwards pointed out a flaw in the CST mesh that I corrected in this new screenshot, so the model should look more like the cutaway pic.

Also, don't know which picture to use for making the thrusters, since nothing is in stone yet for Boeing.

 

[Donamy]

You could look at my dragon mesh, to see how I did it if you wish, and you could also look at my parachutes.

 

[N_Molson]

The parachutes are done already

Nice progress ky !

 

[ky]

The heatshield is slowly coming along, though I think I'll have arthritis by the end of this :lol:

---------- Post added at 02:00 PM ---------- Previous post was at 01:03 PM ----------

Heatshield complete

 

[N_Molson]

though I think I'll have arthritis by the end of this

Yes, a mouse is definitively not the best tool to make 3D ! But what else ? Maybe some 3D movement-tracking sensors on the hands, so that you could shape models like clay. :hmm:

Heatshield complete

Everything seems to fit nicely, this time, good !

 

[ky]

Like I said before, the only problem right now is which picture to use as reference to make the thrusters, since Boeing has released a few pictures with different configs.

 

[N_Molson]

Use the latests. The pics you posted about the press events give some indications, the thrusters locations are the black areas.

They are pretty consistent with your last model ; it also works pretty well in the sim from a physics point of view. I think you can keep it this way.

 

[ky]

Placing Thrusters