[Project] CST-100

[francisdrake]

Quote:

Wouldn't it be somewhat uneven?

To reduce problems with uneven firing of the abort engines, they are angled outwards, so each thrust vector points approximately through the spacecrafts mass center.

In case one engine does not light up (or underperforms) the resulting force vector will push the spacecraft somewhat sideways, but will not lead to an uncontrolled rotation.

By angling out the nozzles some forward thrust is lost, but this is minor.
For 20° angle the loss is 1-cos(20°) = 6%.
About 200 m/s are needed for an abort, while we estimate the service module to have 400 - 500 m/s in its tanks.

[Urwumpe]

The tanks will likely have enough for an orbital mission on board, which is closer to 300 m/s. Which is still enough for an abort.

Also, it looks like the engines can be gimballed - at least some details on the renderings look like there are gimbal actuators installed.

[N_Molson]

Some texturing and meshing work on the Centaur nozzles again :



Still not perfect, but closer from reality.

Edit : I have to learn how those environnement maps work. They could make that chrome-engine-plumbing look really cool. It's almost impossible to have something that looks like chrome without reflexion.

---------- Post added 04-30-13 at 02:01 AM ---------- Previous post was 04-29-13 at 04:37 PM ----------

OK now this is getting interesting. I've put too much of it to see how it works, of course, but it looks soo nice ! Perfect for the engine plumbing.





I don't even understand how it can work so well without major framerate impact. Hail Jarmonik !!

---------- Post added at 12:27 PM ---------- Previous post was at 02:01 AM ----------

Yes, I think I begin to like it that way, still lacks some detail but we're getting there :



A decent preview of the Centaur/CST-100 combo :

[PhantomCruiser]

That 3rd one has to go in the manual, awesome job and great screenshot!

[ky]

Boeing has nothing on us (Except money, resources, etc)

[Urwumpe]

Well, the engine plumbing would likely be a nightmare, the RL-10 is not really simple. But then, you could at least make the combustion chamber the proper size and place the pumps in the proper shape and orientation :D




I think the important detail of the engines are the two U-shaped sections of the plumbing.

[N_Molson]

Well, I'd say that the engine model itself is hardly 50% complete, a lot of the plumbing is missing. The size of the combustion chamber is ok*, as I've used a schematic to get the proportions. One engine is mounted in the wrong direction, yes. The problem about that is that the 2-engines version flew only one time (1998 or so), and even then it wasn't on the Atlas V. So it's very hard to find good pics of the layout, and pics of the engine alone don't help for that (in fact it's like "hmm, where that end should be plugged where ?").



See what I mean ?

Then there is also all the wiring at the back of the Centaur, which is a real maze of cables, relays and boxes. Currently only the RCS system plumbing is modeled.

Also I'll have to make the SE version, and also the optional mission duration expansion packs (more He tanks for more restarts, more RCS for the additional ullage burns, heavier but more durable batteries). Maybe also different variations of insulation which would have an influence on the empty mass and the boiloff rates. I already found info from L-M about that.

There's a lot of work on that second stage. Ideally, it will work as a "stand alone", so you'll be able to use it with other rockets, or in a shuttle bay...

*On the above pics, the engines have not the extensible nozzle feature, or it has been removed, so the proportions look different.

[Kyle]

That pluming does look hard to model. I really wish I was better at mesh making, otherwise I would help out with that to save time.

[N_Molson]

If you want to help, you can also search for good pics of centaur stages, single or dual engine. It is quite time-consuming for me to search for that.

Of course some people do it the easy way and hide everything interesting behind a fictional casing (also notice the wrong shape of the nozzle) :

[Urwumpe]

I think the fine plumbing could be replaced by semitransparent textures, not really necessary to do. But of course: The violet and the red stuff in the centaur photo is removed before installation (violet) and before flight (red).

[N_Molson]

Found that cool pic :



Ours it the Centaur V (DEC for the CST-100). It never flown, so it is of course impossible to find any picture only. I can only speculate from the Centaur V SEC or Centaur IIIA pics...

[Urwumpe]

Did you already look at this file?

http://www.ulalaunch.com/site/docs/p...cleHistory.pdf

It is about the old version of the Centaur, without the lengthed tanks, but it has a lot of nice detail information, what was improved already compared to the other versions.

---------- Post added at 10:21 PM ---------- Previous post was at 10:17 PM ----------

And here is more about the upgrades to the Centaur stage... using hydrogen/LOX for RCS instead of hydrazine.

http://www.ulalaunch.com/site/docs/p...March-2010.pdf

[N_Molson]

Adding some cabling mess (the thin red and blue lines)