Project DG-Launcher

[N_Molson]

That's what I wanted to do first, but I think there is no mean to prevent air under high pressure to get between the shell and the DG (you cant really "lock" the shell to the DG). A complete fairing seems safer. Also, that would probably allow some escape system (impossible to do with Velcro, maybe later).

 

[Bloodworth]

That's what I wanted to do first, but I think there is no mean to prevent air under high pressure to get between the shell and the DG (you cant really "lock" the shell to the DG). A complete fairing seems safer. Also, that would probably allow some escape system (impossible to do with Velcro, maybe later).

Actually, a fairing over the DG would PREVENT any sort of escape system, not allow it. If you are using the DGIV, it is equipped with ejection seats. Also, encapsulating the vehicle in a fairing would cause what could be a catastrophic delay in the event that an abort is necessary. If the crew needed to abort, they would need to wait an extra second or two for the fairing to eject and clear before they could eject or separate the DG from the rocket. At the speeds that rocket accidents happen, this would most certainly doom the crew and craft.

 

[N_Molson]

I don't agree. The crew can't eject during ascent, for the obvious reason that the boosters engines would burn them or their parachutes. Also if you try to eject the crew while on the ground, you'll end up with 5 casualties (I've tried ). The DG ejection system is only efficient when the ship flies or glide more or less like a conventional aircraft, in an atmosphere thick enough to provide sufficient lift to the parachutes.

In our case, I think that only "huge acceleration-short burn" SRMs attached to the aft of the DG (maybe behind the engines) would provide any help (the nosecone means no escape tower).

Anyway, to be honest, the spaceplanes like the Shuttle depend completely on the reliability of the booster (in the case of Challenger, there was nothing that could have done, the explosion was almost instant).

NB : the fun part with the DG-Boosters is that even if you eject the crew, the booster will put a wrecked-DG into orbit as if nothing happened !

 

[Tacolev]

Fairing or not, If I'm not mistaken isn't the Launch-Abort-SRM doubling as final orbital insertion stage more or less a standard design element for in-line spaceplanes? Never mind that none have ever really been built and operated...

 

[N_Molson]

Yes, I think I will try something like that, because the launcher is still short from a few hundred meters/seconds DeltaV. A lightweight SRM short-burn second stage is probably the answer.

 

[N_Molson]

Well, I think I've got the final concept of the booster, it's working very well like that :



Now I have to work (a lot) on the meshes.

Thanks to Thorton for his useful advice.

 

[Tacolev]

Looks great already!

More than just appearance. With the common engine heritage the boosters are basically R-7 boosters, no?

 

[N_Molson]

Yes, they are supposed to be a minor evolution of the R7 boosters ; their fuel tanks capacity is increased by roughly 5%, which allows them to burn a few more critical seconds.

Roughly, the whole booster at liftoff produces 13 MN of thrust at liftoff. The NK-33 produce more than 5 MN, and the RD-117 the 8 other MN.

So, burning for a few more seconds really makes a difference !

 

[N_Molson]

I think I got the final design (boosters & fairing are jettisoned here) :

 

[mc_]

I'm still not sure the fairing around DG is a good idea - there is almost the same construction between stages and the last stage and DG, and its strange that only one of them causes "problems".
Just my suggestion: the last stage shoul have an aerodynamical nose (maybe to fit with DG engines), other parts is good as they are now.

Anyway, the launcher looks great. Can't wait for a test flight.

 

[N_Molson]

Working on the engines (here the 3x NK-33 and attitude control thrusters).

 

[N_Molson]

The upper stage (Block V) is nearing completion...

 

[N_Molson]

Finally, I found a way to add a copper layer inside the nozzles ! Now I must watch for the polys count, whiLe adding the final details (Verniers for boosters, roll control thrusters)...



And yes, a "light" version of the fairing will be available Notice that the full one has holes for the wings, now. I should add doors to allow the crew to get inside !

 

[mc_]

Each new screenshot shows that model keeps looking better and beter :thumbup: Keep going!

 

[wehaveaproblem]

aye, this is looking nice. Kudos.

Out of curiosity, what kinda polly count is this thing gone get to?

 

[N_Molson]

Very high I fear... It's only the third ship I model, and this project is especially complex for me.

But given the fact that my computer is 4 or 5 years-old, and I get around 15 FPS at liftoff. I guess it should run smoothly on "modern" configs with multicore and all that hi-tech stuff :lol:

Seriously, the core stage itself counts around 120k triangles. The 3 main engines are very poly heavy. :blush:

The good news are that it's that's a multistaged rocked. So, once the 8 boosters are jettisoned, things run smoothly. Also, since Velcro autopilot handles the ascent very well, it's not a big problem to have a "bad" framerate at liftoff. The boosters are set to disappear after 500 seconds.

That being said, I have no idea how OGLA would handle it.

The core stage and the boosters are nearing completion. The upper stage is almost done. I'm working on an alternative fairing also.

If someone wants to design a "russian-looking" launchpad, you're welcome

 

[N_Molson]

Here's the light fairing (unfinished, no textures) :

 

[wehaveaproblem]

wow, that will be high poly then! Not that that is a bad thing per se, but I do think it is always good to try and keep it as efficient as possible... plus people always seem to complain about high poly stuff around here

That aside, it's looking like a very crisp model. Grats.

 

[N_Molson]

The 8 boosters are highly responsible of this, because even if each one of them has an acceptable number of polys, acceptable x8 means... too much polys ! BTW, it's the first really complex model I work on, so I guess that high poly count is a typical beginner error !

Once they are jettisonned, it runs smoothly on my 4-years old config, the FPS is low (10-15) only for the first 125 seconds of the flight (no problems in internal view, of course).

I'm adding particle effects in place of the exhaust textures, it doesn't seem to affect the FPS that much.

I'm probably going for a Tuesday release :lol:

---------- Post added at 07:21 PM ---------- Previous post was at 01:17 PM ----------

Now with particle effects (for the 11 main engines, still have to do the verniers / RCS thrusters exhausts) :

 

[Usquanigo]

Excellent model. :thumbup:

Does make me wonder if it's a bit overkill. lol

One question though, why use a cover for the DG to booster interface, but leave the other section open? It looks cool, but I would think if the first one is covered the second should be as well. Even if it was something that was ejected higher up in the atmosphere to reduce weight once out of the thick air or something.

Also, could this be retro-engineered for other craft besides DGs?