Putting the 'role' back in role-playing games since 2002.
Donate to Codex
Good Old Games
  • Welcome to rpgcodex.net, a site dedicated to discussing computer based role-playing games in a free and open fashion. We're less strict than other forums, but please refer to the rules.

    "This message is awaiting moderator approval": All new users must pass through our moderation queue before they will be able to post normally. Until your account has "passed" your posts will only be visible to yourself (and moderators) until they are approved. Give us a week to get around to approving / deleting / ignoring your mundane opinion on crap before hassling us about it. Once you have passed the moderation period (think of it as a test), you will be able to post normally, just like all the other retards.

Kerbal Space Program

Burning Bridges

Enviado de meu SM-G3502T usando Tapatalk
Joined
Apr 21, 2006
Messages
27,571
Location
Tampon Bay
:bro:
give this a little more time (link says Beta), but Orbiter with a real, working 3d elevated Moon would be the real thing. Although I think KSP with super realistic solar system and rocketry can also have a great future, because you can do more.

By the way, you may have seen these videos, but the latest 3d visualization of the moon gives me a boner. With todays computer power they reach the point where they surpass even the best moving pictures, and with unknown detail like fields of small rocks looking at the Moon is nothing short of amazing. I bet the Apollo astronauts would say the same, but they had no time to look at the Moon.

 

potatojohn

Arcane
Joined
Jan 2, 2012
Messages
2,646
Well the moving pictures were filmed in Nevada, so it makes sense that the computer stuff would look more realistic

Is there some KSP mod that shows useful stats about the atmospheric performance of rockets?
 
Self-Ejected

Ulminati

Kamelåså!
Patron
Joined
Jun 18, 2010
Messages
20,317
Location
DiNMRK
Is there some KSP mod that shows useful stats about the atmospheric performance of rockets?

Ferram aerospace research, kerbal engineer redux, and mechjeb all give atmospheric performance data.

Stock game also gives you atmospheric/vacuum ISP of rockets if you expand the tooltip on the part.
But get Kerbal Engineer Redux. The DeltaV/TWR calculations per stage are a godsend. And the additional vessel info is very welcome when trying to land since it has a radar altimeter
 

Burning Bridges

Enviado de meu SM-G3502T usando Tapatalk
Joined
Apr 21, 2006
Messages
27,571
Location
Tampon Bay
I can confirm that. I installed Kerbal Engineer after Ulminati's suggestion, and it's taken 99% of the deltaV calculations from my back. It does not always show the correct numbers though, especially with really sophisticated staging.

Kerbal alarm clock is also great, it's the first tool of this kind that I can understand ;) For the time I use Hohmann transfers .. yay :)
 

potatojohn

Arcane
Joined
Jan 2, 2012
Messages
2,646
OK, I removed MechJeb and installed Kerbal Engineer. I wasn't using the autopilots, but the "warp to" feature was pretty convenient.

There's a standalone transfer planner: http://forum.kerbalspaceprogram.com/threads/93115-0-90-Transfer-Window-Planner-v1-2-3-0-(Jan-11)

Anyway I also installed some more cool (actually really hot) nuclear engines.

Np6t6rm.jpg


20t engine with 1500 ISP and decent thrust... balanced or OP? This gets into orbit with 3800m/s left
 
Self-Ejected

Ulminati

Kamelåså!
Patron
Joined
Jun 18, 2010
Messages
20,317
Location
DiNMRK
Nuclear engines are supposed to be awful in atmosphere
:rpgcodex:

Those are beyond broken. Even ignoring the Arno stats, they have twice the ISP and 9x the thrust of the existing NERVAs
 

potatojohn

Arcane
Joined
Jan 2, 2012
Messages
2,646
Those are beyond broken. Even ignoring the Arno stats, they have twice the ISP and 9x the thrust of the existing NERVAs
?

It's balanced by the weight, same as the stock nuke

LV-909 - Weight: 0.5t, ISP: 375
LV-N - Weight: 3t, ISP: 800
CCGC-7 - Weight: 20t, ISP: 1500
 
Self-Ejected

Ulminati

Kamelåså!
Patron
Joined
Jun 18, 2010
Messages
20,317
Location
DiNMRK
Those are beyond broken. Even ignoring the Arno stats, they have twice the ISP and 9x the thrust of the existing NERVAs
?

It's balanced by the weight, same as the stock nuke

LV-909 - Weight: 0.5t, ISP: 375
LV-N - Weight: 3t, ISP: 800
CCGC-7 - Weight: 20t, ISP: 1500

Er, no. ISP is fuel efficiency.
The NERVA has a maximim vacuum thrust of 60 (just looked it up) and a mass of 3 tons.
The CCGC has a thrust for 450 and weighs 20t.

So to get the same thrust with NERVAS, you'd need 7½ of them, for a total weight of 22,5t.
The cheat engine you're using has slightly better thrust/weight ratio than the stock engine and will get TWICE AS MUCH DELTAV out of the same mass of fuel.

On top of that, the drawback of the NERVA is that it's big, heavy and you need to haul it out of the atmosphere before using it. If you use the NERVA in atmo, it has a paltry thrust of 13.9 and an ISP if 85. your cheat engine has better ISP in atmo than the best stock engines has in vacuum. And it's 18x as powerful in atmo as the nerva.

Sorry bro. No matter how you look at the numbers, you may as well press alt-f12 and click the hack gravity button in the cheats tab.
 

potatojohn

Arcane
Joined
Jan 2, 2012
Messages
2,646
On top of that, the drawback of the NERVA is that it's big, heavy and you need to haul it out of the atmosphere before using it. If you use the NERVA in atmo, it has a paltry thrust of 13.9 and an ISP if 85. your cheat engine has better ISP in atmo than the best stock engines has in vacuum. And it's 18x as powerful in atmo as the nerva.
This is a red herring. Atmo performance doesn't matter for stages with TWR < 1, since other engines will provide most of the thrust.

Additionally at 10km, you already have ~90% of vacuum ISP.

Thus the 800 atmospheric ISP is a tiny advantage.

Sorry bro. No matter how you look at the numbers, you may as well press alt-f12 and click the hack gravity button in the cheats tab.
I'm looking at the numbers and I'm not seeing it. For example, here's a simple comparison:

bw7k3Dj.jpg

6KcNIjn.jpg

Seems pretty reasonable. The stock engine has much better atmospheric performance and better final TWR, the nuke gives 1.5km/s DV more in space.

Also, the nuke doesn't gain any benefit from dropping off empty fuel tanks since the engine itself is so heavy. If you staged the normal engine properly you could probably get the 1.5km/s back.
 

Burning Bridges

Enviado de meu SM-G3502T usando Tapatalk
Joined
Apr 21, 2006
Messages
27,571
Location
Tampon Bay
potatojohn, though this does not look like a lot of deltaV by itself, this allows to build massive nuclear stages. Now add even more fuel and put another stage with a NERVA engine on top of it, it might become extremely overpowered. Burrn time for your stage is only 6 minutes, compare that to 60 minute NERVA burns.

EDIT: I did a quick calculation, and for an 80 ton stage this engine would behave basically like a NERVA with 10 times the thrust/weight ratio => 10 times shorter burn times.

Clipboard01.jpg


EDIT2: Sorry, there is a mistake. Thrust is 450, ok so the thrust to weight ratio is "only" 5.6 not 7.5.

So in order to be balanced it should roughly have the same thrust as the NERVA, not 10 7.5 times more.
 
Last edited:

potatojohn

Arcane
Joined
Jan 2, 2012
Messages
2,646
You can asparagus stage NERVAs to get better TWR and DV values.

The biggest advantage then is that it reduces part count 10x.
 
Self-Ejected

Ulminati

Kamelåså!
Patron
Joined
Jun 18, 2010
Messages
20,317
Location
DiNMRK
No, the biggest advantage is the 1500 specific impulse. Assuming you want to move something large to another planet (space station, jool mothership), you'd usually use a cluster of NERVAs. Now you just use one of these and half as much fuel as you usually would.
If the things ISP was halved it'd be balanced. (then it'd basically be 8 NERVAs stuck together) Right now it isn't anywhere close.
 

Burning Bridges

Enviado de meu SM-G3502T usando Tapatalk
Joined
Apr 21, 2006
Messages
27,571
Location
Tampon Bay
Actually, the rocket with highest deltaV is the Popamole stack (I think it was Ulminati who first came up with it) with a single engine. Adding more engines just gives you more thrust and shorter burns, but not more deltaV.
The problem with single engine is that this design takes insane burn times (theroetically several hours).
The problem is with a new engine that has BOTH 2x the ISP, and 7.5x the thrust, you can have deltaV of 20-30 km/s with very reasonable burn times.
If that's what you want, fine. But it takes a bit of the challenge out.
 
Self-Ejected

Ulminati

Kamelåså!
Patron
Joined
Jun 18, 2010
Messages
20,317
Location
DiNMRK
You mean ASPERGER's staging? Yeah, it's hypothetically the highest deltaV, but in practice you have all kinds of problems shedding the spent tanks. Or do you mean the STFU™ jet/liquid fuel hybrid design that got rendered obsolete by the RAPIER?

I actually made an ASPERGER's MK II that worked pretty well. But it's gotten absurdly difficult to control after they updated the aerodynamics :M
 
Last edited:

potatojohn

Arcane
Joined
Jan 2, 2012
Messages
2,646
Yeah clearly there some huge amount of fuel you can put on it where the ISP advantage overcomes all other engines regardless of how you stage them, but for reasonable payloads this engine is not THAT much better.
 

Burning Bridges

Enviado de meu SM-G3502T usando Tapatalk
Joined
Apr 21, 2006
Messages
27,571
Location
Tampon Bay
You mean ASPERGER's staging?

Yes, that one where you split the fuel into increasingly small tanks and drop them one by one.

I also don't use it anymore, since it was such a pain in practice. Also ION engines have become so much more useful, there is not really a point any more. At least if you get your probes extremely light, ION drive is way better.

No matter what engine is used, my personal MaxDeltaV ranking would be:

1. single engine, Asperger Staging (-if you get it to work) (-insane burn time)
2. single engine, huge tank (+easy to build) (-insane burn time)
3. multi engine, huge tank (++improved burn time)

And I use stages in this order:

Last: ION (almost "unlimited" deltaV)
2nd last: LV-1 micro propulsion system. Can give a "free" push of some thousand m/s, if the probe is light enough (<1t )
3rd last: NERVA (afaik there is nothing better for interplanetary transfer)

As I wrote on the last page, I am working on a design that combines ION and LV-1 in the last stage.
The advantage is that LV-1 has reasonable thrust, while Ion can be used for almost free course changes, on long flights.

The only problem is how to get rid of the LV1 and tanks if it's empty, but that is mostly solved-

The two LV1's and Ion drive can work at the same time, or I switch one of them off during flight. Once empty, the chemical engines drop sideways, and the ship can cruise on with the Ion drive.

Together with a NERVA stage (4t fuel) the complete ships weighs 10t, and gives deltaV between 13 and 20 km/s (depending on when I drop the LV1+tanks).

Here you should see the basic idea.

KSP 2015-06-13 14-12-29-68.jpg


And with Solar Panels extended:

KSP 2015-06-13 14-13-31-82.jpg
 
Last edited:

potatojohn

Arcane
Joined
Jan 2, 2012
Messages
2,646
rusrO80.jpg


After many attempts that ended with the ship upside down in "ascent", I finally got "The Whale" into orbit.
 

Drax

Arcane
Joined
Apr 6, 2013
Messages
10,986
Location
Silver City, Southern Lands
Huh, I've been messing around with mod parts so long I don't recognise the vanilla parts anymore...
And, plus, I got used to Procedural Parts as a replacer for pretty much everything
 

potatojohn

Arcane
Joined
Jan 2, 2012
Messages
2,646
I will probably try that as it sounds very useful, although part of the challenge of KSP is finding the best combination of the parts that you're given.

I also did the first rendezvous & docking in KSP.

tBFrwq1.jpg


Pretty frustrating after being used to Orbiter's interface. Orbiter has an MFD that shows closest approaches 20 orbits into the future, a MFD for aligning planes, a HUD with the relative velocity vector with the speed and distance close by, and a MFD for aligning with a docking port. It's a much smoother experience.
 

As an Amazon Associate, rpgcodex.net earns from qualifying purchases.
Back
Top Bottom