Build bigger and better rockets in career?

[TexRob]

So, I pretty quickly got to an orbit around the moon. I tried landing once and realized I had nowhere near enough fuel left to land, nevermind get back. So, I go back to the drawing board, and try and build bigger rockets, so I end up with more fuel while in orbit. I just end up with huge rockets that weigh so much that I still run out of fuel. What am I missing? I have built some very small, efficient rockets that can get me to the moon and back, but no matter how big I go, I seem to end up with barely better results. I don't want to just go look up a perfect design, but any tips to guide me in the right direction? I'm also shooting in the dark when it comes to figuring out thrust limiters, stages, etc. I kept thinking if I break it into stages, it would help, but the extra motors and coupling seem to negate that with all the extra weight.

Edited December 28, 2013 by TexRob

[Skyrunner27]

Can I see a picture of the crafts you are talking about.

[Specialist290]

A picture or two would help, definitely. We might be able to troubleshoot some specific areas of a given rocket that way.

That said, in general terms, to get the most "bang for your buck" out of the fuel you add, it's generally more effective to add it to a lower stage than to a higher one. As a general principle, you want the vast majority of your fuel to be in your launch vehicle, because the more mass you can shed through staging, the less unnecessary "dead weight" your engines will be pushing once you get into orbit.

You'll sometimes hear terms like "the rocket equation" and "delta-v" being thrown around; these are essentially ways to quantify how efficient your rocket is (and are quite well-explained here, if you're up for a little light reading).

Hope this helps

[Liowen]

One suggestion I would toss out there, without seeing the craft, is use the IVA mode to see how far from the ground you are at your current height. While the altimeter might say you are 2,500 m you might less 1,000 m from the actual surface. I didn't even realize this until my second landing and it actually saved me a lot in fuel once I did as I didn't have to keep burning so often.

[flightmaster]

I always use asparagus staging for my launch sections, it's one of the more efficient ways of staging but can potentially be kind of boring. Since the subassemblies feature was implemented, I use the same launch stage for every ship, it's kind of clinical in a way. Perfect for me

[TexRob]

My designs are embarrassing, as I don't know what I'm doing, so be kind!

The most basic one made it to the Mun on the first try and back, but barely (I got very lucky on my fuel).

http://imgur.com/a/Z69Tf

[TexRob]

Oh, and I have 97 science currently, and this is what I have for science thus far (added to the bottom of that album). The fact that I really want to do career mode and not sandbox means I guess I am making this harder on myself. I didn't know that career mode was so newly implemented until after I bought KSP. I just don't want the ease of having everything unlocked at the start, I want it to be hard and rewarding.

[Liowen]

My suggestion would be to stick a FL-T200 where you have FL-T100, this should give you enough fuel in the lander to be more than safe. Your ship looks fine though, in fact it mirrors my first Mun lander a bit (though I built mine in sandbox mode). I nearly made the rockets landing ger too far up on my first attempt, but I also learned that if the gear stays too low on the tank it will be more tippy.

http://img34.imageshack.us/img34/8821/pwk3.png

[technion]

The bottom one doesn't look far off being mun capable. Just to confirm, does it make a nice orbit around kerbin before those LV-909's fire? I think the only trick there is to build out the bottom stage to make that the case, because the top part is certainly capable of making it there and landing.

[Peppe]

Looks like enough there to get to the mun.

Does your rocket seem fast off the launch pad?

3-4 big solid boosters is probably a lot for the mass there. If it flies good you might just right click on the booster in the design building and scale their thrust back. At full thrust they might be wasting a lot of fuel fighting air resistance off the pad. A slow steady burn that keeps the G meter (right side of the navball) in the green is probably a good indicator you have dialed in the right amount thrust.

The last shot the staging looks a little odd. After you are in space you probably only need 1 engine for each stage for the mun/minmus.

I'd probably go

stage 1:

4 solids you have tweaked to not max out the g meter. Not sure how high they will get you maybe 10-15k

stage 2:

First LV-T30, should escape atmosphere with this and maybe start to round your orbit

Stage 3:

Another LV-T30 with enough fuel to circularize the orbit at kerbin and get a mun encounter

might be able circularize mun orbit after capture

Stage 4:

Whatever tiny engine is unlocked, looks like 909?

As long as you don't bring too much above it the medium 200 tank should be enough to land and return.

If you are short in a stage usually you want to add to the first stage to carry on through to end up with more available in the final stages.

[Skyrunner27]

Scrap the use of the Solid Rockets on the side unless your load is really affecting you TWR use them sparingly. You second stage seems a bit large to take to space. I would suggest cutting that back and putting it into your first stage. Your lander seems a bit small. Your side engines should be used on the lander. The amount of fuel currently on it is too little to land on the moon and return. Also sparingly use a upper stage to space rather use side boosters (Solid or Liquid) to get to space. Once in space your TWR won't matter till you land on the moon. I ran into the same problem early in my game to. The biggest fix I found was Asparagus staging. I will explain if you don't understand.

[TexRob]

Great info all. Ok, trying some tweaks, and will report back. Thanks!

[TexRob]

Oh wow, I was really screwing up stage one, the G meter help is going to prove to be what I was screwing everything up with I think.

[TexRob]

Scrap the use of the Solid Rockets on the side unless your load is really affecting you TWR use them sparingly. You second stage seems a bit large to take to space. I would suggest cutting that back and putting it into your first stage. Your lander seems a bit small. Your side engines should be used on the lander. The amount of fuel currently on it is too little to land on the moon and return. Also sparingly use a upper stage to space rather use side boosters (Solid or Liquid) to get to space. Once in space your TWR won't matter till you land on the moon. I ran into the same problem early in my game to. The biggest fix I found was Asparagus staging. I will explain if you don't understand.

Ugh, I am still having a lot of trouble. So, I will try cutting the solid boosters, but how am I going to get the thrust? I just read about aspargus staging. That seems radically different than what I am doing now though.

What is wrong with solid rockets?

[LethalDose]

I've had luck using one stage (usually Lander + FLT 800 + LV909) to transit from Kerbin to the Mun and begin my retro burn to deorbit the Mun. While I'm falling toward the Mun, I drop that stage.

The Lander is designed to have enough fuel to finish the last approach to land (usually < 3000 m), then return to orbit and then back to Kerbin.

The other thing you might try when getting up to orbit from the KSC is to get a suborbital path with apoapsis ~ 70-100 km, and then just coasting until Ap, instead of burning the whole way up. I've found that saves me loads of fuel. And I can launch smaller rockets.

[TexRob]

So, this is where I am now. I updated the album with the new asparagus design. I'm so close, but I can't quite get my trajectory to Mun done before I run out of fuel and need the lander fuel. The lander fuel with the 200 fuel tank seems like it won't be enough as well. I've got a lot to learn still, thanks for the help.

http://imgur.com/a/Z69Tf

[TexRob]

Making progress, but slow going. I made it to the Mun, almost toppled over at the last second! I'll just keep working at it, thanks for the help guys.

[capi3101]

Try sticking your lander legs on a set of Modular Girder Adapters; that'll widen the base of your lander and make it less prone to tipping over. When you get as far as Fuel Systems on the tech tree, you can replace that FL-T400 you're using and the Girders with a set of five FL-T100 tanks, one center and four outboard - with fuel lines running from the outboard tanks to the center and the lander legs attached to the outboard tanks.

Incidentally, you need Fuel Systems before you can even attempt a proper asparagus (those darn Fuel Ducts again...). I'ma gonna say you need to make them the next priority for your Science.

Since you made the Mün, I won't give out any pointers on the ascent and transfer stages - you've obviously ironed those out. I will say that SRBs have lousy efficiency, no throttle control and short burn time. Good thrust and that's about it - they're good to get a craft airborne that would otherwise start out not being able to (like the STS Space Shuttle). If you can take off without them, you don't need them - you're better off with a liquid-fuel engine setup.

[pigletx2]

You need to use asparagus staging for the launch stage if you don't use FAR. It's the greatest way to get the most bang out of your rockets, as you have the most engines running at once. And as always; 1: Remember to throttle down a little bit until your gravity turn or staging to save a bit of fuel. And 2: MOOOOOOAAAAAR BOOSTERS.

[capi3101]

Asparagus isn't essential for the launch stage (and you don't actually need to do a launch that way), but it is by far the most efficient way of doing things (by which I mean it affords the highest payload fraction of any type of staging - 15%+ of your total craft can be payload with a good asparagus setup).

Me, I like single-stage rockets - as inefficient as you can get - but only if the payload is light. Easy to design, not all that terribly difficult to fly. Low part count.

[LethalDose]

You need to use asparagus staging for the launch stage if you don't use FAR. It's the greatest way to get the most bang out of your rockets, as you have the most engines running at once. And as always; 1: Remember to throttle down a little bit until your gravity turn or staging to save a bit of fuel. And 2: MOOOOOOAAAAAR BOOSTERS.

Capi3101 is right, "You need to use asparagus staging for the launch stage is you don't use FAR" is just wrong. I've never used either, but I've made more Munar landings than I can count, with and without docking for fuel transfer.

I'm not going to argue that asparagus staging is easy and incredibly efficient, though. It is. I just think that if it were practical IRL, NASA would have been doing it for the last 50 years. They don't do it like that, though, so there's almost certainly some practical issues with it. Therefore, I choose to avoid it to suit my own RP/realism sensibilities and to maintain the engineering challenges the game presents (Asparagus is so easy and effective that, IMO, it subverts some of the game's challenge).

[armeggedonCounselor]

Out of personal curiosity, what is the best design with FAR?

[SRV Ron]

I'm not going to argue that asparagus staging is easy and incredibly efficient, though. It is. I just think that if it were practical IRL, NASA would have been doing it for the last 50 years. They don't do it like that, though, so there's almost certainly some practical issues with it. Therefore, I choose to avoid it to suit my own RP/realism sensibilities and to maintain the engineering challenges the game presents (Asparagus is so easy and effective that, IMO, it subverts some of the game's challenge).

NASA doesn't use it because in real life, the high powered pumps and complex plumbing needed for such a setup is too expensive to design and test. The closest that was ever used was the system for the Space Shuttle. Alternatively was the early Atlas which dropped two of its heavy engines part way during flight. The Soviets used strapped on liquid boosters that dropped off when their fuel was used up before the core stage used up its fuel.

However, in Kerbal engineering, which has none of those problems, asparagus staging works extremely well when you can get a perfect balance on your design.

Example, 109 tons in orbit with asparagus and SRB outer ring.