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Deploy Fairing

I suck at making rockets. Help?

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Either it runs out of fuel, flips over and explodes, or just plain out doesn't work at all. Somehow, KSP has some sort of excuse to make my rockets not work, how DO i actually get them into orbit? 

P.S How do i get an Asparagus fuel setup?

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Hello, and welcome to the forums!  :)

36 minutes ago, Deploy Fairing said:

Either it runs out of fuel, flips over and explodes, or just plain out doesn't work at all. Somehow, KSP has some sort of excuse to make my rockets not work, how DO i actually get them into orbit?

Don't feel too bad-- we've all been there!  KSP can be very daunting at first, mainly because there's a steep learning curve and there are many ways to "do it wrong".  And because there are so many different things that you have to do "right", it can be tricky to get there just by trial and error, which may go a long way towards explaining the frustration you're encountering.

The good news is that once you know the "right" way, getting to orbit is pretty straightforward, especially after you've had a bit of practice.  And you've definitely come to the right place for advice!

Anyway, there are plenty of people here who can help you... but it really helps us to have something specific to work with.  If you could post a screenshot of your ship, it would be a lot easier for people to offer specific suggestions.

Reason why that's needed:  there are many, many ways to "do it wrong" in KSP.  Depending on exactly what you're doing, there could be any number of reasons why you're having problems.  Seeing a picture will help us know what your actual issue is, so we can give useful relevant advice.

Instructions on how to post a screenshot in spoiler below:

Spoiler

To post a screenshot:

  1. Take a screenshot in-game by pressing F1.  This puts a screenshot into the "Screenshots" sub-folder of your KSP folder.
  2. Go to http://www.imgur.com (you don't need an account or anything)
  3. Click the button up top to make a new post
  4. Drag your screenshot image into the "drop images here" thingy on the page
  5. When your imgur page comes up, right-click on the picture and choose "Copy image location"
  6. Paste that URL into your forum post.
  7. It will automagically get converted into an in-line image.  Ta dah!  :)

 

Even though it's hard to give some specific advice without a screenshot, here are some general tips with some of the problems you're mentioning:

36 minutes ago, Deploy Fairing said:

runs out of fuel

Lots of possible problems.  To take just a few examples of the possibilities:

  • You don't have enough fuel, so you're running out.
  • You have too much fuel, so your rocket's too heavy and you're wasting fuel.
  • Your engines are too weak, so you're wasting too much fuel fighting gravity.
  • Your engines are too strong, so you're lugging too much dead weight, and also going too fast too soon and fighting aerodynamic drag.
  • You're using the wrong engines on the launch pad.  Some engines only work well in vacuum and get tiny thrust and horrible fuel efficiency if you use them at sea level.
  • Your ship isn't streamlined enough, so you're wasting too much fuel fighting drag.
  • You're "flying it wrong" and not following a good path to orbit.
  • You don't have enough stages.
  • You have too many stages.
  • You have the wrong mass distribution among your stages.
  • And on... and on... and on... :wink:

You see the problem.  It's just about impossible to answer the question of "what you're doing wrong" without seeing what you're doing.  Screenshot please!

 

36 minutes ago, Deploy Fairing said:

flips over

This is a very common problem in KSP.  It means that your rocket is aerodynamically unstable.  In technical terms, it means that your center of mass is behind the center of dynamic pressure, whereas you want it to be in front.  In less technical terms, it means your rocket is built in such a way that it's like trying to throw a badminton birdie feathers-end first.

Again, a screenshot would help diagnose the problem.  But speaking generally:  You want your center of mass up near the front, as high as possible.  You want the front end of your rocket to be as streamlined as possible.  And you want to have fins down low on the back end to help keep it pointed the right way.  To summarize,

  • Heavy, pointy things in the front
  • Lightweight, draggy things in the back
36 minutes ago, Deploy Fairing said:

how DO i actually get them into orbit?

  1. Build your rocket with enough dV and appropriate TWR (this is the "running out of fuel" problem)
  2. Build it so it's aerodynamically stable (this is the "flipping" problem)
  3. Fly it in an efficient path to orbit (this may also be contributing to your "running out of fuel" problem, if you're doing it wrong)

Those are very broad statements that probably won't directly help you-- what you need is specific advice.  But once we see a screenshot, I'm sure lots of specific advice will be forthcoming.  :wink:

 

36 minutes ago, Deploy Fairing said:

P.S How do i get an Asparagus fuel setup?

Lots of helpful advice available here... but I'd suggest that you wait until you've got a good handle on basic rocket building & piloting skills before you start getting fancy with the asparagus.  You can get to orbit just fine without asparagus; walk before you run, would be my advice.

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1 hour ago, DerekL1963 said:

It can also mean you have insufficient control authority.

To be clear:  It definitely means that the rocket is aerodynamically unstable.

  • An aerodynamically stable rocket won't flip, even if it has zero control authority.
  • A sufficiently unstable rocket will flip, even if you have a lot of control authority.

Sometimes, if a rocket is only slightly unstable, adding control authority will help to partially stabilize it, by giving it the ability to recover from minor deviations from prograde.  But in my experience, "make it more stable" is generally more broadly useful than "add control authority".  Besides... a rocket shouldn't need any control authority during launch (or, at least, only a very tiny amount).  Assuming that it's aerodynamically stable and that one is flying a reasonably well-executed gravity turn, the rocket steers itself, and basically flies itself to orbit.  If you're steering a lot, then you're Doing It Wrong™.  :)

But anyway, as has been mentioned, what we really need to see is a screenshot, then the answers will become clear.

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7 minutes ago, Snark said:

This is a very common problem in KSP.  It means that your rocket is aerodynamically unstable.

It can also mean you have insufficient control authority.  But, either way, it's impossible to diagnose without a picture or a .CRAFT file.

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2 hours ago, Deploy Fairing said:

Either it runs out of fuel, flips over and explodes, or just plain out doesn't work at all. Somehow, KSP has some sort of excuse to make my rockets not work, how DO i actually get them into orbit? 

P.S How do i get an Asparagus fuel setup?

1. To not flip over always keep an eye on COM (yellow ball) and COL (blue ball) when desigining your rocket. The blue ball should be below (or at least match) the yellow one. If it isn't, keep adding/moving winglets to the bottom and see how it moves down.

2. Basically two stages are optimal to get into orbit. That enables you to use first stage for initial acceleration and then jettison it, and not to carry that heavy weight all the way into orbit. Start with designing your upper stage first considering the No 1 COM/COL rule. Then build the first stage capable of carrying all of the stuff. Again, watch the COM and COL.

3. If your rocket doesn't move after lauch then you most likely have too low TWR (thrust to weight ratio). It should be greater than 1, good value is something around 1.2.

4. You may run out of fuel if you have not enough dV or improper drag profile. You may increase dV by adding fuel or decreasing weight. But as you do that your TWR and COM/COL change, so watch them.

5. As for dV and TWR, you may calculate them by yourself or just use the Kerbal Engineer Redux mod that just does that for you. You'll need total 4200-4500 dV to achieve low Kerbin orbit.

Edited by Ser

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6 minutes ago, Snark said:

Besides... a rocket shouldn't need any control authority during launch (or, at least, only a very tiny amount).  Assuming that it's aerodynamically stable and that one is flying a reasonably well-executed gravity turn, the rocket steers itself, and basically flies itself to orbit.  


Assuming of course that one is very good at designing rockets with just enough stability to not tip, and just enough control to start the turn, and properly balanced to steer itself.   Most KSP players either aren't that good or aren't that experienced.  My advice is aimed at that majority of players.

For those of us in that majority, adding a bit of control authority alongside (or instead of, depending on the design) re-arranging the CoM/CoL is a perfectly valid way to build a rocket that does not flip and I object to being told that it isn't and that I'm "doing it wrong" because I don't build rockets that meet your standards.

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1 hour ago, DerekL1963 said:

Assuming of course that one is very good at designing rockets with just enough stability to not tip

Designing aerodynamically stable rockets isn't super difficult.  It's not necessarily obvious to a new player, and it's not necessarily easy to discover the basic how-it-works by trial and error (because when a rocket flips, you don't necessarily know why), which is why it's great that there's a forum like this one to give folks advice.  :)

But following the mantra of "heavy pointy bits up front, lightweight draggy bits in back" pretty much does the trick.  Even something as simple as knowing that you want your CoM as high as possible can really make the difference.  (For example, I've seen plenty of people led astray by thinking that they want their CoM to be as low as possible, which is precisely exactly the wrong thing and is indeed precisely what's causing their problems.)

I've seen a lot of players complaining in this forum that "my rocket keeps flipping".  These are, for the most part, great threads.  They lead to lively discussion, informative posts by knowledgeable users, and successful conclusions.  And in virtually every instance, the cause of the problem is "this rocket is aerodynamically unstable", and the solution is generally "make it more stable".

1 hour ago, DerekL1963 said:

just enough control to start the turn

This is also fairly easy.  "Just about any control authority at all", especially for the kind of small ships that newbies are likely to launch.  "Too little control authority" is generally not a problem, because for a small rocket, even a Mk1 command pod has enough torque to start the turn.

1 hour ago, DerekL1963 said:

properly balanced to steer itself

This isn't even a thing.  A rocket is either aerodynamically stable or it isn't.  If it isn't, it's going to flip.  If it is, then it's already balanced to steer itself-- the force of the wind will just naturally keep it prograde.  This is not a fine-tuned design problem, it's basically just "put fins at the back and heavy stuff up front and you're done."

All aerodynamically stable rockets steer themselves during a gravity turn.

1 hour ago, DerekL1963 said:

Most KSP players either aren't that good or aren't that experienced.  My advice is aimed at that majority of players.

My advice is also aimed at the majority of players.  The issue is that aerodynamic stability isn't necessarily obvious to the newcomer.  Lots of newbies have flipping problems, because they build things that aren't aerodynamically stable.  So they post here, and somebody points out the issues with their designs and how to make it aerodynamically stable, and they go and fix that, and then they don't have that problem anymore.

I'm basically in agreement with you-- the only real difference I have is that I'm asserting that for newbies with flipping problems, "aerodynamic instability is much more frequently the real issue than lack of control authority."

 

1 hour ago, DerekL1963 said:

adding a bit of control authority alongside (or instead of, depending on the design) re-arranging the CoM/CoL is a perfectly valid way to build a rocket that does not flip

It can be, depending on circumstances.  I would contend, broadly speaking, there are three categories of rockets here that are relevant to this discussion:

  1. Rockets that are aerodynamically stable.
  2. Rockets that are marginally, slightly aerodynamically unstable.
  3. Rockets that are badly aerodynamically unstable.

Rockets in category #1, by players who know how to design aerodynamically stable things, work just fine and don't need any control authority to stay pointed forwards, so they "just work" and control authority is nearly irrelevant.  (For stability purposes, anyway.  It can sometimes be helpful for fine-tuning the trajectory, for players who haven't quite nailed the gravity curve technique yet.  But that's not the primary problem that the OP is having in this thread, which is why I didn't bring it up.)

Rockets in category #2 want to flip, but not super strongly as long as one stays fairly close to prograde, so adding control authority can help tip the balance.  Even when it does work, it may be finicky and inconvenient in flight-- a typical result is "my rocket does fine as long as it sticks within N degrees of prograde, but go beyond that and it just goes berserk."

Rockets in category #3 are going to flip.  Adding control authority just won't work, because as soon as the rocket goes fast enough, it will overwhelm basically any control authority you have.

My post wasn't criticizing your advice.  All I'm saying is, my observation has been that when one doesn't know the specifics of a person's rocket-flipping problem, "make it stable" has more frequently been useful advice than "add control authority", because it applies to a much larger percentage of people with problems.  At least, that's been my observation in the forums since the new aero came out in 1.0.

Making the rocket stable will solve both cases #2 and #3, and will do so in a reliable, goof-proof way that's highly robust regardless of the player's piloting.  Adding control authority will solve only #2, not #3, and will put constraints on the player's piloting that may be difficult for a newbie.  And my observation has been that there are a lot of #3 cases out there among newbies-- my impression is that it's more numerous than #2.

So, I wasn't trying to say that "add more control authority" is bad advice-- simply that it may or may not help the OP's problem, whereas improving aero stability definitely will.

I wouldn't have even brought it up in the first place... except that I've seen cases of players having problems like "I keep adding <thing for control authority> and it keeps flipping", because they're under the misconception that control authority will solve their particular problem, when the real problem is that they're badly unstable.

 

1 hour ago, DerekL1963 said:

I object to being told that it isn't and that I'm "doing it wrong" because I don't build rockets that meet your standards.

Sorry, that wasn't my intention at all.  I've tried to make it clear that no aspersion or judgment at all was intended-- that's why I deliberately put the phrase in quotes or add a humorous ™ after it every time I use the phrase.  Certainly I don't have "standards" that I would expect anyone else to meet-- nor should anyone, in KSP.  This is an open sandbox game and anyone can play it any way they want; that's the whole point of this kind of game.  However you're playing the game, by definition it's the right way for you, if you're happy with it.

If someone has a very high-steering play style that works for them, great!  More power to 'em.  :)

...But steering-a-lot isn't actually needed, nor is it necessarily the least-difficult way to orbit, and it's easy for a newbie to be led to the impression that "I have to steer a lot in order to get to orbit", and that's not the case.  My observation has been that the most-often-helpful advice to newbies in the forum with rocket-flipping problems has been "make it stable", that's all.

In any case, it's all pretty much a moot point until we have more information about what the OP's rocket looks like and how they're flying it.  I expect all will then become clear.  :)

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Mr. Fairing,

As you've seen from the above exchanges, answers on this forum can get pretty detailed (not to mention intense). There are players on here with a ton of experience, so you get some pretty good answers to all kinds of different questions. Sometimes they can get a bit technical, though. I learned to play this game by feel and just trial and error long before I discovered this forum (which would've made life a lot easier).

For a new player, I would suggest what I always suggest, play through all the training missions, and in the tutorials section on this site, check out EtherDragon's fantastic "Why Does My FLIPing Rocket Always Flip Over". His explanation of a rocket's aerodynamics is incredibly simple and informative. A picture is worth a thousand posts.

Other than that, just stay at it. You'll get the hang of it. And it's rewarding beyond words. You never forget your first Mun landing.

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I more agree with DerekL1963 than Snark on this one. A perfectly passively stable rocket doesn't need fins at all. If you need fins, it's because your rocket is unstable to some degree without them.

Fins can help in two ways: by passively correcting slight deflections in your trajectory, using aerodynamics -- or by simply increasing the drag at the back end of your rocket through the mere dragginess of their existence. (Which is kind of the same thing, but the first is a non-linear response.)

Control surfaces do the same -- except actively, rather than passively. In this way, using control surfaces for active trajectory control can even make your trip to orbit less draggy overall -- because trajectory deviations are corrected sooner by an active system than by a passive one.

Additionally, the payload of your rocket is usually at the top. Its form is dictated by its function. That form is almost never a nicely pointy aerodynamic form. It also has a particular mass that is dictated by its function. So the whole concept of "moving mass to the front and making it pointy" can be somewhere between inconvenient and impossible. People will then start talking about fairings, but I think they're nuts for many reasons.

So I tend to think that it's much more important to learn how to launch an aerodynamically unstable, badly weighted rocket up to high enough in the atmosphere (without flipping it!) -- to the point where aerodynamics becomes unimportant and you can stage and zoom the rest of the way to LKO -- in preparation for the rest of your trip. Which can often mean going straight up, slowly, with plenty of SRBs to get you into the sky.

 

Edited by bewing
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okay @bewing I'll take the bait :D   Fairings - just like most other things in KSP - do have a bit of a learning curve, but they help immensely if your payload isn't pointy and aerodynamic.

For weight distribution make sure the fuel tank right behind the fairing is the last one to empty - either by having a circularization stage or by setting it's fuel priority lower than the rest in the stack.

With an aerodynamic payload and a full fuel tank up front it's usually easy to make your craft stable.

Edited by Tyko

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When you do want to try asparagus staging, check out this guide I made. It's fairly old, but still applicable. 

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All thanks for your help guys! I finally managed to land on minmus and back! :cool:

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