I cannot into spaceplanes.

[TerLoki]

So, I'm just looking for general advice here. I haven't been on KSP in a long while, and before I left I remember being really frustrated with trying to build spaceplanes or even fixed-wing aircraft of any variety. When I tried Kliper-style vertical launch something would always spin out of control, or snap off, or I'd get a bad stage separation that ripped off my engines. I tried horizontal take-offs, but those were even more disastrous, as everything I made just listed lazily to the left until it wingtip caught pavement and the whole thing cartwheeled itself to death. At least one I know COULD fly, I managed a weird hybrid take-off from the runway involving stabilizing clamps and it flew all the way to 60000m before running out of fuel. I even got the same results when using premade ships from mods and the vanilla game.

And now I'm trying again, and guess what? The results are the same. I just don't get what's wrong. I have symmetry on everything as close as I can possibly get it. The center of lift and center of gravity line up; AND center of thrust in the case of rocket-assisted launches. I even installed FAR for the first time thinking it might change at least something, but all that's changed is the addition of a stall warning to show me just how much I'm failing as my not-Kliper tumbles out of control from the sky.

Is there something I'm missing here? I mean, obviously this is something that can be done as I see awesome spaceplanes and other aircraft all over the forums, but I just can't figure it out for the life of me.

[KerbMav]

Take a look into the tutorial library:

http://forum.kerbalspaceprogram.com/threads/28352-The-Drawing-Board-A-library-of-tutorials-and-other-useful-information

And here especially:

http://forum.kerbalspaceprogram.com/threads/39141-Tutorial-How-to-make-your-first-SSTO

http://youtu.be/fAn0Ul8u5gs

[WhiteKnuckle]

The center of lift and center of gravity line up;

Aircraft are tricky, and there's a lot of little things you need to do to get them to fly right, so definitely read the tutorials KerbMav posted. But the one thing that jumped out at me from your post is the line I quoted, you want your center of lift (COL) behind the center of mass (COM), not right on top of each other. The COM will also shift as you burn fuel off, so make sure that even with zero fuel (right click your fuel tanks and you can set the fuel sliders to zero) the COM is still ahead of the COL.

[Claw]

As KerbMav said, The Drawing Board is a great resource. It can be a bit overwhelming, so here is the space plane section:

Space Planes, Single-Stage-to-Orbit (SSTO) Craft, and Other Advanced Designs

• Learn to fly in KSP with the stock Aeris 3A!: By Scrogdog. A few tips for aspiring spaceplane pilots on learning to fly, using the Aeris 3A as a trainer craft.
  
• Basic Aircraft Design - Explained Simply, With Pictures: By keptin. An illustrated guide to effective design for your own aircraft, whether space-capable or otherwise. Diagrams provide clear and effective visual references to aid construction.
  
• Basic Airplane / Space Plane Aero Tutorial: By Claw. An in-depth guide to constructing and troubleshooting aerodynamic craft, explaining the "why" as well as the "what" in detail. Best read after or as a companion piece to keptin's "Basic Aircraft Design" (also listed, above.)
  
• Sub's Plane / SSTO Design for Beginners: By subhumann. A simple and comprehensive guide to building, flying, and landing your first spaceplanes and SSTO craft, aimed at beginning players. Highly recommended for first-time spaceplane designers.
  
• How to Make a Perfect Space Plane: By zombie2u. Handy advice for your first foray into building space planes.
  
• Jod's list of aerodynamics issues: By Jod. A list of issues that you may encounter during various stages of spaceplane flight and their possible causes, as well as general construction and piloting tips.
  
• Spaceplane SSTO Troubleshooting Guide: By Dragon1260. Some more tips for diagnosing and fixing problems you may encounter with your SSTO spaceplane designs.
  

It is all very similar information that approaches from different angles. So hopefully something makes sense to you. When you read it, try not to get too bogged down in the details, but get a general idea overall.

A picture of what you are designing would help, then we could give you guidance on how to continue on.

Vertical launches with space planes is difficult because they are generally, by design, asymmetric from top to bottom. Even if they aren't too asymmetric, the lift they generate is a lot for a vertical launch. (Unless you're referring to VTOL.) Is this your goal? Are you planning vertical or horizontal takeoffs? When you say space plane, taking off horizontal is what most people do, but it isn't required. On takeoff roll, activate the SAS and try not to do any steering adjustments at high speed. That will often cause you to sway leading to a wingtip catching the dirt. However, once most space plane you usually have to accelerate fairly level, usually something less than 20 degrees nose high at higher altitudes. If you're still pointing straight up, you can get reasonably high altitude but won't stay in orbit very easily.

If you're getting to 60,000m on turbojets level then you're actually doing really well. After that, it's a matter of transitioning to jet engines. As for design, make sure your Center of Lift (CoL) is behind your Center of Mass (CoM) by a little bit. Keep the bubbles touching, but behind is a good starting point. The CoL should also be slightly high to the CoM, but that isn't strictly required. Keep the Center of Thrust (CoT) inline with the CoM. This isn't all there is to design, but without it your plane will be difficult to control. After that, there are a lot of different ways you can approach your design.

I haven't used FAR at all yet. I'm saving that till I get bored with stock space planes.

Not sure if any of that as a starter helps. If you have specific question it might be easier for us to provide answers. Otherwise start with the library above.

Edited January 31, 2014 by Claw

[capi3101]

^^^

This. Keptin's picture link is particularly helpful.

[jalapen0]

I like the polandball reference.