17th August 2013, 23:52
Trying to launch a spaceplane into orbit with asparagus system
I'm wanting to create a space carrier that will ferry smaller space planes around the solar system but I'm having trouble getting the space plane into orbit. Just a couple km off the ground the entire launch vehicle tips over cause the space plane has lift-generating parts, right? Pretty easy concept. Well, I tried to correct that by adding enough wing parts to the back to move the center of lift just behind the center of mass so it doesn't tip over (which looks ridiculous), but it still tips over and does flips. I assume that this is because the center of mass is shifting forward as the fuel is being consumed, so this means that even if this somehow kept the space plane from causing too much lift up front then the huge wing structures in the back would eventually cause it to flip the other direction. Any suggestions on how I get this thing into space without flying it (because the space plane was built to look cool, not function as a plane in an atmosphere)? Here is my ridiculous contraption.
Last edited by trind; 18th August 2013 at 02:11.
18th August 2013, 00:22
#1 Rule of KSP: simple is better.
#37 Rule of KSP: wing connectors suck.
Building surface-to-orbit launchers in the spaceplane hangar don't often work well. I'd instead recommend a spaceplane with jet engines and powerful air intakes - use the liquid fuel and oxidizer tanks instead of the liquid-fuel-only tanks. Those extremely fuel-efficient jet engines can get you up higher than 20 kilometers, burning no less than 50 units of fuel. Take off from the runway, use jet engines until you're out of air. From then on, use a liquid fuel and oxidizer engine. I wouldn't recommend the atomic engine because of how heavy and weak in thrust it is. You'll need to make orbit with that engine. Once you're in orbit, you probably won't have a lot of fuel left. Time to use those orbital refueling stations that you surely have!
Check out this video/miniseries by Macey Dean, it makes spaceplanes look easy. http://www.youtube.com/watch?v=nC_t9BfG_mU
18th August 2013, 00:32
Thank you for your suggestion. I'll give it a try with some other space plane designs. I wanted this one in space cause it looks cool but I don't think it's very stable in atmospheric flight. I've seen some youtube videos where people launch their space planes into orbit like I'm attempting to and it works, but they don't explain how they did it. It seems like I just won't be able to get this plane design into space.
18th August 2013, 01:22
I've successfully used rockets to launch space planes. The trick is to to build the space plane in the space plane hanger, then open the KSP folder, open your save game there, and copy the file across to the VAB. Then contruct the rocket underneath.
The wings on the spaceplane shouldn't cause too many problems with the lift they create. The problem is the plane is likely to have unbalanced weight on the rocket. The solution is pretty simple, just stick a few torque wheels to the rocket and then launch with SAS enabled and it should stay pointed in the right direction. Also don't forget to put lots of struts connecting the rocket to the plane to keep it in place on it's journey up.
18th August 2013, 02:10
Thanks Moar! I'll give that a try.
18th August 2013, 05:27
I never thought of doing that to port them across. I must say, I've found this whole thread pretty useful... Spaceplanes have been giving me hell.
Originally Posted by Moar Boosters
Although given my newness to orbital mechanics in general, so has most everything.
Sometimes, the way Jeb always returns for duty with a goofy smile after he crashes and burns weirds me out.
18th August 2013, 05:37
Transplanting your plane from SPH to VAB and adding the lifting stages there sure makes it a lot easier but it will not solve the OP problem
If you're going to launch your orbiter plane 'Hermes style' (on top of the rocket instead of hanging from the side) you should rotate your entire rocket 90 degrees. That way once you do your gravity turn one wing will point up, the other down. Now lift from the wings will be mostly ignored and you'll have a much more stable flight. I've launched many planes in this fashion both large and small. As long as I keep it 'knife edged' I never ran into serious problems.
18th August 2013, 12:33
Tex, what do you mean? Do you mean turning the space plane 90 degrees so that it's perpendicular to the rocket? Oh my god you're a genius. Let me try that.
Edit: I tried everything and nothing worked, except transplanting the ship file into the VAB. Doing that caused no instability during liftoff at all. It's like the VAB disables lift or something. Thanks guys, I finally got the P. Squirrelly McStudleycraft into space and did a horrible attempt at docking. I have to seriously rethink my RCS placement lol
Last edited by trind; 18th August 2013 at 13:41.
18th August 2013, 14:06
No, keep your plane sitting on top of your rocket just as you have now. Just rotate it 90 degrees so before launch one wing is pointing east, the other west. During your gravity turn your wings will be pointing up and down. If you have your wings pointing north/south (like they would for a normal plane take-off) you'll have a hard time controlling your rocket during your gravity turn.
Originally Posted by trind