How do I get this to orbit (or design large SSTO's in general)?

[Destroyer713]

So I had the brilliant idea of making a space station in LKO, and that I would bring the rather large pieces up with a SSTO. Problem is, I literally have no idea how to properly make one that can reach orbit, and I'm having problems with the one I did try to make.

Craft File: https://www.dropbox.com/s/xmlozrqo44ova71/Starlifter%20Mk3.craft?dl=0

Some things to note about this thing:

- It has a lot of clipped fuel lines. I know those cause drag, but I'm not sure how else I'm supposed to get the fuel from the wings to the engines without directly attaching the engines to them.

- The center of lift seems to be a bit high compared to the center of mass. Is that why I'm having difficulty pitching up?

- I'm not sure if I have enough engines, or if I went overkill with them. Same with the wings and control surfaces.

- The Mk3 Cockpit is likely redundant with the probe core, I'm aware. It's mostly an aesthetic thing.

- Yes, I need Solar Panels. I didn't exactly get around to putting those on somewhere.

You guys happen to have any advice?

Edited September 8, 2015 by Destroyer713

[Reddeyfish]

you don't need any fuel lines with spaceplane engines; they drain equally from all tanks, just like RCS.

[GoSlash27]

Destroyer,

^ This. Also...

Your center of lift is too far behind your center of mass, so your elevators have insufficient leverage to get the nose up.

Your fuel supply is too far back as well as too little to get you to orbit and your payload is too far forward. When you get to orbit and jettison the payload, your spaceplane will probably be unflyable on reentry.

For a rough guide, check out this thread:

http://forum.kerbalspaceprogram.com/threads/133668-simple-rule-to-build-spaceplanes

Also, there are lots of good threads and tutorials on spaceplane design and construction. Also check the challenges, especially "Pro SSTO" and K-Prize. Lots of good starting points and ideas in there.

Best,

-Slashy

Edited September 7, 2015 by GoSlash27

[Edax]

Destroyer,

Your center of lift is too far behind your center of lift

Best,

-Slashy

Huh? Awfully paradoxical.

[GoSlash27]

Huh? Awfully paradoxical.

Typo. I've fixed it...

Best,

-Slashy

[Nothalogh]

Also, you seem dreadfully short on oxidizer for the rocket part of the ascent and orbital maneuvering

[Hagen von Tronje]

This gets said a lot, but an SSTO doesn't have to be a spaceplane. Rocket SSTOs are significantly easier - easy enough that several times I've tested lifters that turned out to attain LKO in the first stage alone without particularly aiming to do that. They're also straightforward to recover - most any rocket engine or fuel tank will have more than enough heat tolerance to deal with reentry from LKO without a heat shield, at least on normal settings.

I love me some spaceplanes, but if I'm actually trying to build something in orbit, I'd rather just save the hassle and use a rocket tug. I like spaceplanes for personnel transfer though, that's just a simple rendezvous so I'm ok with being a victim of style for that.

[Destroyer713]

you don't need any fuel lines with spaceplane engines; they drain equally from all tanks, just like RCS.

Well color me surprised. The Engineer's Report always warned me of "Unused Liquid Fuel/Oxidizer Resources" whenever I attached stuff radially, so I always assumed I needed fuel lines to even make them work. Glad to know I was wrong!

Destroyer,

^ This. Also...

Your center of lift is too far behind your center of mass, so your elevators have insufficient leverage to get the nose up.

Your fuel supply is too far back as well as too little to get you to orbit and your payload is too far forward. When you get to orbit and jettison the payload, your spaceplane will probably be unflyable on reentry.

For a rough guide, check out this thread:

http://forum.kerbalspaceprogram.com/threads/133668-simple-rule-to-build-spaceplanes

Also, there are lots of good threads and tutorials on spaceplane design and construction. Also check the challenges, especially "Pro SSTO" and K-Prize. Lots of good starting points and ideas in there.

Best,

-Slashy

Yeah... it might help if I actually read stuff around here... Oops...

Also, you seem dreadfully short on oxidizer for the rocket part of the ascent and orbital maneuvering

I had a feeling that might be the case. I'm quite bad at judging how much oxidizer I need to bring for a SSTO...

Back to the drawing board I go!

[GoSlash27]

I love me some spaceplanes, but if I'm actually trying to build something in orbit, I'd rather just save the hassle and use a rocket tug. I like spaceplanes for personnel transfer though, that's just a simple rendezvous so I'm ok with being a victim of style for that.

^ I second this. As much of a fan as I am of spaceplanes, I never use spaceplanes to orbit "things", only "stuff". Physical objects like space station segments are really best handled by vertical lifters while supplies and kerbals (basically anything that can pass through a docking port) is a good mission for spaceplanes.

The reason for this is twofold:

1) You don't want to spend the time and energy to design and develop a spaceplane that you hardly ever use. Personnel transport and supply runs are flights that are done pretty often, while you will hardly ever need to orbit a chunk of space station.

2) Spaceplanes limit the size and shape of what they carry, which hampers your construction in orbit. Vertical lifters give you a way to lift whatever you want without limitations on mass, size, or shape.

Good luck!

-Slashy

[Nothalogh]

I had a feeling that might be the case. I'm quite bad at judging how much oxidizer I need to bring for a SSTO...

I would aim for enough to give me about 1600 to 2000dv in rocket mode.

As for liquid fuel for airbreathing mode, some like only enough for the ascent, but I like to have a little extra to give myself some wiggle room on landing

[Coga19000]

I third the rocket SSTO part. They are literally too easy to make ; a large 3.75 tank (maybe a medium one too), a Rhino engine and a crapload of chutes can get my stock stations in orbit in two launches (I'm mostly making USI-MKS stations though, which are overbuilt enough to need half a dozen launches, but still)