how to build/ fly an SSTO

[jake9039]

I would love to build ssto's, but the problem is that I always run out of oxidizer and liquid fuel once in space. how do I get them efficiently(read: without hyperediting in fuel) into orbit, or is it just bad design. I always run out during circularization.

Edited March 19, 2015 by jake9039

[GoSlash27]

Jake9039,

Here's a good starting point:

http://forum.kerbalspaceprogram.com/threads/102182-So-you-want-to-build-a-space-plane-%28-25-stock%29

Still applies to .90.

Hit me up if you have any questions.

Best,

-Slashy

[Taki117]

You don't need as much Liquid fuel for your jets as you think. One 1.25m jet fuel tank should be fine for your jets. Another thing you want to consider is leveling out at about 10km to build horizontal speed. Most people say wait until 20km, but at that point there's not enough time to get your apoapsis up high enough before you start to run out of air at about 25km. Also, throttle back as your air gets low, and shut down engines you no longer need. The longer you can stay on jets the better.

[WanderingKid]

Your SSTO should only need 50-100 dV to circularize if you push it to the limits of the atmo (in stock). Either you're not carrying enough fuel (highly unlikely) or you're not building enough speed before you need your oxidizers. Might be a flight profile issue, might be a craft design issue. Hard to tell with so little description.

[FlyingPete]

You can get a single-pilot aircraft into orbit with a single jet fuel tank and engine, plus some RCS fuel. It all comes down to flying the right profile. Don't just aim for space as soon as your AP gets high enough. You should be skimming along in the atmosphere, building up speed and climbing relatively slowly. Towards the end, when you're suborbital, you should be pitching down slightly to keep within the atmosphere. The faster you go, the higher you can keep the jet engine running.

Edited March 15, 2015 by FlyingPete

[GoSlash27]

^ What he said.

Limit your climb rate to 200m/sec up to 20 km altitude.

Limit your climb rate to 100 m/sec up to 32 km altitude.

Limit your climb rate to 10m/sec up to 36 km altitude.

The idea is to let your turbojet do all the work and build speed. So long as you can hit 2,175m/sec ground speed at 36km, you will establish an apoapsis in space just from the speed. Circularizing from there doesn't take much.

This little guy demonstrates how little is needed to make it work.

These monsters are more practical examples of the same thing.

Best,

-Slashy

[Pecan]

A SSTO:

Stayputnik, small IRW, FL-T200, 48-7S.

For useful payloads, given the appropriate fuel and assuming 200m/s for de-orbit/landing, a T30 will SSTO approx 1.4t, a Skipper 5t, Mainsail 11t and KR-2L 26t. Other engines are possible but these are the simplest.

[Slam_Jones]

The middle area is the most important. Nacelle (with 40 units liquid fuel) and a T-800 tank is more than enough* dV to get you there. Slap a RAPIER on the back, toss in some wings and intakes, and you're good to go!

* I like to have about 500+ dV once I get to orbit for rendezvous and brute-force plane changes, and with this I usually end up with 900 - 1400 dV left, depending of flight profile.

Edited March 16, 2015 by Slam_Jones

[jake9039]

--snip-- Another thing you want to consider is leveling out at about 10km to build horizontal speed. Most people say wait until 20km, but at that point there's not enough time to get your apoapsis up high enough before you start to run out of air at about 25km.--snip--

this helpped me a lot. in fact, just yesterday, I just made it to orbit! and back!!! I gave Jeb 2 pre-death funerals, but he landed without damage. and I thought I might die from giant VAB because recently I had a minmus capsule falling apart from mun slingshot.

[Scarecrow88]

I've just built a fairly easy to fly SSTO that has limited cargo space for carrying small satellites to orbit. It doesn't have an over abundance of fuel, but with a standard SSTO flight profile it has enough to achieve a 100km Kerbin orbit.

The craft download file and more pictures can be seen here Blackbird SSTO exchange

Edited March 20, 2015 by Scarecrow88

[Mister Dilsby]

I would love to build ssto's, but the problem is that I always run out of oxidizer and liquid fuel once in space. how do I get them efficiently(read: without hyperediting in fuel) into orbit, or is it just bad design. I always run out during circularization.

You've seen some good advice and some very pretty ships--now get in that SPH! There is no substitute for trial and error. Build a ship that looks the way you want it to look, probably around a single jet engine to start. Concentrate on making the jet work first, that's the hard part. Do your best to fly a profile like the one Slashy cited. Then:

--Did you run out of air before you got to a good altitude? Add intakes, climb slower and build speed.

--Did you run out of jet fuel too early? Add more, or climb faster.

--Did you lose control of the ship? At what altitude? Try to simulate the conditions (fuel distribution, etc) in the SPH. Check your centers of mass, lift and thrust again.

Once you can tweak the above well enough to go about 1500 m/s at 20km or so, you can reach orbit with a good push from a rocket engine. The faster and higher you go, the less rocket you need.

And if you really want to learn spaceplane SSTO I would stay away from the RAPIER engine. Learning to balance your jets and rockets 'the hard way' will give you more real understanding.

See you at 70km!

ETA: I see you made it in a subsequent post. Well done!