Balancing a shuttle

[Pixel of Life]

I built this orbiter:

Now, I'd like to launch it like a Space Shuttle - that is, with a large external tank mounted to the bottom of the orbiter. The problem is, I can't really get the thing balanced with the tank attached, and it always flips at some point during the ascent. My question is, how would I balance it? Should I put a more powerful, decouplable engine under the orbiter's main engine and feed fuel from the external tank into it? I'd imagine using a counterweight is not the best option since it lowers the TWR of the craft.

[lyndonguitar]

There has been lots of recent topics regarding this matter, Try to look for them, they should not be that far away, they have great suggestions on how. and it's hard to do

[EndlessWaves]

You need to prevent the centre of mass moving horizontally, the simplest way to do this is to drain each fuel tank (shuttle and booster) at the same time proportionally to their total capacity.

[Tex_NL]

I 'borrowed' your design and build a very similar looking shuttle. Mine works perfectly so your basic design should be able to fly.

How did I do it:

1: I build the shuttle in the SPH and went for a test flight.

2: Exported the shuttle from SPH to VAB. (.craft copy/save)

3: Added boost stages in VAB.

4: Launch to orbit.

After flight balancing in step 1 step 4 can be tricky. Form experience I've learned to launch shuttles flying 'knife-edge' (e.g. one wing pointing up, the other pointing down) instead of level flight. Flying knife-edge causes the wings to loose their lift and no longer interfere with the launch path.

[sal_vager]

KSP doesn't really support Space Shuttle style launches, sorry, there simply isn't enough gimballing in the engines and there isn't the throttle control we need.

It can be done as I've seen it, but it's usually an ugly hack with extra engines hidden on the main tank or a counterweight of some kind.

[rryy]

You could modify an engine part, or make a new one, that has a large gimbal range, like 10. This will make a lot of wobble if the rocket is not stable, though.

[Nibb31]

Why not launch with a second orbiter on the opposite side of the rocket?

[Hovis]

Why not launch with a second orbiter on the opposite side of the rocket?

Damn you, I was reading along this thread thinking the same thing and you beat me to the reply.

And extremely powerful core rocket, two shuttles, one on each side. Might just be crazy enough to work.

[Tex_NL]

KSP doesn't really support Space Shuttle style launches, sorry, there simply isn't enough gimballing in the engines and there isn't the throttle control we need.

It can be done as I've seen it, but it's usually an ugly hack with extra engines hidden on the main tank or a counterweight of some kind.

It might not support shuttle style launches. But it can handle Hermes Style launches with ease.

Hermes, canceled like many great ideas, was designed to ride on the top of an Ariane V rocket. Korhonen's small orbiter (and mine) is ideal for this.

Why not launch with a second orbiter on the opposite side of the rocket?

That is possible but that way you'll be hauling a lot more mass into orbit then you need. Instead of strapping another orbiter to the other side of the rocket it makes more sense to sandwich the orbiter between two rockets.

Edited May 11, 2013 by Tex_NL

[bs1110101]

I kinda cheat with my shuttles and add the tiberdyne shuttle plugin on the engines i'm using, but you cant say it doesn't look good.

btw, can i have a .craft?

[Tex_NL]

...

btw, can i have a .craft?

You honestly need a .craft to copy such a basic vessel? It's not much more than a cockpit, crew- and fueltank, engine and a few wings.

[bs1110101]

nope, but it's rather hard to build the exactly the same thing when i have FAR and TV aerospace

also, i can't see where it's engine is

and as i guessed, something that short flips out with FAR

Edited May 13, 2013 by bs1110101