Flying the shuttle... how the kerbhell do you do it?

[Jimbodiah]

Ok, tried several ways to make it work, but this thing will not launch the way I do it. Tried to search on the forum, but all I see it shuttles modded in 50 different ways to make it work. Is there any way to get an actual realistic shuttle off the ground?

[sal_vager]

Yeah but it's a balancing act, at least it was in my attempt.

First I made the shuttle in the SPH, stuck some jets on it and made sure it was able to fly on its own.

Then I moved it to the VAB and added the external tank, no boosters yet, and after lots of tweaking made sure it could fly without flipping out with a near empty tank, depending on your engines you may need to hack gravity for this.

Then I added the boosters, a big bunch of 10 long SRBs on each side, taking care to balance thrust between them and the shuttle with a full fuel tank.

After that it was lots of test flights and tweaking of the boosters to get them to burn out in batches without the thrust being too high or too low for the main engines to compensate, I still had to manage the throttle to avoid overpowering the SRBs at some stages of the flight, but it was manageable.

Lots of work just to avoid vernor or reaction wheel spam, and it's only capable of fixed payloads so I had to make a bunch with slightly different engine rotations to cope with different loads, I really should see what it can do with Vectors ...

I'll see if I can find the post in What did you do in KSP today? and link it.

Edit:

Can't find the post, forum search seems about the same as in vb, but here's the shuttles.zip so you can take a look.

[InterCity]

It depends on how your shuttle is made.

If it`s a STS-like thing (Main engines on the orbiter, some SRBs at the sides), then you're probably going to have a bad time. Those are absolute pain to fly in KSP, due to the way the game's physics work. You'll need to align your thrust with the centre of mass of the whole shuttle assembly (at all times!) and pray to the Kod or the Kraken or whatever entity is it that made kerbals that it doesn't shift itself too much.

If you used the Buran-like approach (Essentially a spaceplane strapped to a giant rocket - engine under auxiliary tank), you should be relatively fine - albeit it's still a major pain in your rear on takeoff. In this case, you want to shift the SRBs slightly towards the orbiter (so that you have less torque from their thrust) and then you can control it by limiting the thrust of either the auxiliary engine or the orbiter engine. Usually you'll end up limiting the former because of CoM shift as the fuel gets burned (DO NOT FORGET FUEL LINES FROM AUX TANK TO THE ORBITER!!!!), but sometimes when your orbiter is carrying a hefty payload, you might actually want to limit the latter so it doesn't flip.

Either way, make sure that you have at least some engine aligned with the CoM of the orbiter (pointing the hollow end towards the rear), otherwise you'll be kinda boned when doing burns.

For re-entry, try to have a good landing zone (KSC for best results, the desert also works in case of emergency), because in my experience shuttle replicas tend to be quite nose-heavy when empty and thus need some speed to be landed.

Best luck with your shuttles!
 

[Jimbodiah]

I have the three main engines aligned with CoM, need to throttle them down until the whole things starts to lean back, then throttle up to keep it straight but not tip over. But after that the thing starts turning sideways and there is no holding it. They have all the parts and introduced the engines in 1.0.5, but basically you are unable to use them in a real shuttle simulation without resorting to improvised boosters etc. That is just funky and I wonder why they bothered with the special parts for the shuttle (slanted engine mount, new gimballing engines).

[GoSlash27]

Jimbodiah,

 STS designs are about the hardest thing to do in KSP. I fly mine by designing it to be perfectly balanced throughout the flight. This isn't easy. The engines must be set up so that they thrust through the CoG. The fuel flow must be set up so that the CoG naturally falls toward the engines as the fuel drains. Even the SRBs must be mounted a little offset so the total thrust is through the Com.

 The actual flying is weird because it flies "crooked". To roll, you use yaw. Any roll input will generate an unhappy yaw response. The Vector's wide gimballing range would *seem* to improve this behavior, but in reality it just makes it worse.

Good KSP STS replicas are do- able, but they're not easy to make or fly. A well- balanced shuttle is hard to fly. A poorly balanced shuttle is *impossible* to fly.

Best,

-Slashy

Edited December 5, 2015 by GoSlash27