Realistic spaceshuttle re-entry with FAR.

[Vaporized Steel]

Hi boys and girls.

For the past couple of weeks in the few available hours I had I've been working on a seemingly realistic spaceshuttle. Using stock, B9, procedural dynamics and procedural parts.

I even made a seemingly realistic looking STS launcher analog.

I had big obstacles in actually making the launcher work in the first place by getting the center of thrust right and choosing the right action groups on my engines and all that kind of stuff.

Heres a pic of the shuttle I originally made Click

I had major problems with the old shuttle in terms of re-entry. And simply put I couldn't re-enter the thing at all.

So I build a new one that actually can do a re-entry. Here are 2 pictures.

Click 1

Click 2

And a third picture that shows center of lift, thrust and mass. Click 3

The shuttle flies perfectly, lands perfectly, handles perfectly, and actually lands with a high AoA just like the real spaceshuttle. This version is ofcourse the KSP STS analog on steroids as it has radial turbofan jumpjet engines to Ensure total aircraft capabilities.

The problem(s)

Problem 1:Even although it can re-enter the atmosphere it can only do so under the condition that it skips the atmosphere with a high AoA. This ofcourse is pretty realistic. The real spaceshuttle had to do so aswell. That's what sets aside capsules from spaceplanes. The former you aim in near uncontrolled fashion through a safe trajectory to aerobrake. The later (a shuttle) needs to control her Aerobrake maneouvre.

The main reason for my KSP shuttle to control the re-entry is because if I go in to steep aerodynamic forces (FAR) brake my shuttle and usually spins here out of control. As long as I do a re-entry with a static 15degrees nose up AoA all goes fine.

Question?: So how do I now aim for the KSC? Because I have to control my Aerobrake it can sometimes take 3/4 quarter of Kerbins circumference before I get into the lower atmosphere after actually entering the atmosphere itself. It will be vital to me that there is a way for me to construct a re-entry procedure that ensures I'll Always land near the ksc. With near I actually mean within like 100-200km. Remember it has jet engines to keep her going.

Problem 2: The 2nd major problem is my shuttles tendency to lose control in the upper atmosphere. When I said to re-enter with a AoA of +15 it doesn't just mean that there is a threshold below that descend plan for my control surfaces to brake from the fuselage. But for some reason my shuttle has the tendancy of pitchting, rolling perhaps even yawing in random directions after passing through 35km altitude. And the greater my speed at even lower altitudes mean that I get to a threshold where the shuttle cannot be further controlled and brakes into pieces the moment it flips over. Unless I keep her skipping the atmosphere so I miss that threshold. But even staying within the safe zone the shuttle just wobbles up and down and banks side to side. Sometimes banks (wobbles) from 30 degrees left to 30degrees right just in a matter of 2 seconds if not less in a continues fashion.

Only after decending through 6 km altitude the wobbling and pitching stops altogether.

If turning sas and/or ass off she just points wherever she wants to and changes her mind at any moment she wishes.

Manual input is actually worse then letting Smart A.S.S. take control of the descent. And whenever I tell A.S.S. to turn prograde or control a heading with a pitch up and I get to low in the atmosphere to fast it cannot even control the descent prior to failure.

A.S.S. does best jut by wobbling the shuttle in the proper direction while it is able to.

You got pictures of the shuttle. The small control surface just under/behind the central lower engine is for pitch. The 2 control surfaces on the B9 wing (SW Winglets) are also for pitch. The B9 control surface next to that (SE 1m) is for both roll and pitch. And the stock outer control surface (delta deluxe winglet) is for roll only. The center tailfin made from 2 procedural wing surfaces and a procedural control surface is for yaw (Obviously)

All the parts have been symmetrically attached in the spaceplane hangar.

I'm posting this because I need help after having spent to much effort, for to long without getting the damn shuttle to work. Atleast not in flight capabilities I so far desire.

I know that creating a spaceshuttle is pretty hardcore. Even more so if you want to make it look any close to a real life STS. I'm not expecting answers straight of the black/smartboard.

Rebuilding it over and over again might eventually present a usefull design. But after all this time I can't get my brain straightened out on all the possible modifications. So simply your Obvious suggestions might be fruitfull.

NOTE: I know there is a realistic STS package mod out there. Just in case you try suggesting that to me. It's not part of the challenge which is what I want. I want to build one without a pre packaged model.

I hope I can get the help I need.

Edited May 31, 2014 by Vaporized Steel

[Hodo]

For re-entry on all of my space planes I usually aim my PE marker about half way across the continent where the KSC is at. This way if I am short the craft can fly the rest of the way there under its own power, and if I am long I actually end up right at the KSC.

On re-entry I usually dip down to 20-25km PE to really slow down, I use DRE along with FAR so I understand the challenges. But I also never let the AoA pass 12.5deg to keep the craft from spinning. The AoA is the most important thing when re-entering the atmosphere, to steep and your craft will flip and blow apart, to shallow and you will dive into the atmosphere like a meteor.

[Vaporized Steel]

I'm indeed figuring the proper deorbit burn by trial and error to see where to deorbit burn untill I can manage a deorbit plan that will get me close to KSC. It's extra challenging because I am gliding (skipping) the atmosphere so it's a whole lot trickier then deorbiting a non spaceplane. It's not that I never deorbited a spaceplane before and not landed it near the ksc. But in the case of the spaceshuttle it's a whole lot trickier since the B9 cockpit and the B9 cargo bay have so little drag with FAR and your basically in a atmospheric decent halfway around the globe.

Do remember that my shuttle Always flies in a uncontrolled wobbly fashion. Even while I'm keeping the AoA high enough for a non fatal atmospheric decent. I want to get rid of most if not all the wobbling regardless of wether I get the shuttle on the ground.

Edited May 31, 2014 by Vaporized Steel

[Jimbimbibble]

Have you checked the CoM with tanks empty? It may have shifted in flight as you burn fuel.