General Question Shuttle Reentry

[Delta glider]

Now as the title tells you, I have been trying every technique I could come up with to reenter the Space Shuttle but either they are too unrealistic (I want a reentry like the real missions) or they miss the target or burn up. I am using Shuttle Fleet 4.8. Any help appreciated.


---------- Post added at 07:33 PM ---------- Previous post was at 07:30 PM ----------

(I can reentry using an AOA hold in XR vessels or the DGIV but as the shuttle doesn't have one I can't reenter)

 

[PhantomCruiser]

I just use AutoFCS. I can do a manual reentry but I'd hate to see what the g-load on the crew would do to them.

If you haven't already done so, watch what the autopilot does during AutoFCS. I usually (manually) find myself a bit too high and fast, I've more or less got it figured out...

The shuttle flies very well at hypersonic speeds, that's why just using an AOA hold causes you to porpoise so much. AOA slows you down, but it's the S-turns that keep you from bouncing back up. Rolling beyond 90 degrees is key. Watch AutoFCS and all will be revealed. Have SurfaceMFD up so you can watch how vertical acceleration changes with bank angle, the "light bulb" should come on for you.

 

[Delta glider]

No I understand banking and it stopping upwards lift so the shuttles vertical speed changes but how do you get Auto FCS? I did not see it in the modules tab after installing shuttle fleet 4.8. In fact, yes I can reenter it manually but as with you, I'd hate to see the G-load and the temperature.

 

[Cras]

You can use Glideslope MFD for its attitude hold and its steering program to help with S-Turns, or use AutoFCS. There is some work that needs to be done to get it to work in 2010p1 but it is all covered in the Shuttle Fleet manual.

 

[Delta glider]

No I understand banking and it stopping upwards lift so the shuttles vertical speed changes but how do you get Auto FCS? I did not see it in the modules tab after installing shuttle fleet 4.8.

Did you see this post Cras?

 

[Wolf]

Try this

https://dl.dropboxusercontent.com/u/66543113/AutoFCS2.zip

and then READ THIS to make it work with Orbiter2010

http://www.orbiter-forum.com/showthread.php?t=26263&highlight=autofcs

 

[Delta glider]

Thank you wolf.:thumbup:

 

[Cras]

Did you see this post Cras?

My bad I thought it was in the base SF package. It is not. It is in the expansion pack he released, it is covered in the manual there.

 

[Delta glider]

Oh, Its just that he does not metion it anywhere in the manual. :facepalm:

 

[PhantomCruiser]

I forgot who figured out that AutoFCS did work with Orbiter 2010, but once they did, the forum lit up pretty good. I think there's at least three threads dedicated to how to set it up, with associated comments.

Setting up the earth.cfg file for additional runways is pretty easy. And once I start the program and it does the initial de-orbit burn, I usually go take a break and come back 20 minutes later. I'll get back long before TAEM, then it's just a matter of waiting to drop the gear.

 

[Delta glider]

As a + to this - autoFCS doesn't show me how to do a S-turn reentry. Does anybody know easy ways to use them?

 

[PhantomCruiser]

Watch the map as AutoFCS does its thing. You will see the line curve left and right depending on the bank angle. If the shuttle is hard over in a left bank (say 100 degrees or so) the line will start pulling to the left (maybe as far as Jacksonville) it won't stay there long as she'll roll over to the opposite side and hold that for a while and the line will pull south again.

Pitch angle (AoA) will vary through the program as well, she may start out at 40 degrees, but will shallow out as the program progresses.

If you want to try it manually, you essentially do the same thing. Watch the map, and watch your speed, rate of descent, bank/pitch angles on SurfaceMFD. Most of your speed will bleed off around and altitude of 50-60 Km. I try to stay around 55. If you see that you are going to overshoot, roll just a bit beyond 90 (you've got back-stick in the whole time). If your s-turn is taking you too far off course roll the other way, keeping in mind when you do this you AoA will go wonky for a bit.

The only way to do it, is to do it. And keep practicing. If you don't do the s-turns, you can aim for KSC and skip all the way to Europe. AoA spoils airspeed and bank angle spoils lift. And whatever you do, don't use time compression. A typical re-entry (for me) takes about 30 minutes or so.

 

[Delta glider]

Well what I want is a Speed/Distance chart to get me to stop near KSC and thats all.

 

[IronRain]

Well what I want is a Speed/Distance chart to get me to stop near KSC and thats all.

Have you tried this MFD already?

You can use Glideslope MFD for its attitude hold and its steering program to help with S-Turns.

It basically gives you the info you need.

 

[Delta glider]

I find it difficult to understand the manual.

 

[Cras]

if all you want is a speed/distance chart then just use Aerobrake MFD, that shows you EXACTLY where you are gonna dump out at if you maintain your current attitude throughout the re-entry, and you can adjust accordingly. It will also show you EXACTLY what your altitude, speed, and the heat you will encounter throughout the deorbit, so you can adjust your attitude accordingly. The pages are pretty straightforward.

To deorbit Shuttle Fleet I use AutoFCS which does the deorbit OMS burn for you, does the EI attitude for you, does the S-Turns for you, it will fly the hack for you, it will fly the final for you, it will flare for you, touchdown for you, and brake the orbiter to a complete stop for you.

I never let it go that far, I kill AutoFCS before I get to TAEM and fly that part by hand leaving AutoFCS's flight director on as guidance, but mostly using Glideslope for the information I need to get to the runway.

Now what you need to do is look at the STS Payloads Expansion Pack manual, page 14, says what you need to do to get AutoFCS functioning in Orbiter 2010p1, it even has a screenshot of mshields original O-F post that showed us all the light. I really recommend reading the manuals David413s put together for Shuttle Fleet and the expansion pack because he clearly put a lot of effort into writing them and they are quite comprehensive, answers pretty much all the questions I see with regards to Shuttle Fleet.

Once you have AutoFCS up and running, you will see dropdown menus with the various bases you got in your scenario, and the runways, pick the ones you want, then just let it run and you will see it work its magic.

 

[Urwumpe]

Well what I want is a Speed/Distance chart to get me to stop near KSC and thats all.

Read the fantastic manual:

http://www.nasa.gov/centers/johnson/pdf/567069main_ENT_135_F.pdf

The information you are looking for is on page 29 in the PDF (Flight Supplement 4-9)

VR is relative velocity in kft/s
R is distance to KSC in NM
H is altitude in kft
H with dot is descent rate. in ft/s

Alpha ref is the AOA reference data: The first number is the high limit, the middle the estimated value (before flight), the third the low limit for the AOA.

The autopilot of the Shuttle does vary AOA for small rapid corrections of the trajectory and uses bank for the long term stabilization.

 

[Delta glider]

I do have AutoFCS up and running! No I can't use aerobrake because when I bank the path goes all over the place. I use BaseSync to see my cross-range. Do you know how find the specific distances from base for down-range and cross range?

 

[Cras]

Do you know how find the specific distances from base for down-range and cross range?

Glideslope 2, or Re-entry MFD, try those then, tells you both.

 

[Delta glider]

Ok then.