SWAFO wrote:
Is there a tutorial for the BaseSync MFD anywhere? The manual is a little hard to understand.
I'm not sure if it will help me. So far I'm having great success starting a retro burn over the western coast of
Australia (about 19.00M GOING TOWARDS SLF KSC) and getting my re-entry angle down to .75 degrees. Then, I
simply adjust AOA between 65-100KM to hit the target. Not the most precise method, but I usually end up around
the middle of FL.
BaseSync is a useful tool for deorbiting and reetry. Let's suppose you are flying a Detla Glider III in LEO (inc around
51 deg) and want to land in KSC.
1. Open BaseSync and press TGT. Enter 'Cape Canaveral' into the box. The site's name will show up in the upper part
of the MFD.
2. There are two major modes: Deorbit Program and Syncing mode. If you are not in the second, switch to it by DEO
(Shift-V). You should see a screen with a plot and three columns of numbers.
3. Switch to the closest passage mode if you're in Equatorial (E/D).
4. Note the three columns of numbers. Each line corresponds to your closest KSC passage at the given orbit loop, first
one is for the current loop, second line is for the next and so on. The left column is the time before passage, right is
heading in which target will be during passage, and the most important is the middle one. It shows you the distance
between your orbital plane and KSC. You would want to wait until one of the least values comes up for the current
loop. This way, your need for sideways manoevre becomes minimal. Minimum distance is highlighted.
5. Once you are on the correct loop for landing (highlighted value on the top), you may want to do azimuth correction
manoevre (just burn normal or anti-normal and watch if the landing site distance decreases - if not, flip your ship to
opposite position), or leave this part for aerobraking (espesially if you have no much fuel left).
6. Switch to Deorbit mode (DEO). Enter values: Reference altitude (ALT) 65 km, Reentry angle (ANG) 0.8, Reentry
anticipation (ANT) 25 degrees. Those are guess values I often use for landing from LEO.
7. Wait until green radius marking your position passes over a grey radius and do retrograge burn watching as BT
and dV value decreases to zero. Small errors, like few extra m/s dV are tolerable.
8. Now switch to Closest passage mode again. Bring Surface MFD on the other MFD and wait until you drop below 100
km altitude. Ensure your ship is rigged for reentry, which means that all radiators and antennae retracted, EVAs are
pulled in, hatches closed.
9. Engage reentry autopilot at 40 degrees pitch, and bring reentry heating display on a smaller DG3's instrument
screen to see how ship is heating up. With the autopilot, you can command pitching up and down in 5 deg step and
banking in 30 deg step. This is just enough to do a fine manual reentry.
10. Now turn all your attention to the two MFDs. On the surface MFD, watch Vspeed and Vacc (vertical speed and
vertical acceleration). To avoid burning up, your vspeed must not exceed -80 .. -100 m/s, usual value is -50 m/s.
Initially, you will descend much faster, but at 70 km altitude, lift will appear and will keep you from falling down. Your
task is to control vertical speed, not allowing it to drop too much. Positive v-speed is dangerous too, it's easy to send
your ship in uncontrollable bounce which will end either with overshooting your landing site or even worse burn-up at
the second reentry. So, don't allow your v-speed to rise above +20 m/s at all times. About Vacc: when it's around
zero, your descent rate is stable.
11. Look at BaseSync MFD again: There are Gsp and Dst values at upper left. Gsp is the ground speed, Dst is
distance from landing site in kilometers. Try the following check point table for reference (values are given roughly):
Distance Gr. Speed
3000 > 7000
2000 5800
1500 4700
1000 3200
700 2500
500 1800
300 1100
100 < 700, begin landing preparations
A rule of thumb: if you go too fast, dive deeper, as long as hull heating allowes. If you go too slow, dive slover or even rise a little bit.
12. If your lift becomes too great, there are two things you can do: increase your pitch angle or (better) bank to one
side to eliminate lift and do an S-turn. You can do S-turns deliberately at the begin of reentry, to line up with KSC
(watch middle value - sideways distance - in the closest passage screen again). Watch your Vspeed and Vacc on the
surface MFD at the same time. Banking 90 degrees give the best result in means of turning. Play with your pitch too.
13. Disable your reentry autopilot when the ship's hull begins to cool down quickly.
This technique can bring you withing 100 km range of the landing site, which you can easily cross using engines. You
may do a successful reentry at the first time, but keep trying, and you will catch the feeling and gain experience.
Good luck!
Post Edited ( 09-01-05 09:05 )
Search
Login
Register