Flight Question How does one slow the DG-IV down enough for re entry?

[reconwarrior21]

I can launch the Delta Glider and establish (A pretty erratic, but somewhat stable) orbit around earth. However whenever I begin a deorbit burn, when It finished I spin it back around to have the nose pointed forward than raise the nose up to 40 degrees, however every time I hit the atmosphere the nose slams down and I break apart and burn up. Am I not slowing down enough, or am I not at the right angle? I tried to match it to the automated landing as best I could.

 

[Urwumpe]

Don't slow down too much! You need to reenter in an accurate corridor (-1.2° AFAIR). If you slow down too much, you reenter at a too steep angle: The dynamic pressure increases rapidly and you burn up.

Use the autopilot function for keeping AOA, not do it manually. The autopilot can do this much better. AFAIR, the autopilot also sets the trim of the spacecraft properly, while you would have to do that yourself for a manual reentry. Without proper trim, the RCS and the control surfaces can't keep the AOA up. Once you drop below 30° AOA, the aerodynamic forces on the wings will increase and will further force you down.

 

[reconwarrior21]

Thank you, though I have no idea how to use the auto pilot. I spend most of my time on orbiter launching rockets, and flinging ships into deep space (More or less on purpose.)

 

[Izack]

Thank you, though I have no idea how to use the auto pilot. I spend most of my time on orbiter launching rockets, and flinging ships into deep space (More or less on purpose.)

Happily, the DG-IV has an on-screen checklist and tutorial page, right next to the flight computer on the bottom panel. Screen 12 is what you're looking for, I think. It lists the various auto-pilot programs, usually PRO###SPEC###, entered in the keypad on the panel.

 

[Ripley]

Read this:
http://orbiter-forum.com/showthread.php?t=18671

It's a bit more detailed than requested, but there you can learn the basics (and much more).

Or watch this:
[ame="http://www.vimeo.com/4987103"]DeltaGliderIV reentry tutorial on Vimeo[/ame]

 

[statickid]

Try starting with circular 250-350 km altitude, lower your periapsis to about 60 km. This will pretty much guarantee a reentry interface glideslope of less than 2 degrees. Then press alt 7. If you're just starting out, you probably won't be able to do manual reentry because there is no manual center of gravity control in the dg-iv making it extremely difficult. The xr-1 (Altea DG) has cog shift.

Ps- if auto pilot does not engage, clear the reentry checklist

Pss - you might have to control the bank angle. Use 4 and 6 (IIRC) to change bank angle after auto pilot has engaged. Use bank to subtract lift or control cross range

 

[Ripley]

Reconwarrior21, are you speaking about the stock/default DeltaGlider, or Dansteph's DeltaGlider (DGIV-3)?
...just a thought...

 

[worir1]

Danstephs DG-IV has an auto pilot that you can see on the 2D pannel (alt 7 i think) the stock DG is much harder to re-enter. you need to use RCS and elevator trim to keep the AoA constant. I recommend no timewarp below 90km maximum. Once you have lost your AoA your lift will become too high and it is very hard to recover so try keep it as still as possible.

 

[statickid]

Reconwarrior21, are you speaking about the stock/default DeltaGlider, or Dansteph's DeltaGlider (DGIV-3)?
...just a thought...

the OP says dgiv

 

[ADSWNJ]

Earth reentry is darn hard to do, so there's no disgrace in failing spectacularly more than a few times as you get the hang of it. Ironically, and counter-intuitively, doing some take-offs and landings from Brighton Beach on the Moon is a better place to start because you can have a go manipulating your periapsis and controlling descent on gentle hover thrusters without having to worry about any atmosphere.


When you are ready to hit the Earth again, then statickid's advice is good above. Also you could look at my Glideslope 2 addon and tutorials in the docs for that addon. Lots of things to try in there.

 

[reconwarrior21]

Thanks for the help guys. Though my problem in low gravity is applying too much hover thrust and boosting myself back into orbit. I will be trying my hand at low gravity space flights now.