Reentry problems with the DG-IV
- Thread starter sethhope
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Izack
Non sequitur
Somewhere over the East coast of Australia is a fair bet. Trial and error will eventually get you to wheelstop at the SLC. But there people far more qualified than me to tutor you (haven't done this for half a year.) There are tools to help you, as well. AerobrakeMFD is supposedly invaluable though I've never tried it. It has glowing reviews.
insanity
Blastronaut
Aerobrake MFD is a great tool. There are loads of tutorials on this site that can help you get a good dead-stick landing using it, too!
Wishbone
Clueless developer
A reminder on Aerobrake: use version 0.95 since 0.96 is bugged in that it doesn't show the predicted landing point. Also Aerobrake relies on constant pitch/bank angles throughout the reentry, so you may want to complement it with Glideslope MFD which gives a bit more cues as far as energy profile goes. And practice, practice, practice.
Carmen A
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Since the DG has so much fuel, you might want to do a powered re-entry instead. How? Firefly style burn hover thrust when contacting atmosphere? Nope can;t do that.
But you can swoop down with the nose pointed 60 degrees to the horizon, fire hover thrust to both shave off a few km/s of speed and reduce the descent rate, and when you drop below 70km alt, you're able to transition immediately to scram flight. Less fiery stuff, more Firefly style action
The reduced re-entry speed means more chance for you to get used to the feel of controlling the craft in aerobraking mode (I like to keep the nose pointed almost vertical and it can reduce heat buildup on the nose and wings) without blowing up.
But you can swoop down with the nose pointed 60 degrees to the horizon, fire hover thrust to both shave off a few km/s of speed and reduce the descent rate, and when you drop below 70km alt, you're able to transition immediately to scram flight. Less fiery stuff, more Firefly style action
The reduced re-entry speed means more chance for you to get used to the feel of controlling the craft in aerobraking mode (I like to keep the nose pointed almost vertical and it can reduce heat buildup on the nose and wings) without blowing up.
Axertan
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But you can swoop down with the nose pointed 60 degrees to the horizon, fire hover thrust to both shave off a few km/s of speed and reduce the descent rate, and when you drop below 70km alt, you're able to transition immediately to scram flight. Less fiery stuff, more Firefly style action
Firefly-style flying is always a great idea, but what if person flies his beloved DG on expert settings?
Anyway, as has been said, Aerobrake MFD and Glideslope MFD are great tools, I learned how to fly down the atmo with those. The DGIV's automatic reentry program gets you down in a no-burn up fashion, and will get you down rather close to the AerobrakeMFD's target. (depending on what you consider close)
Once you get the hang of it, you'll be doing it manually, or with the half-automatic DGIV's autopilot in no time!
The great conclusion: Practice makes perfect. Dont give up now!
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Carmen A
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Expert settings? Be an expert first 
Urwumpe
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Don't forget to fly S-Turns, by keeping AOA constant, and bank to the side. The DG-IV autopilot permits such banks with some annoying limitation (maximal 60° bank angle), but it works.
Flying S-Turns permits you to slow down faster, than a full lift reentry, by dropping deeper into the atmosphere without quickly gaining altitude again (skipping).
The simplistic algorithm to follow there: Start reentry at full lift. When vertical speed is nearing zero, back in direction of your target (or any direction), until you are slowly descending. At this point, you should also reach the highest temperatures on a good reentry. The faster you descend, the hotter you will get. If you keep constant altitude, you will quickly cool down. If you keep constant deceleration, you will slowly cool down (because deceleration depends on dynamic pressure, and heating is dynamic pressure multiplied by speed and if you keep dynamic pressure constant for constant deceleration, velocity will drop at constant rate).
Flying S-Turns permits you to slow down faster, than a full lift reentry, by dropping deeper into the atmosphere without quickly gaining altitude again (skipping).
The simplistic algorithm to follow there: Start reentry at full lift. When vertical speed is nearing zero, back in direction of your target (or any direction), until you are slowly descending. At this point, you should also reach the highest temperatures on a good reentry. The faster you descend, the hotter you will get. If you keep constant altitude, you will quickly cool down. If you keep constant deceleration, you will slowly cool down (because deceleration depends on dynamic pressure, and heating is dynamic pressure multiplied by speed and if you keep dynamic pressure constant for constant deceleration, velocity will drop at constant rate).
Thank you, I will try this.
Ripley
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Mantis
Member
BINGO! That tutorial did the trick for me. I followed it to the letter and managed the feat on my very first attempt.:thumbup:
Grover
Saturn V Misfire
thats my tutorial! yay!
glad i could help fellas
glad i could help fellas
Mantis
Member
It was a HUGE help Grover! Thank-you very much. Prior to following your tutorial, there was no telling where I would end up if I safely reached the ground in a winged spacecraft at all. I have landed Delta Gliders anywhere from The Canadian Arctic to the middle of the Pacific! I did somewhat better with capsule re-entries in that I always made it down safely but I wasn't all that accurate about where I landed. I could never master it with winged spacecraft though. I printed your tutorial, sat down and tried it and managed to put her down on the Shuttle Runway at KSC on my first try. I made a few mistakes and it wasn't pretty but it was a LOT better than anything that I had managed before. I just need some more practice to get good at it!
I found that I did really well untill that transition between pure energy management and actually flying to the runway. When I hit Mach 6, I was still about at around 40,000 meters and almost right over the runway. I tried to do a HAC which was mostly successful but I found that by the time I completed it, I had depleted too much energy and I had to hit the engines a few times to allow me to reach the runway. Aside from those minor glitches (which I'm sure are just due to my inepxerience) I'm thrilled with the result and quite pumped up over it!
I found that I did really well untill that transition between pure energy management and actually flying to the runway. When I hit Mach 6, I was still about at around 40,000 meters and almost right over the runway. I tried to do a HAC which was mostly successful but I found that by the time I completed it, I had depleted too much energy and I had to hit the engines a few times to allow me to reach the runway. Aside from those minor glitches (which I'm sure are just due to my inepxerience) I'm thrilled with the result and quite pumped up over it!
Grover
Saturn V Misfire
with experience, you'll notice any errors you make nice and early, even if you've already made them, then you can correct them, by either turning to bleed off speed, or in the worst case, forcing yourself back out of the atmosphere and back up to orbit (just pitch down and pick up some positive vertical speed, then ride out of the atmosphere and use a little fuel to stabilise it, then spawn and launch another spaceship to fly a rescue mission )
well done, and keep at it, you'll be nailing the runway every time with a little practice
)well done, and keep at it, you'll be nailing the runway every time with a little practice
Mantis
Member
Practice indeed! I just did my second successful re-entry and landing at KSC in a row! This time, I took of from KSC, flew to the moon, entered lunar orbit, landed at Brighton Beach using the LOLA auto pilot, took off again manually, returned to LEO and hten did a successful entry and landing at KSC! Amazing. I can't believe how easy it is once you know how to do it. My second approach and landing was much better than the first. This time I approached from the southwest and with a little bit of an engine assist, managed to line up perfectly with the SLF runway and landed.
Grover
Saturn V Misfire
yea, and that technique can easily be changed for other craft, right now for example, im playing with the XR5, working out its own descent speed, angle and anticipation, then just put the new numbers into basesync.
and by chance, the DGIV and XR2 use the same valuse
and by chance, the DGIV and XR2 use the same valuse
