reenter in earth with dgiv

[bemanos]

hmm ok thanx for replies . i got one more question but i dont want to open a new thread. when i iam in orbit with dgiv how can i grab the turbo packs. i mean when i got one austronaut out he can only move left right up down and bank. he cant go forward or backward and i cannot grap the turbopack which is far away from austronaut

 

[IthyStPete]

Numpad 9 and 6 move forward and backward when you're in translation RCS.

 

[bemanos]

found it, thanx

 

[MJR]

There is a weight that you have to re-enter Earth at. I am not so sire about what it is though. What is you vertical speed and IAS during entry?

 

[bemanos]

thanx for all help. i think that i have mastered basic reentry now. thanx

 

[MJR]

It'll take a lot more to master re-entry. Just keep practicing and you will get experienced to the point where re-entry is just like getting into orbit.

 

[PaulG]

I'd like to add something to this for comments. When deorbiting from the ISS altitude, I deorbit opposite KSCX and monitor the reentry angle to about 0.8 degrees. This puts my altitude at KSCX to about 40km or so.

I generally hold my AOA at 25-35 °, moreso on the lower angle of 25°. I do bank and adjust the AOA to keep the predicted landing spot over KSCX. Once I start to approach 35km altitude, I continue to band and adjust AOA for final approach. Recently, I target 25km altitude at 10-15 km from KSCX aligning to the 145° radial for approach on runway 15 (I believe its 15). At that point, I'm traveling around 300-450 m/s and airbrake for final approach. Its a little steep, but does the job.

What are your thoughts on that? I have consistently landed well with the approach above, but never do I use a 40° AOA as has been suggested by every post out there.

 

[Ark]

I just use the aerobrake MFD's AOA function. Adjust your attitude to the right AOA before you hit the atmosphere and push the AOA button on the MFD. Then, chill while it brings you down to within spitting distance of your target base.

 

[PaulG]

I'm sure you are talking about the AOA on aerobrake MFD. But, I'm referring to the autopilot, PRO105SPEC40. Even when following the tutorial, leaving it up to the autopilot does not produce an endpoint near the base. Effectively, a much lower AOA is needed. Just wondering why 40 (30-45) is often suggested, as it is not what I have experienced given the conditions above.

 

[Tommy]

If you read the scenario header and manual, you will see where the de-orbit burn should take place when using p105, and it's not 180 degrees from the target. IIRC it's around 14.4M.

As stated in the DGIV manual, P105 isn't concerned with a target, it simply maintains a safe decent rate. Where you de-orbit will determine where you land, and your orbit's altitude determines how far ahead of the target you should de-orbit.

De-orbiting opposite the base makes for a long, gentle re-entry, and an AoA in the 30 to 35 degree range is needed to get the extra range required. The DGIV is designed to be de-orbited closer to the target, and the 40 degree AoA will bring you down quicker, but makes heat management more critical.

 

[Ark]

I'm sure you are talking about the AOA on aerobrake MFD. But, I'm referring to the autopilot, PRO105SPEC40. Even when following the tutorial, leaving it up to the autopilot does not produce an endpoint near the base. Effectively, a much lower AOA is needed. Just wondering why 40 (30-45) is often suggested, as it is not what I have experienced given the conditions above.

I don't like using that, it locks you into that AOA the whole way down, when really you need to change it at some point to get you closer to the base. It's fine for holding AOA during the heavy reentry, but you have to get pretty lucky to actually arrive on target using the DGIV's autopilot.

 

[Tommy]

I don't like using that, it locks you into that AOA the whole way down

Actually, the angle given in the SPEC is ignored, and the AP adjusts the AoA as needed to maintain a constant decent speed. I don't like it either, in order to hit a target you need to be perfectly aligned (PRO105 won't bank to correct heading), de-orbit at just the right time and use just the right ReA (both will vary depending on altitude of current orbit). PRO104 allows the pilot to determine the AoA and bank, and combined with AerobrakeMFD, makes spot-on re-entries reasonably easy.

 

[PaulG]

If you read the scenario header and manual, you will see where the de-orbit burn should take place when using p105, and it's not 180 degrees from the target. IIRC it's around 14.4M.

Hmm..perhaps that is why I have been confused the[FONT=Verdana,Geneva,Arial,Helvetica,sans-serif]Autopilot Automatic Reentry tutorial scenario said [/FONT][FONT=Verdana,Geneva,Arial,Helvetica,sans-serif]"[perform deorbit burn] at 17.20M from the cape until your reentry angle show 1.200° [/FONT]

De-orbiting opposite the base makes for a long, gentle re-entry, and an AoA in the 30 to 35 degree range is needed to get the extra range required. The DGIV is designed to be de-orbited closer to the target, and the 40 degree AoA will bring you down quicker, but makes heat management more critical.

AH....so, at 180° from the base and a re-entry angle of 0.8 °, the AOA I've noticing is reasonable. I'll have to try it a bit closer and with 40 °, and apply a little of the Goofy Holler.

 

[Tommy]

Hmm..perhaps that is why I have been confused the[FONT=Verdana,Geneva,Arial,Helvetica,sans-serif]Autopilot Automatic Reentry tutorial scenario said [/FONT][FONT=Verdana,Geneva,Arial,Helvetica,sans-serif]"[perform deorbit burn] at 17.20M from the cape until your reentry angle show 1.200°[/FONT]

I wasn't at home when I made the previous post, and my memory failed me - 17.20 is correct. I usually de-orbit the DGIV a bit closer, but sometimes farther when I want a less stressful re-entry.

And yes, de-orbiting earlier with a shallower ReA will require a lower AoA during re-entry to get the range needed. Try it at 17.5 M with the P104, and when you master that, start closing in. The closer you get the higher your ReA will need to be. With no Cargo and very minimal fuel, you can de-orbit 6M from target using a 6 degree ReA, and deadstick the landing once you get the hang of it.

 

[insanity]

When I'm base-aligned in the DGIV I fly the p104s40 autopilot. It allows control of the descent and aerobrake mfd dictates the change in bank angle. With a bit of practice you can kiss the runway's center line without firing the engines once. It is a great feeling the first time you do it and it gives you an understanding of how to do it in other vessels.

 

[TMac3000]

ok so is there a more fast procces for a reentry? or must i use the 10x time wrap tool if i dont want to wait for hour (maby)

Patience, Grasshoper. Re-entry takes time, even when you use smart time-saving methods.

When you reach 150 km altitude, pitch up about 35 degrees on the pitch ladder. At around 70 km, you will start feeling the heat. Keep your vertical speed between -70 and -90 m/s, and don't let the nose temp get above 1600 degrees.

I ran into the problem with the nose falling too. Solution: When you have the stick all the way back and the nose is still falling, start using trim to keep it up, until the trim is all the way back. When the computer switches to atmospheric control, the nose will suddenly jump, so use forward stick to keep it between 35 and 45 degrees until your speed drops below Mach 2.5. Then zero out the trim, and have a safe flight back.