Chutes too hot?

[rdwulfe]

Is anyone else having this problem? I'm being VERY conservative with my reentry profile, but my chutes are too hot/the capsule is going too fast for my chutes to deploy. It instantly destroys them, every time. They're around 400 degrees. This is with an orbit barely above 70km when I do my reentry burn.

Any thoughts?

EDIT: Ah. The chute is the Mk16

Edited June 30, 2015 by rdwulfe

[clivman]

Deploy later? Below 250 m/s

[rdwulfe]

It remains unsafe to do so... and if you deploy that late, the chute doesn't open in time anyway. (Or didn't since 1.0 to my knowledge). The chute itself says 'Unsafe' the entire way down. And I just did another reentry, this time slowing myself to only 1,000 m/s before rentry, and still it remained unsafe. However, above 35km the chute said 'risky'. Both Val and Jeb are stuck in space currently. Wheee!

[clivman]

It remains unsafe to do so... and if you deploy that late, the chute doesn't open in time anyway. (Or didn't since 1.0 to my knowledge). The chute itself says 'Unsafe' the entire way down. And I just did another reentry, this time slowing myself to only 1,000 m/s before rentry, and still it remained unsafe. However, above 35km the chute said 'risky'. Both Val and Jeb are stuck in space currently. Wheee!

If you are under 250 m/s it will be safe to open and will open in time.

Edit: also, reentry profile has nothing to do with chutes.

[maltesh]

It remains unsafe to do so... and if you deploy that late, the chute doesn't open in time anyway. (Or didn't since 1.0 to my knowledge). The chute itself says 'Unsafe' the entire way down. And I just did another reentry, this time slowing myself to only 1,000 m/s before rentry, and still it remained unsafe. However, above 35km the chute said 'risky'. Both Val and Jeb are stuck in space currently. Wheee!

This has not been my experience, in general.

I just threw a 3-man Pod to Kerbin from the altitude of Minmus, and entered the atmosphere moving faster than 3km/s, and re-entered with an initial periapse of 25 km. Slowed to less than 250 m/s at 10 km or so, and opened the chutes without issue. No heat shield, and did get a single temperature bar onm the pod, but the chutes never got anywhere near overheating.

[mikegarrison]

My main chutes always say "safe" when the speed is under about 250ish. The drogue chutes say "safe" earlier than that. Unless you have a very unusual craft (like the infamous "rods from God" weapon), air drag should get you down to those kinds of speeds.

[rdwulfe]

Hmnh. I just managed to get the chute to deploy. I had to keep my second to last stage connected, to keep things from getting too hot, apparently. The chute would be destroyed and it actually told me 'chute destroyed due to heat/too much airspeed'. Wish it would specify which, especially considering these are *new* conditions we're dealing with. I LIKE how the chutes aren't all-powerful now.... Just gonna need some redesigning, apparently. The capsule I'm using is the K2_Command Pod. I'll have to test to see if the old pods have the same problem for me on my current setup.

[Lupus Irae]

I had that issue on a craft. What I did was have a more shallow (?) re-entry. Um. That is, I reduced my Pe. by a very small amount (to 68 some KM from a low Kerbin orbit of 70-ish), instead of a larger amount. Granted, that was because of a design flaw (very shallow margin for error) that left me with only a handfull of delta-v once I got into orbit.

This has worked twice, but I am not sure that it will be effective on other craft.

[Dangerous_Beans]

what periapse are you using on re-entry?

you want to be aero-braking by going horizontally through the atmosphere, if you have the periapse too low you will have too steep a re-entry trajectory and end up going too fast too low.

[rdwulfe]

Periapsis around 30km

[Dangerous_Beans]

weird, 30km should be ok. try Lupus Irae's suggestion, and just graze the atmosphere a few times.

another suggestion, since it's a part from a mod, try updating the mod. the version you are using might have weird settings that don't work with the current aerodynamics.

[rdwulfe]

IT's the most updated version of the mod. I think the factor is the decreased drag in 1.0.4. The command module and heatshield's drag isn't enough to slow it below 300 m/s or so. I'm trying a few different reentry profiles more. (This one has the periapsis at 50km I'm doing right now. If this doesn't do it, I'm going to send up a rescue craft, I guess. Or a special ship designed to dorbit and shield this (like my recovery craft I built to do some contracts.)

Makes me wonder how my other designs will fare,too.

[Korizan]

I don't open my chutes till I am 10K or lower. I would really love a screen shot of your re-entry angle and speed cause I have never even came close to having issues of landing a Pod and a heat shield back on Kerban.

[Mister Kerman]

I have this problem too. I'll have a normal heatshield/pod/inline placed parachute design, and half the time the parachute prematurely overheats and deploys, and half the time it works fine.

I generally aim for 70K Apo and lately 40K Per because 50K Per takes a little long for my tastes (coupled with my seemingly random success/failure.)

I can't seem to find an approach that isn't a coin toss.

As long as I can make it past atmospheric heating everything is fine and I land safely. I just find I lose my parachute a lot of the time before I make it to a slow enough velocity to deploy it.

[tutike2000]

Screenshot of craft, reentry angle, F12 debug menu of your chute getting hot would help

[Sharpy]

1. Leave it at 48km.

2. Try not to be too aerodynamic about the entry. Definitely not the sharp end of the capsule first.If your reentry vehicle is a long tube, try entering sideways; if you can't, wobble around not to dart like an arrow straight ahead.

3. The chute temperature has nothing to do with safety to open. The speed does. Sure if you burn your chute away, it's lost but anything short of filling up the heat bar has no impact on its performance and safety to open. 250m/s and you can deploy them.

4. You have to try pretty hard to get a single capsule not to reach the safe 250m/s. But if you have other things attached - fuel tanks, engines etc, this may be much harder, especially if it forms aerodynamic shape.

5. Also, don't aim for the mountains. The capsule usually slows down to the safe speed only around 3000-4000m, sometimes even lower. Even 300m is enough for the chutes to slow you down to the single-digit speeds from their 250m/s, but if you're aiming at a mountain of 3000m, you may not reach the 250m/s in time.

6. Get Airbrakes. They work fine at all altitudes, 60km is the right altitude to deploy them.