Protecting radial parachutes with FAR and DRE installed

[zuuhis79]

Hello all.

I have installed DRE mod, and tried it for a little while now, as an addition to FAR, with which I have played for a lot longer. It makes things a lot harder in many occasions when returning to Kerbin atmosphere. The radial parachutes seem to explode no matter what I do, unless I install a significantly bigger heatshield compared to other ship (for example 1.25 meter ship with 2.5 meter heatshield). This of course causes the aerodynamic features of the ship to be less than optimal when flying upwards, because of FAR. Do you, who have more experience with DRE, have any good tips or examples on how to protect those radial parachutes from overheating during descent? Or do you use them at all?

Edited October 27, 2014 by zuuhis79

[The_Rocketeer]

What shape is the craft? Are we talking about a cylindrical rocket stage, a lander, spaceplane...?

One answer would be to keep the chutes on the sheltered side of the craft during re-entry, obviously requiring some careful pitch control. Or, depending how far you're willing to modify your design (and use parts for purposes other than directed), you could use something like a radial intake as a deflector part to protect the chutes.

[Taki117]

Assuming you are talking about a standard 1 man capsule you need to keep our radial parachutes as high up on the capsule as you can. However, because Stock Radial parachutes are so large this might not actually help. Since you use both FAR and DRE (As do I) I suggest adding Realchutes to your mod list. It changes how parachutes deploy, as well as allowing you to change the size of the parachute case, meaning that for a 1 man capsule you can have a smaller parachute case which will be better protected.

Another note when using DRE + FAR is to not deploy your parachutes when you are super sonic. Generally speaking don't deploy your chutes above 7km. I usually do semi-deploy at 3km and fully deploy at 500-700 meters.

[Starman4308]

If it's a manned capsule, I'll often put important things like parachutes on the slope of the manned capsule, tucked away from re-entry burn. DRE has caused me to find really interesting ways to tuck the goo pods on Stayputnik cores very close to centerline.

Other than that, though, a heatshield 0.25m wider than the rest of your craft should be more than enough to protect most things, at least if you're being careful not to deviate more than 5 degrees from surface retrograde. Procedural Parts has such heat shields. If you're worried about aerodynamics, I usually put a fairing over my capsule anyways, because even little things like batteries, parachutes, and solar panels are often more than enough to cause aerodynamic drag and instability in FAR*.

A picture of your reentry vehicle would help in diagnosing the problem.

*One thing I would recommend in order to get a sense of this is micro-rocketry: try to get a Stayputnik core with a token payload to orbit on the smallest rocket possible, which will make you really see aerodynamic issues. Despite putting only 6 OX-STAT solar panels, three batteries, a thermometer, an antenna, and a MechJeb case on the Stayputnik core, that was far more than enough to cause my 4 tonne rocket to swing wildly until I put a fairing over it (ballooning the mass to 6 tonnes, but what can you do?)

[Mystique]

Are your chutes (part itself) actually exploding or chute get cut? If 2nd, they it's fine - you need to deploy chutes while surface speed is subsonic, if 1st - craft's picture is needed.

P.S. Also ensure that you're using latest version of DRE, one of previous releases was quite rough due to experiment with settings.

[zuuhis79]

The chutes are really exploding. Here is an example of a spaceship's last stage when they explode:

https://www.dropbox.com/s/2gky9pdcu0w2ara/ship.png?dl=0

I think I have the latest version of DRE. Realchutes is a mod I might try. Also procedural parts seems a good idea, because those heatshields that come with DRE don't have adjustable sizes. I have used fairings with this, but with DRE heatshieds it means that my last stage will be 2.5 meters wide if I have a manned mission, and it is not wise if you think of the ships delta-v.

Anyway, thank you for these tips, and any other tips are welcome also!

[Taki117]

Anyway, thank you for these tips, and any other tips are welcome also!

Something else you might try is to move your parachutes from the sides of your lander can to the top of your lander can. This way the bottom takes the brunt of the reentry, leaving your parachutes safe. They will still deploy.

[Methusalem]

The most general response would be to keep the parachutes out of the air stream.

If you build a lander, mount them above the outer tanks/lab parts. If you have a standard cylindrical re-entry stage, then maybe use the Lander Can (the octagon shaped capsule) instead of the standard version. Then put the parachutes on top of the capsule. Maybe flip them and mount them vertically, that saves enough space that you can have 4 parachutes up there.

By the way, I've got the same issue with the landing gears, they always burnt up during re-entry. Now I actually stopped using them for the landers and simply land on the heat shields (which are needed anyway to protect the outer parts of the lander).

[Starman4308]

The chutes are really exploding. Here is an example of a spaceship's last stage when they explode:

https://www.dropbox.com/s/2gky9pdcu0w2ara/ship.png?dl=0

I think I have the latest version of DRE. Realchutes is a mod I might try. Also procedural parts seems a good idea, because those heatshields that come with DRE don't have adjustable sizes. I have used fairings with this, but with DRE heatshieds it means that my last stage will be 2.5 meters wide if I have a manned mission, and it is not wise if you think of the ships delta-v.

Anyway, thank you for these tips, and any other tips are welcome also!

Where's the heatshield? You might need a 2m heat shield (because the lander can would poke out from a 1.25m heatshield, and 1.5m might not be enough), but it generally helps to have a heatshield.

Also, I would suggest placing the goo pods on the top or bottom of the lander can so as to better tuck them in towards the centerline: if placed simply radially, they extend outwards uncomfortably far

[WeirdCulture]

The chutes are really exploding. Here is an example of a spaceship's last stage when they explode:

https://www.dropbox.com/s/2gky9pdcu0w2ara/ship.png?dl=0

I think I have the latest version of DRE. Realchutes is a mod I might try. Also procedural parts seems a good idea, because those heatshields that come with DRE don't have adjustable sizes. I have used fairings with this, but with DRE heatshieds it means that my last stage will be 2.5 meters wide if I have a manned mission, and it is not wise if you think of the ships delta-v.

Anyway, thank you for these tips, and any other tips are welcome also!

On the picture, you see that the chutes and the goo canisters are unshielded, so thats why the explode.

[Methusalem]

Where's the heatshield? You might need a 2m heat shield (because the lander can would poke out from a 1.25m heatshield, and 1.5m might not be enough), but it generally helps to have a heatshield.

He is probably using the engine as "heatshield". They are able to withstand the re-entry from a Kerbin orbit without blowing up. (The LV-909 can take up to 1800 celcius.) Although, if you come back from one of the moons, you probably want to get into an orbit first. Otherwise the velocity will be to high, which means too much heat and the engine will still get destroyed.

On the picture, you see that the chutes and the goo canisters are unshielded, so thats why the explode.

I would change it to something like this. Although, the module comes in at 2.200 kg, plus whatever is in the tank. The engine only survives an impact up to 8 m/s. It might need a third parachute (a normal Mk16 on top would do).

Edited October 27, 2014 by Methusalem

[tater]

The chutes are really exploding. Here is an example of a spaceship's last stage when they explode:

https://www.dropbox.com/s/2gky9pdcu0w2ara/ship.png?dl=0

I think I have the latest version of DRE. Realchutes is a mod I might try. Also procedural parts seems a good idea, because those heatshields that come with DRE don't have adjustable sizes. I have used fairings with this, but with DRE heatshieds it means that my last stage will be 2.5 meters wide if I have a manned mission, and it is not wise if you think of the ships delta-v.

Anyway, thank you for these tips, and any other tips are welcome also!

What does the lander can description say again?

I barely notice DRE. The first time I tried it (and FAR) I tried a few reentry tests, and aside from reentries that barely go through the atmosphere (in tests) I notice it about as much as I notice reentry in stock (not at all). I don't try to reenter landers, though (except extra-kermin missions).

[zuuhis79]

Usually I use the engine as "heatshield", as Methusalem said. I tried to solve the parachute problem by putting lights under parachutes, but they didn't protect the chutes.

To tater, lander can is not a problem, it can take 1700 degrees. Goo canisters can take 1450 degrees, they don't usually blow up. But radial parachutes take only 1150 degrees, and they are the ones that overheat and explode. But that placement tip by Methusalem to put them on battery bank is a good one, I'll try it. Hopefully it won't cause disintegration when the chutes deploy, but maybe I'll put them to deploy gradually, so they won't stress the joint so much.

I'll put this to solved state now. Thanks to all again!

[zuuhis79]

I see Methusalem posted another suggestion, it's a nice one. Can I still use the science jr experiment with a parachute on top of the hatch? I haven't tried it before...

[Methusalem]

I see Methusalem posted another suggestion, it's a nice one. Can I still use the science jr experiment with a parachute on top of the hatch? I haven't tried it before...

Should be no problem, but try it on the Landing Pad please.

And if it doesn't work, just move some stuff around: The parachutes to the sides above the Goo containers (where the solar panels are right now) and the solar panels on the front and back all the way down to the batteries. That should definitely work.

[Jouni]

The inflatable heat shield is really an easy mode for DRE on stock-sized Kerbin. It barely weights anything, and it's big enough to slow smaller ships gently down in the upper atmosphere.

[Hodo]

I would add a simple 1.25 heat shield at the bottom of the lander can and dump the finale fuel and booster stage and just return with the science and lander. This will help protect the lander can from re-entry heat and some of the other effects, and give you a fair amount of drag to slow it down before you get to low.

I also can't agree more with Taki, on the realchutes mod. I use pretty much the same settings for my pods chutes, and I also use it for drag chutes for planes on landing.

[zuuhis79]

Nice tips again. And now back to the drawing-board...