Eve lander disintigrating

[martinborgen]

Hello all. I've found that my Eve lander consistently disintigrates because of heat issues. Struts and full fuel tanks overheat - despite having heat shield on the bottom (forward facing) end of the lander's stacks. I've aerobraked several passes, but even getting my orbit down to 1500km ap (which took a month, because of shallow pe, also because of heat issues), I feel that there's no way I can get the thing down. I see lots of very large and rapid fluctuations on the heat bars, so I suspect the engine can't handle the heat transfers quick enough. Even so, after turning ignore max temp on, I found that several parts, even un-heatshieldable parts like struts, goes to red (ie. exploded due to heat if not for cheat) heat all through the descent. Despite all this, the heat shields have plenty of ablator left? So apart from burning a crapton of fuel all the way down, how do you do it?

[Warzouz]

Wrong forum.

You don't need heat shields to land on Eve, you need Airbrakes. You must lower your speed for reentry.

I've landed a 180Tons with airbrakes and chutes. Drogues aren't usefull. Airbrakes will slow you down to 200m/s when you can open chutes (not 250 as on kerbin !)

It you go too hot, add more airbrakes.

[Red Iron Crown]

Moved to Gameplay Questions.

[martinborgen]

Thanks, wrong forum, my mistake.

So do you use fuel to get down below orbital velocity while still in space? Or do you have a low eve orbit and just use air brakes from upper eve atmosphere in a standard descent?

[tseitsei]

You need more drag. Airbrakes, wings, control surfaces and trying to keep a bigger AoA while in the upper atmosphere to bleed off enough speed while still in the thinner atmosphere

[Warzouz]

Thanks, wrong forum, my mistake.

So do you use fuel to get down below orbital velocity while still in space? Or do you have a low eve orbit and just use air brakes from upper eve atmosphere in a standard descent?

No don't waste too much fuel, you'll need it to take of

You have to find a shallow angle and airbrakes combination. Use KER to show "critical temp". Mine is usually between 90 and 95%. I even landed a ship after it was up to 98.5% of max temp.

Edited September 22, 2015 by Warzouz

[martinborgen]

OK. I can however proudly announce that allthough the lander couldn't survive re-entry, it was capable with margin to take of from 1000m above sea level - even though the second stage flipped and I oversped the rocket. Then again, the thing weighs 280 tons fueled up, so it better be.

Now then, back to the drawing board, and get the design with A.I.R.B.R.A.K.E.S. and wings etc.

Edited September 22, 2015 by martinborgen

[Warzouz]

It's possible to land on Eve

Without airbrakes

Without chutes

Without drogues

Without heat shield

only Ker-balls !

http://forum.kerbalspaceprogram.com/threads/130104

[martinborgen]

Haha, well I've landed small things, no problems.

[juanml82]

I'm trying a large Eve lander as well. My approach is to use the larger delta wings (the ones you can put fuel to) connected to an infernal robotics hinge to rotate them and put them parallel to the ground. That way, they work as very large aerobrakes.

See here

In order to keep them steady while taking off from Kerbin, I've struted them to radial decouplers (so I can easily remove the struts before entering Eve)

Now, this approach is rather complicated. Spamming aerobrakes, if it works for your design, is simpler.

Also, use spaceplane fuel tanks and avoid any part with less than 2000 degrees of heat tolerance. Whenever possible, aim for higher tolerances, as 2000 might not be enough.

[xebx]

Ablator of heatshields reduce heat and Airbrakes also acts as radiators, both help a lot when you need to land something big.

Drogues are useless, low atmo is very dense, but chutes saves fuel.

I've often aimed for 55-70km (from 100-300km half orbit) for a good atmo entry.

All gigantor panels survived, the problem was the airbrakes or some struts near the heatshield assembly.

[martinborgen]

Yes, I am redesigning the lander with new experience. Now, I won't fuel it from Gilly as first done, but on Eve, hence the desing will be a lot lighter. Lots or aerobrakes and four big S delta wings will hopefully alow me to steer the craft, as well as better heat shield arrangement. I did not know airbrakes acted as radiators? That seems a bit odd, but I guess they would explode otherwise.

[xebx]

Well, not sure about the radiator term/feature for airbrakes, let's say they increase your surface/drag, they heat due to friction, they slow your ship and transfer partially the heat to the air and the rest of the ship, otherwise they would explode yep (they are near critical temp during first descent part). The higher part of the atmosphere (>50km) is the main problem, although i had one or two disintegration at 30km during tests.

Yes refuelling on Eve is a good idea, it makes your ship lighter.

I made one or two tests yesterday with a fully fuelled ship, and all boom. But it didn't have enough control/reaction wheels and i didn't use engines/extrafuel to slow. (this is the plan)

Edit : airbrakes acts as radiators, because they overheat, they glow, they radiate (infrareds etc). It's nearly obvious, don't know what i was thinking about.

Edited October 2, 2015 by xebx