Any luck lifting from Eve since 1.0.5?

[Foxster]

I can't seem to make orbit now from Eve without my craft exploding due to overheating.

Its the last stage (nosecone, Mk1 capsule, FL-T400 tank, Terrier) that heatplodes. Once the speed starts to come up a bit then the heat runs away. This stage only has TWR of 0.9, so it's hard to see how to slow it down and still make orbit. This craft used to make orbit no problems.

I've tried adding radiators and that did nothing. I have tried lots of flight profiles, including not turning until 30km to get out the souposphere. No luck.

Anyone tried it yet?

[fourfa]

My big ascent vehicle didn't need any changes to make orbit from sea level.

I have noticed that flight profile matters - the new build of mechjeb for 1.0.5 includes a new-to-me option for MaxQ limiting - when I tried turning that on, the leading Mk1 capsule blew up. Turned off, back to no problems. I guess the amount of time spent throttled-down for limited Q leads to more turn at lower altitude, and more acceleration in atmosphere instead of circularization.

So, maybe try a slightly more vertical ascent? I'm programming mechjeb to start turning at 20km at no more than 6 degrees AoA, no maxQ, 66.6% shape.

[Foxster]

Thanks for that. I've tried a similar ascent shape but without limiting the AoA as you did. Of course, without MJ this would be very difficult.

- - - Updated - - -

Tried it. Still blowing up.

Could you post a picture of the craft you are using please?

[Gaarst]

As the Vector has the same Isp specs as the Mammoth (and insane thrust), I see Eve ascents becoming a lot easier with smaller crafts in 1.0.5.

That is after solving the overheating problem, of course.

[Foxster]

As the Vector has the same Isp specs as the Mammoth (and insane thrust), I see Eve ascents becoming a lot easier with smaller crafts in 1.0.5.

That is, after solving the overheating problem, of course.

Yes, that's the theory I have been trying to test. But all the craft with or without a Vector engine blow up

Here's one of my old craft that I have been using because it's simple and has just 2 stages. Used to be able to make orbit no problems: https://www.dropbox.com/s/d3vwgr44c0aw676/Eve%20again%201.craft?dl=0

If someone would like to try it just to make sure it's not something gone screwy with my install?

Edited November 11, 2015 by Foxster

[Foxster]

This makes orbit no problems (with heat turned off in debug)...

[Foxster]

As does this...

[juanml82]

Well, my first idea would be to use the MK2 parts, as they resist heat better, but I've yet to try it.

I'm still trying to relearn how to reenter from LKO

[fourfa]

Could you post a picture of the craft you are using please?

Sure:

http://imgur.com/a/q1CbS

This is a bit particular to my own mission profile: two copies of all science from every biome, necessitating two separate cabins. After testing a LOT of combinations in 1.0.4 this is what I ended up with. A brute force solution, to be sure, but very reliable. KER says 8311m/s. There are surely other/cheaper/smaller ways to do it, but I wanted sea level capability and to look like a actual rocket. Without the side boosters, it works well from maybe 3000m and up if you can keep it from tipping on landing. The design and testing was a lot of work but fun as hell!

Since 1.0.5 I was able to clean up the shenanigans needed to stack attach Aerospikes, but I haven't been able to get that bottom interstage fairing to close again. What a pain in the rear. My testing showed the interstage fairing saved a couple hundred m/s of dV over none at all. I use GPOSpeedFuelPump for convenience, but otherwise it runs 100% stock. You just need to keep the topmost S3 tank full with manual transfers.

Edited November 13, 2015 by fourfa

[Foxster]

Umm, I wonder what's different about that so you don't get the thermal ruanaway I do at 30-40km? It might be the much more massive top section dissipating heat?

I really don't want to have to build 3 x Mammoth craft for Eve though just to put one man in orbit.

[fourfa]

Yeah, neither did I but before the Vector, everything I tried was just marginal and not very repeatable. I found the avionics nose cose has higher drag than the small nose cone (more heat maybe, if you're using that?)

I'd definitely try swapping the Terrier for an Aerospike, might give you more flexibility with your power profile. Maybe the low TWR is letting the atmosphere slow you enough that you're staying in the upper sections longer than you should.

The tapered adaptor fuel tank might be cool for your final stage, but you'll definitely need an interstage fairing if you do. And if your lower stages don't throw you high enough, the rear drag is pretty high. I experimented with the Rockomax Adaptor 02, which definitely reduced drag when exposed, but once I started using the 2 Mammoth boosters, that happened so high that it wasn't worth the weight penalty. That might be the start of the complexity and weight scaling up towards 3X Mammoth....

Edited November 13, 2015 by fourfa

[technion]

As does this...

Did something drastically change in 1.0.5? Because I had a near identical inner section on a rocket, and another stage of aerospikes outside that, and it really struggled.

I seemed to be more effective at dealing with Eve in pre-1.0 when I had these massive contraptions.

[Foxster]

Did something drastically change in 1.0.5?

The things that changed that seem relevant so far are: aerospikes lost 1/3 their mass, we gained the Ventor engine BUT they messed with the atmosphere. The idea with the atmosphere was to allow aerobraking again without the instant heatplosion of 1.0.4. Unfortunately that seems to have introduced a dense layer at 30-40km or so where the drag and temperature goes through the roof. Meaning I simply haven't succeeded in getting anything to orbit yet.

[Signo]

I think the resistance of the whole craft now depends a lot on the first piece in contact with the aerodynamic flux - as far as I know the best "spearhead" I found is the shielded docking port: I made some experiments with a few planes on kerbin and I tried a full Eve mission (blown up in Eve's upper atmo trying to aerocapture).

Look at this short video - with a shielded docking port you can almost divebomb your descent from LKO -

http://www.twitch.tv/signo1974/v/25578210

[Tatonf]

That would require a bigger craft (because more delta-V) but using a less efficient ascent profile where you don't exceed a certain speed might be the solution.

[Foxster]

I'm really sucking with 1.0.5.

We are supposed to be able to aerobrake over Eve now. Well, it takes a better man than me.

I made my smallest new lander/lifter for Eve and hid it behind the biggest heat shield. I went around Eve 5 times, barely slowing each time and then the heat shield ablative was gone and the next time it was kabloowie!

Ah, how I miss the old days of diving into Eve's atmosphere, slowing down and landing. The fun has really been sucked out of the game by some random desire for "reality", which is obviously nonsense in this game.

[Foxster]

This is starting to get close to being more heat tolerant...

Trouble is that two things are still stopping it working:

1. The drag of the radiator panels tends to make the craft flip. They have to be on the top there as that's the hottest part. Dunno what to do about that.

2. The extra drag of the radiator panels combined with the extra drag of the atmosphere at higher altitudes introduced with 1.0.5 means the craft runs out of steam and can't make orbit.

[The Flame Cat]

This is starting to get close to being more heat tolerant...

http://i.imgur.com/8FcmnkN.jpg

Trouble is that two things are still stopping it working:

1. The drag of the radiator panels tends to make the craft flip. They have to be on the top there as that's the hottest part. Dunno what to do about that.

2. The extra drag of the radiator panels combined with the extra drag of the atmosphere at higher altitudes introduced with 1.0.5 means the craft runs out of steam and can't make orbit.

I think that you should maybe

put the radiator panels on the side of the craft.. That could possibly work.

[sdj64]

This is starting to get close to being more heat tolerant...

http://i.imgur.com/8FcmnkN.jpg

Trouble is that two things are still stopping it working:

1. The drag of the radiator panels tends to make the craft flip. They have to be on the top there as that's the hottest part. Dunno what to do about that.

2. The extra drag of the radiator panels combined with the extra drag of the atmosphere at higher altitudes introduced with 1.0.5 means the craft runs out of steam and can't make orbit.

In 1.0.5 they changed radiators, they now take heat from the whole craft so you can place them anywhere you want. I don't have hard proof of this but here's a comparison:

1.0.4 only the lower radiators show any signs of heating.

1.0.5 notice the front radiators glowing too. Nukes seem to produce more heat as well.

I tested an updated version of my grand tour Eve lander in 1.0.5, with the nose cones switched to shock cone intakes and airbrakes switched for more wings for higher heat tolerance. It uses a seat in a service bay, though. The Mk1 capsule has a bit lower heat tolerance than a shock cone but it should work, the key is to punch it through the lower atmosphere but once the flames start appearing, back off on the throttle. Wings also have tons of drag at high angle of attack and seem to not be overheated easily by Eve's atmosphere so you can use them on the way down.

This is the lander I used:

[Foxster]

Umm, I have a feeling that the extendable radiators take the heat from the whole ship but that the fixed panels cool only the part they are attached to and just possibly the adjacent one. I can't use the extendable ones, they break as soon as underway.

Have you actually tried your craft from Eve? Did it make it to orbit?

[sal_vager]

Yep, the fixed radiators will cool the part they are attached to and every part attached to that, including its parent.

Also, and no one seems to have noticed yet, but struts will conduct heat now...

[Laie]

Aerospike *data* hasn't changed since 1.0.3, only the model.

A quick test suggests that Eve's atmosphere is still very thick even at high altitudes.

a) Hyperedit to 100km Eve orbit, then -20m/s for a 80km periapsis. Atmo starts at 90km.

at 85km I can turn off the reaction wheels, ruddders suffice.

c) by 80km, my wings create enough lift for me to climb again.

I'd recommend to clear the atmosphere before you accelerate to orbital speeds. That is, either the "up and take a left" approach or aiming for a higher orbit right away. Launching to 150km isn't much more expensive, but dramatically cuts down on the time spent in atmosphere.

[technion]

A quick test suggests that Eve's atmosphere is still very thick even at high altitudes.

This could play into a terrier top stage being less effective.

[Foxster]

Well, I finally made it, with 600dV to spare in the end, so I could even cut the craft down a bit...

The "secret" for anyone trying at Eve is to cut the drag on the last stage to the absolute minimum. It's much more draggy in Eve's upper atmosphere than in 1.0.4. If you hit that patch of draggy atmosphere at high speed with some drag on your craft then it will heatplode.

I used my old "trick" of rotating the nosecones and that dropped the peak part temp in the upper atmosphere from about 4000° to 500°! Would rather not have used this method but I figure Squad messed up the atmosphere by mistake so I'll not feel too bad about it.

The best MJ ascent path I found for this craft was...

Edited November 14, 2015 by Foxster

[Tatonf]

But just as I told you in the Eve challenge topic, the canards are heatploding during reentry from LEO.

But well I gues it's small enough so we can put it into a fairing with a heatshield, so nice job !