MK3 internal temperature?

[Arugela]

Why is the internal temperature so bad when it has to be in the front? There is no work around and from I can see no way to cool it sufficiently during reentry to bring it in line with other parts. I'm currently sinking Radiator Panel (Edge) on it and it has no effect. Those radiators won't cool until after you stop doing anything with the ship. They are literally designed to not work while the vessel is flying even if on and powered. Why is this done and how is it fair to purposely gimp stuff no matter what you try to do to make it stronger... Some one please explain how these are supposed to work. I put the weight and resources to use it I should get the results period end of story. This is nonsense. Radiators do not intelligently wait for engines to go off or the atmosphere to lighten to magically decide to pull heat..

I have 4 radiators sunk into it and enough power to run them and they are on. they are not denting it. And like normal not even doing any work beyond a few percentages until after in deep space if at all. I have 16 generators currently on the ship to power the 4 radiators and 5 large advanced reaction wheels. There is also an aerodynamic nose cone on the front of the MK3 cockpit.

Why are the crew cabins now designed the way they are? And why do radiators not try to pull out as much heat as possible?

Is it possible to give it enough cooling so the Internal temperature is in effect the same as the external temp? What is stupid is this is about what it takes to power a mining rig with the same parameters... Why is it not effective on crew compartments?!

 

Edited December 11, 2016 by Arugela

[Snark]

54 minutes ago, Arugela said:

I'm currently sinking Radiator Panel (Edge) on it and it has no effect. Those radiators won't cool until after you stop doing anything with the ship. They are literally designed to not work while the vessel is flying even if on and powered. Why is this done and how is it fair to purposely gimp stuff no matter what you try to do to make it stronger... Some one please explain how these are supposed to work. I put the weight and resources to use it I should get the results period end of story. This is nonsense. Radiators do not intelligently wait for engines to go off or the atmosphere to lighten to magically decide to pull heat..

No, that's not how radiators work.  Not in real life, and not in KSP.  That's not why they're in the game.

A radiator is not a magical device for eliminating heat.  It's a device for increasing heat flow.

Heat flows from hot things to cold things.  Radiators make this happen faster.  When you have a ship in the vacuum of space... vacuum's a good insulator.  So, hot ship, needs to dump heat, radiators help to transfer that heat rapidly to the frigid depths of infinite space.

Shrieking through atmosphere in a burning cloud of plasma?  Nope, not gonna happen.  The plasma around the ship is hotter than the ship.  The ship is getting hot not because it's making internal heat, but because it's being heated from the outside.  So, a radiator is not going to move heat from the (relatively) cold ship to the (hotter) surrounding plasma.  That would be making heat flow "uphill", from a colder object to a hotter one, which radiators don't do.

A radiator can only cool the ship if the radiator can "see" something colder to radiate to.  Radiator that's completely surrounded by incandescent plasma = nowhere to radiate the heat to.

What you want during reentry is the exact opposite of a radiator.  A radiator makes heat moves from hot things to cold things faster.  Since your ship is a cold thing, and it's surrounded by a hot thing... you want to make the heat transfer slower, not faster.  You want an insulator.  And that's what heat shields are for.  (Not only do they insulate, but the ones with ablator actually carry heat away by vaporizing.)  That's why nobody puts radiators on real-life spacecraft to deal with reentry heat.

In KSP, radiators were never intended as an aid for reentry; they're for dealing with other stuff, such as solar heating, or heat-generating equipment on the spacecraft.

As for "how to make spaceplane components survive reentry"-- that's a matter of spacecraft design, and piloting.  Radiators were never meant to solve your problem, and won't.  And for spaceplanes, the heat shields aren't a design option.

So, if you're having trouble reentering a spaceplane without going kaboom, the issue is going to be some combination of how your ship is designed, with how you're flying it. 

Certainly there are plenty of folks here who'd be happy to offer advice (either on design or piloting), but they'll need more information to work from.  The best thing you could do is to post a screenshot of your ship, along with some numbers (what's the mass during reentry?  how fast is it going when it hits atmosphere?  how steep a descent?)

The good news is this:  even though radiators can't help you... they don't need to.  Plenty of folks around here are flying big spaceplanes all the time, and manage to do reentry.  So it's just a matter of how you design and fly it.  Once you learn the tricks of the trade, you'll be good to go. 

 

[Arugela]

But they don't seem to pull alot of heat even when in the cold of space or at 50+k where there shouldn't be a lot of heat. They don't seem to ever work until you've been sitting in orbit for a few minutes...

And why are the internal temps so low on the crew cabins. Do they not do things to insulate them to make up for it? Are they not designed for more than that. Why is it ok for a cargo bay and not a crew cabin. If the excuse is the windows can you not make a way to close/block them?(I'm assuming that isn't the reason though) Are there not material that can or should be in it to give it more leway than this? You are going to store things in a cargo bay just as sensitive as a crew compartment or more potentially. I don't get where it is coming from.

Edited December 11, 2016 by Arugela

[Starwaster]

Snark is right; you need to shift focus away from radiators and onto how you're reentering. Because spaceplane parts don't have ablative shielding they need a different reentry profile. Specifically shallowly instead of steeply. You want to do as much aerobraking in the upper regions of the atmosphere where the air is thin.

[Arugela]

Yea but what is the reason for the low internal temperature unique to the crew cabins? Why is it low and not the cargo bays etc? What is the reasoning? I imagine it's something besides balance.

Edited December 11, 2016 by Arugela

[Snark]

1 minute ago, Arugela said:

But they don't seem to pull alot of heat even when in the cold of space or at 50+k where there shouldn't be a lot of heat. They don't seem to ever work until you've been sitting in orbit for a few moments...

Careful, you're mixing apples and oranges.  There's a LOT of difference between the vacuum of space and plowing through atmosphere at 50 km.  There's lots of heat at 50 km.  Try taking an orbiting spaceship, and lower its Pe to 50 km, then turn on the thermal overlay with F11 and watch what happens when you dip into the atmosphere.  Things start to get hot in a hurry.

Even very thin gas will heat up your ship pretty quick when it's slamming into you at more than two kilometers per second.  Putting radiators on a ship in that situation will just be giving more surface area for the hypersonic atmosphere to slam into.  Not a winning strategy.

In the vacuum of space:  then radiators will help.  And yes, it's a bit slow.  That's how radiators work.  They can't radiate heat effectively until they get hot, and it takes them a while to warm up.

5 minutes ago, Arugela said:

And why are the internal temps so low on the crew cabins. Do they not do things to insulate them to make up for it? Are they not designed for more than that. Why is it ok for a cargo bay and not a crew cabin. If the excuse is the windows can you not make a way to close them? Are there not material that can or should be in it to give it more leway than this?

Well, there you'd have to go and ask Squad why they decided to design the parts the way they did, for game-balance reasons.

But, as I said, the good news is that a spaceplane can reenter just fine as it is.  If you're having problems, it's because there's some issue either with how you're designing your ship, or how you're flying it, or both.  If you want to solve the problem, you need to figure out what you're doing wrong, and address that.

So, the best way for you to do that is, post a screenshot of your ship, along with some basic numbers as I described above.  Then I'm sure there are plenty of people who can offer helpful advice.

[foamyesque]

@Snark: Strictly speaking a real life radiator can, in fact, radiate from a colder environment to a hotter one. Very high altitude atmospheric temperatures are several hundred degrees C, but the air's so attenuated the convection flux is functionally nil, and so whether or not a radiator can act to cool a craft is a question of net radiant flux. If they're edge on to the Sun, there's nearly no incoming thermal energy from solar radiation, and so you can cool a craft despite it being immersed in a medium which has, theoretically, a temperature noticeably higher than the stuff you're trying to cool.

On the other hand, try to operate a radiator in boiling water and you're in for a bad, bad time. :v

[Arugela]

That could make stuff fun in the game if they every added underwater exploration and details to water and craft... sounds interesting actually.

I wish they would add more details to why the parts work why they do(in the parts just not given values). Then you could go in depth and find solutions. Not just be at the mercy of them. It would also be easier to learn the game. Having flat simpler numbers and formulas is not really conducive to learning from experience in an environment. Simplicity makes it harder. Less to look at.

I'd rather not have to look up everyone on a separate or partially separate site(assuming I can find the info even then.). Let alone a few formulas dictating everything. It's, again, to simple. Having more characteristics and details make it easier to observe and go over to learn.

I hope they go into the material and engineering side eventualy. At least hash out what is there and let people modify it.

Edited December 11, 2016 by Arugela

[Snark]

11 minutes ago, Arugela said:

Yea but what is the reason for the low internal temperature unique to the crew cabins? Why is it low and not the cargo bays etc? What is the reasoning?

You'd have to ask Squad.  If I had to guess, I'd say it's because of game balance reasons, to account for the fact that they have people (well, okay, kerbals) in them, and therefore are presumed to be more delicate.  But that's just a guess, obviously I don't speak for Squad since I don't work there and wasn't privy to any of their design decisions.

10 minutes ago, foamyesque said:

Strictly speaking a real life radiator can, in fact, radiate from a colder environment to a hotter one. Very high altitude atmospheric temperatures are several hundred degrees C, but the air's so attenuated the convection flux is functionally nil

Sure, and that's fine if the thing you're cooling is something like a weather balloon, that's just sitting at zero relative velocity to the atmosphere.  But when you're surrounded by gas that's slamming into you at orbital velocity, you're going to be getting hot unless it's incredibly thin, to the point of virtual nonexistence.

Certainly in KSP, it's modeled in a way that you heat up rapidly in the upper reaches of atmosphere when traveling at orbital speed.

And in any case... there's no way a radiator would help with the heat of reentry.  The incoming heat flux from reentry is going to far outweigh anything that the radiators could hope to do.

10 minutes ago, foamyesque said:

On the other hand, try to operate a radiator in boiling water and you're in for a bad, bad time.

And trying to operate it in the midst of an incandescent reentry-plasma shockwave at several thousand degrees would be even worse than boiling water.

Be that as it may: this is all a moot point, since that's a real-world science discussion, whereas the OP here is having problems with spaceplanes in KSP.  So if you'd like to have a discussion about how radiators work in the real world, that would be good to take over to the Science & Spaceflight forum. 

 

[Jestersage]

Spaceplane is best when entering from a 70k x 70k orbit, make PE at 20K with the belly. Also one of the reason I dislike the standard SSTO answer, because the flight time greatly increases.

If you want to enter direct (thus, the part WILL get hot), you have to stick with capsule. There is a reason why NASA picked a capsules design instead of Lockheed's Winged CEV. IRL, Space shuttle can only fly in LKO, and even with its heatshield require S-turns and pitch up to 40 degrees to enter.

Edited December 11, 2016 by Jestersage
Corrected for Mk3 cabin.

[foamyesque]

1 minute ago, Snark said:

You'd have to ask Squad.  If I had to guess, I'd say it's because of game balance reasons, to account for the fact that they have people (well, okay, kerbals) in them, and therefore are presumed to be more delicate.  But that's just a guess, obviously I don't speak for Squad since I don't work there and wasn't privy to any of their design decisions.

Sure, and that's fine if the thing you're cooling is something like a weather balloon, that's just sitting at zero relative velocity to the atmosphere.  But when you're surrounded by gas that's slamming into you at orbital velocity, you're going to be getting hot unless it's incredibly thin, to the point of virtual nonexistence.

Certainly in KSP, it's modeled in a way that you heat up rapidly in the upper reaches of atmosphere when traveling at orbital speed.

And in any case... there's no way a radiator would help with the heat of reentry.  The incoming heat flux from reentry is going to far outweigh anything that the radiators could hope to do.

But in any case, this is all a moot point, since that's a real-world science discussion, whereas the OP here is having problems with spaceplanes in KSP.  So if you'd like to have a discussion about how radiators work in the real world, that would be good to take over to the Science & Spaceflight forum. 

 

 

The thing is, radiators in KSP don't match radiators in the real world (or even sane sim thereof). I've got a thread running over in tech support about it.

And certainly it's true that radiators won't help with peak reentry heats at all. They should, however, be able to cool parts once you're up past 60km or so (depending on your speed, but in general), when convective flux drops to pretty much nil and you can easily have skin temperatures well under your internal temperatures. In KSP, however, they don't.

[Snark]

4 minutes ago, foamyesque said:

They should, however, be able to cool parts once you're up past 60km or so (depending on your speed, but in general), when convective flux drops to pretty much nil and you can easily have skin temperatures well under your internal temperatures. In KSP, however, they don't.

Sure... but, as we agree, not with reentry heat.  Which is what the OP's asking about, here.  You can't radiate your way out of reentry burn-up... not in KSP, and not in real life, either.

You can insulate, and/or you can ablate.  That's basically it.

[Arugela]

I'm readjusting the cockpit area to have an upper MK2 area with two cockpits and a lower one with things that can take heat. I'm using the MK3-MK2 adapter in the same spot with one facing upwards and one with the node downwards. I hope that gets rid of the heat issue. The lower area should be blocking the heat for the upper area. I'll get a pic in a second.

Pic:

 

The cockpit used to be an MK3 cockpit where the two adapters are.

Would the non cockpit parts I stick in the bottom unused node be able to block heat for the upper area with cockpits? Or does the game not do that atm?

Pic: (With lower portion filled)

This plane will be too big for the hanger if I add much more.

Edited December 11, 2016 by Arugela

[foamyesque]

11 minutes ago, Snark said:

Sure... but, as we agree, not with reentry heat.  Which is what the OP's asking about, here.  You can't radiate your way out of reentry burn-up... not in KSP, and not in real life, either.

You can insulate, and/or you can ablate.  That's basically it.

Y'might actually be able to if radiators worked. Sure, not at peak, but KSP radiator temps are 1700K or so; on a LKO reentry it's a fairly brief period where you see skin temps higher than that, and the internal temps allowed for some of the cockpits and passenger modules are only 1000K-1100K. A radiator could potentially keep those part's internal temperatures from absorbing further skin flux and hitting their critical temps. Except the heat pump doesn't engage even in circumstances where it should; you can get bigger cooling effects by opening a cargo bay!

[Snark]

36 minutes ago, Arugela said:

That could make stuff fun in the game if they every added underwater exploration and details to water and craft... sounds interesting actually.

I wish they would add more details to why the parts work why they do(in the parts just not given values). Then you could go in depth and find solutions. Not just be at the mercy of them. It would also be easier to learn the game. Having flat simpler numbers and formulas is not really conducive to learning from experience in an environment. Simplicity makes it harder. Less to look at.

I'd rather not have to look up everyone on a separate or partially separate site(assuming I can find the info even then.). Let alone a few formulas dictating everything. It's, again, to simple. Having more characteristics and details make it easier to observe and go over to learn.

I hope they go into the material and engineering side eventualy.

Well, that's a whole other discussion-- that's all about "here's what I think Squad should do" as opposed to "why doesn't my spaceplane work".

This forum right here (Gameplay Questions) is for the "why doesn't my spaceplane work" type of question, looking for "here's how to fix it" type of answers.

If you'd rather talk about "here's what I want Squad to do," that's great!  But not right here-- there's a Suggestions forum for that. 

36 minutes ago, Arugela said:

let people modify it.

But they do!  That's what mods are.

If you want the parts to have different numbers (e.g. a higher temperature tolerance, or whatever), you don't even need to write code-- just a few lines of ModuleManager config will tweak whatever you want to any number you want.

If you want the fundamental programming model of the game to change... that can be modified, too, though it requires writing code.

But it's definitely modifiable!

19 minutes ago, Arugela said:

I'm readjusting the cockpit area to have an upper MK2 area with two cockpits and a lower one with things that can take heat. I'm using the MK3-MK2 adapter in the same spot with one facing upwards and one with the node downwards. I hope that gets rid of the heat issue. The lower area should be blocking the heat for the upper area. I'll get a pic in a second.

Pic:

Thanks, the screenshot answers a lot!  There's a big part of your problem right there.  You've got a huge, massive ship built like a javelin.  Really high ballistic coefficient, which is bad for reentry (you want it to be low, not high).  And nearly all of your mass is the low-temperature-tolerance parts.  Recipe for disaster.  You've designed a ship that will get heavily punished, and you've designed it to focus that punishment precisely on the parts that are worst-equipped to handle it.

Make it a lot smaller, and put a lot more wings on it.  The spaceplane wings have a high temperature tolerance, and presenting them face-on to atmosphere will generate a huge amount of drag.

Shrink it to half the mass (thus half the punishment), triple the mount of wing (thus more of the punishment goes to wings instead of passenger compartments), and I'll bet you do a lot better.

Also, what's your reentry scenario?  Are you coming back from the Mun (or interplanetary)?  Or is this just reentering from LKO?  What's your attitude while reentering?

[Arugela]

I got a bunch of stuff on the aircraft done now. It's working really well as far as kerbin goes. I released it in the exchange forum if you want to see it. I think I resolved the heat issues for the most part.

 

[KevinW42]

Another solution is to enter with an angle of attack as close to 90° as you can manage. With all the drag that gives you you'll decelerate much faster and spend less time screaming through the atmosphere in a ball of superheated plasma.