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What do you do, if you're too fast?

Krugz

By Krugz
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Krugz

Krugz

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So, I have a craft that goes around 2.2km/s by the time it\'s at 30km, and the command pod is exploding due to overheating:

'[00:00:53]: Command Pod Mk1 exploded due to overheating.' :\'(

*Edit:* This is on launching my ship, not on re-entering the atmosphere.

Is there any way around this (aside from slowing it down)?

Sorry if this is already on the forum somewhere, I did a search but didn\'t come up with anything relevant to command pods overheating...

TIA!

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Krugz

Krugz

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;D thanks, I think I solved the problem, sort of... I added a second decoupler before the command pod, somehow this has solved the problem? I can\'t quite get to 2.2k now though, getting to 2.0k instead. If you have any better ideas, I\'m still working on this.. I might revert to the one that was exploding at 2.2k and save it just as a souvenir.

Edit: Ok so, I deleted the since-added parts, and it\'s not overheating at 2.2km/s @ 30~34km height anymore... maybe it was just a bug? It\'s hard to reproduce the flight because the early stages slowwwww down my computer and even though I spam the spacebar, the stages don\'t separate fast enough to not lose some of my speed.

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Krugz

Krugz

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Something tells me it isn\'t stock parts... I don\'t think it is a 'problem' as much as overkill... you would never need to get to 2.2km/s at 30km alt... why would you need that much power?

I\'m not using any modded parts, I swear. As for overkill, ya it is! I\'m trying to get a base platform for getting into space as fast as possible, then I\'ll add a ton of longer-duration stuff on top, so I can have optimal fuel/control in space as well. It\'s just kind of my way of having fun, anyways =P .

...Throttle down...? :o

Can\'t, it\'s all boosters right now :-[

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Tiberion

Tiberion

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Err, we don\'t currently have heat damage due to friction in the atmosphere, all heating is caused by engine output; so if your pod was overheating its because it had too many boosters closely attached to it, and was unable to dissipate their heat.

It sounds like you are overbuilding; you might be interested in the G-force meter on the right side of the nav-ball; if you\'re ship is accelerating that much you\'re likely killing your kerbals (or you will be one day, its another thing not modeled yet)

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Krugz

Krugz

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Err, we don\'t currently have heat damage due to friction in the atmosphere, all heating is caused by engine output; so if your pod was overheating its because it had too many boosters closely attached to it, and was unable to dissipate their heat.

It sounds like you are overbuilding; you might be interested in the G-force meter on the right side of the nav-ball; if you\'re ship is accelerating that much you\'re likely killing your kerbals (or you will be one day, its another thing not modeled yet)

Hmm, that\'s weird, then.. I don\'t know how that was happening, there were other parts breaking but they weren\'t colliding with the command pod yet, nor was it directly next to/in the exhaust of any engines.

I should have taken screenshots before I changed things, now I can\'t get it to explode anymore even when I get back to the same speed/distance. I think when I was originally doing it, I was at a much straighter angle directly up. Like I said, I\'ve been having a hard time forcing it to replicate what I was doing before. I\'ll finish up my ship and then come back to the exploding version and see if I can duplicate it + screenshot/stream it.

@killing kerbals: Oh, that might be a problem, but I\'m still determined to make something insanely fast ;D . You have to break a few kerbals to make an omelet, or a silly spaceship.

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Krugz

Krugz

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I am curious to know how you managed to get to 2.2km/s at 30k altitude... mind posting your craft file?

Sure, I don\'t mind. The idea I had (in a stage of development way later than the attachment) didn\'t really pan out, I didn\'t factor in the fact that my computer is a few years old now, despite being a monster PC when I first got it. I lag too much to properly separate the stages of my current product.

Anyhow, the craft file should be attached to this post, if I did it right. Make sure you turn on SAS before you launch..

The crash report, ~2.3km/s @ ~31k : (strangely only had 2.0 Gee Force, but I\'ve definitely had it report like 26.4 once... maybe that was a bug?)

overheatingcommandpod1.jpg

overheatingcommandpod2.jpg

Be kind to Kerbals!

I kindly assist in getting them to kerbhalla, where the kermanliest kermen go.

If you\'re on liquid engines, throttle down.

If you\'re on SRBs, god help us all.

Jeb help us all you mean

Better start praying, then.

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Richy teh space man

Richy teh space man

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I see what the problem is..

Solid rocket boosters are ok for giving you that little extra oomph on takeoff, but I don\'t recommend grouping loads of them together as they have a tendency to explode lolz

I\'d suggest liquid fuel engines as your main drive.. that\'ll also make it easier to get into a circular orbit around Kerbin, if that is what your trying to do

But I\'d recommend ditching those srbs for now

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UmbralRaptor

UmbralRaptor

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Drag race much?

I\'m going to guess that joints got overstressed (these sorts of ships get rather bouncy towards the end of the first stage burn), there was a collision, and then everything exploded. Depending on how close to the edge, a given design is, slight changes may make it dramatically more or less stable.

And yeah, if the goal is something a bit less silly, you want liquid engines.

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Bluejayek

Bluejayek

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Since when will the capsule burn up? A couple weeks ago (in 0.14) I hit atmosphere going over 6000 and had a g-force that should have been 100+ (didn\'t read correctly). I did not burn up. I don\'t see how you would burn up coming out at 2000 if I didn\'t burn up going in at 6000...

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Krugz

Krugz

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I see what the problem is..

Solid rocket boosters are ok for giving you that little extra oomph on takeoff, but I don\'t recommend grouping loads of them together as they have a tendency to explode lolz

I\'d suggest liquid fuel engines as your main drive.. that\'ll also make it easier to get into a circular orbit around Kerbin, if that is what your trying to do

But I\'d recommend ditching those srbs for now

Drag race much?

I\'m going to guess that joints got overstressed (these sorts of ships get rather bouncy towards the end of the first stage burn), there was a collision, and then everything exploded. Depending on how close to the edge, a given design is, slight changes may make it dramatically more or less stable.

And yeah, if the goal is something a bit less silly, you want liquid engines.

My idea is to have a massive stage early on that can support the weight of a large/medium sized ship with liquid engines. I guess my thought process is 'the more liquid fuel I get into space without spending any, the easier it is to go wherever I want later.' So this was one approach on how to achieve that, I basically figured if I can super fast with a large ship, it can probably support a lot of weight and get out into space slowly? Something like that...

Since when will the capsule burn up? A couple weeks ago (in 0.14) I hit atmosphere going over 6000 and had a g-force that should have been 100+ (didn\'t read correctly). I did not burn up. I don\'t see how you would burn up coming out at 2000 if I didn\'t burn up going in at 6000...

According to Tiberion, it\'s probably just my engines overheating/colliding. The weird thing is, by the look of things, they never collide with the command pod.. but if you look at the report images, they may have been colliding into the decoupler which then exploded and overheated the command pod? I\'m not sure.

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UmbralRaptor

UmbralRaptor

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My idea is to have a massive stage early on that can support the weight of a large/medium sized ship with liquid engines. I guess my thought process is 'the more liquid fuel I get into space without spending any, the easier it is to go wherever I want later.' So this was one approach on how to achieve that, I basically figured if I can super fast with a large ship, it can probably support a lot of weight and get out into space slowly? Something like that...

If we\'re talking stock parts, liquid fuel offers an Isp just over 2.5x that of solid fuel. For launching large(ish) payloads, I\'m partial to using stacks of 4 tanks above an LV-T30. This arrangement can get a bit over 3 tonnes to a 70 km orbit, and can be radially stacked. The centerline engine often gets replaced with an LV-T45 for additional control. I\'m unsure if 4 tanks is optimal, though. (I suspect that 3 is for suborbital launches, and 5 for emphasizing ?V over payload)

STSTE0.png
According to Tiberion, it\'s probably just my engines overheating/colliding. The weird thing is, by the look of things, they never collide with the command pod.. but if you look at the report images, they may have been colliding into the decoupler which then exploded and overheated the command pod? I\'m not sure.
Once an explosion starts, it tends to spread, destroying the entire rocket. I think we need to develop a CASE for fuel? >_>
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Zephram Kerman

Zephram Kerman

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If we\'re talking stock parts, liquid fuel offers an Isp just over 2.5x that of solid fuel. For launching large(ish) payloads, I\'m partial to using stacks of 4 tanks above an LV-T30. This arrangement can get a bit over 3 tonnes to a 70 km orbit, and can be radially stacked. The centerline engine often gets replaced with an LV-T45 for additional control. I\'m unsure if 4 tanks is optimal, though. (I suspect that 3 is for suborbital launches, and 5 for emphasizing ?V over payload)

An easy way to check if your rocket is under- or over-powered is MechJeb\'s autothrottle. If it\'s at 100% all the time, you should add engines somewhere or remove mass. If it\'s throttling back too much, you can remove engines to save mass without any performance penalty (in atmosphere). I like to use stacks with one engine for every three fuel tanks. Depending on the payload mass, I\'ll surround it with more of those stacks.

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Krugz

Krugz

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An easy way to check if your rocket is under- or over-powered is MechJeb\'s autothrottle. If it\'s at 100% all the time, you should add engines somewhere or remove mass. If it\'s throttling back too much, you can remove engines to save mass without any performance penalty (in atmosphere). I like to use stacks with one engine for every three fuel tanks. Depending on the payload mass, I\'ll surround it with more of those stacks.

Personally I\'m not a big fan of using tools made by other people, I\'ll probably do some spreadsheets/calculations to decide the optimal configuration ???

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