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Fix for shock heating on assent yet?


Superluminaut

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Going slower?

It's not a bug: your rocket goes fast in atmo, you have shock heating, direction doesn't matter.

If this really bothers you, either go for steeper ascent profiles (gaining speed higher up) or deactivate aero effects during your launches.

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24 minutes ago, Gaarst said:

Going slower?

It's not a bug: your rocket goes fast in atmo, you have shock heating, direction doesn't matter.

If this really bothers you, either go for steeper ascent profiles (gaining speed higher up) or deactivate aero effects during your launches.

It's a "bug" due to kerbal scale.

I still like mach effects though. But how do you deactivate, can you hot key it? Can you cut them off at x velocity?

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1 hour ago, Superluminaut said:

Could you share how exactly you do it?

Don't punch it/put the rocket on full throttle/throttledown when the effects appear/go higher first? These are all piloting/craft things. You can turn off atmospheric effects in the settings, but it will still blow up. You've only disabled the graphics.

Edited by qzgy
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55 minutes ago, qzgy said:

Don't punch it/put the rocket on full throttle/throttledown when the effects appear/go higher first? These are all piloting/craft things. You can turn off atmospheric effects in the settings, but it will still blow up. You've only disabled the graphics.

These changes would all result in rocket performance losses. Nothing blows up. Like said before it's a game issue, I'm just looking for a work around that doesn't take away from the game.

Edited by Superluminaut
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1 minute ago, Superluminaut said:

These changes would all result in rocket performance losses.

Then change the rocket to account for the performance loss. A performance loss is better than an overheated one.

If anything, it might actually help your rocket, as then you're not losing delta v to drag losses.

Edited by qzgy
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1 minute ago, qzgy said:

Then change the rocket to account for the performance loss. A performance loss is better than an overheated one.

If anything, it might actually help your rocket, as then you're not losing delta v to drag losses.

Look at the video, no drag losses, not even close. G losses  however will increase with your suggestions.

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Well, since everybody else can fly their rockets without this issue creeping up, or if it does, they all realize it's a piloting issue, then it must be the games fault for having a bug that doesn't recognize your perfect skills.

Half a dozen people have given you the correct answer, and you've argued with each one. 

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2 hours ago, Superluminaut said:

Could you share how exactly you do it?

I don't overbuild my rocket.  The Launch TWR is quite low (The rocket that put us on the Moon had a 1.2 TWR), and then as I ascend depending on the rocket and how good of an ascent I managed, I throttle back, which will not hurt your performance in any significant manner.  You need your engines most right on the launchpad.  Then on to the second stage which is designed to be weaker.  Gravity losses are insignificant if you are making a proper turn along the way.  It's lateral speed you want to be gaining, not vertical speed.

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2 minutes ago, Gargamel said:

Well, since everybody else can fly their rockets without this issue creeping up, or if it does, they all realize it's a piloting issue, then it must be the games fault for having a bug that doesn't recognize your perfect skills.

Half a dozen people have given you the correct answer, and you've argued with each one. 

They don't know what they are talking about. This isn't the first time I've posted the question. Same order of event every time. First the knowledgeable, and then those who know show up, and then the thread dies. If you'd like to see the future of the thread look here. Sorry if I'm blunt, just annoyed that nothing has changed.

 

4 minutes ago, Alshain said:

I don't overbuild my rocket.  The Launch TWR is quite low (The rocket that put us on the Moon had a 1.2 TWR), and then as I ascend depending on the rocket and how good of an ascent I managed, I throttle back, which will not hurt your performance in any significant manner.  You need your engines most right on the launchpad.  Then on to the second stage which is designed to be weaker.  Gravity losses are insignificant if you are making a proper turn along the way.  It's lateral speed you want to be gaining, not vertical speed.

That describes the rocket in the video.

Just to help the thread along.

 

On 6/25/2015 at 9:41 AM, Red Iron Crown said:

I can confirm NathanKell's assertion. Drag is trumped by gravity, the sooner you can get accelerating horizontally the better. I've made some rockets for my payload fraction challenge that just barely make orbit, and only if they go fast enough in atmo to see the reentry effects. If I make a steeper ascent that avoids the effects it runs out of fuel. (This is for reasonably aerodynamic designs, it might change if the rocket is severely draggy.)

As someone once put succintly, if a bit simplistically: Vertical speed is eventually lost to gravity, but horizontal speed is yours to keep forever.

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9 minutes ago, Superluminaut said:

That describes the rocket in the video.

No, it doesn't.  I'm not stupid, I know a low thrust launch when I see one, and that isn't one.  The speed that thing got off the launch pad was likely around 1.8 to 2.0.  If you are going to be tossing fish stories then I'm done trying to help you.

We are a forum full of wannabe rocket scientists.  We aren't that naive.

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You do realize that the Shuttle had to throttle down at Max-Q? Real rockets are designed to deal with ascent heating, either with heat tolerance, throttling back at key times, trajectory planning, or a combination thereof.

E: Looked at the video. Look at your acceleration, looks like about 18m/s2 off the pad. That's about 1.8g, or a TWR of 1.8. A Mainsail at full throttle on a rocket that size? Um yeah, that'll do it. My launches start to see some mild heating effects at ~35km, disappearing at 40-45km, depending on how well I managed the turn (rarely even close to perfect).

Edited by StrandedonEarth
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Kerbin is really small, so you get plasma more often during launch than you see in real life. I've noticed that when I launch in Real Solar System I get fire much less often. So yeah, giving your ascent a lower acceleration would probably be the best way to avoid that, unless you want to make Kerbin bigger.

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There are three issues here.

First, the visual effects are intentionally exaggerated, because the orbital speeds are so low. If we want to see reentry flames when returning from LKO, we will also see flames during shallow ascents.

Second, we have a 80% scale model of Earth's atmosphere on a planet 9.4% the size of the Earth. Our ascent paths are necessarily shallow, and our rockets go faster than real rockets at comparable altitudes.

Third, our low orbits are really low. The ISS orbits at 400 km, which would be 320 km over Kerbin. Yet we routinely launch to 100 km, which makes our shallow ascents through the atmosphere even shallower.

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2 hours ago, cubinator said:

Kerbin is really small, so you get plasma more often during launch than you see in real life. I've noticed that when I launch in Real Solar System I get fire much less often. So yeah, giving your ascent a lower acceleration would probably be the best way to avoid that, unless you want to make Kerbin bigger.

Actually, it's not directly due to Kerbin being small, but it is related. In stock KSP, plasma effects appear at a speed somewhat slower than in real life, as if they were implemented realistically, we wouldn't see them as much due to the relatively low orbital speeds around the small Kerbin.

Ok looks like Jouni said most of what I was saying here.

Also: "no drag losses"

If you fly in an atmosphere, you will have drag losses, especially with pre 1.1(?) souposphere. Even with newer atmo though, that ascent seemed pretty shallow. The angle you're at at 6km is what I'm at at 10km. Note that I've been launching rockets since version 0.14, so I've gotten a good idea of what works and what doesn't.

I do In fact get plasma on some of my launches, but usually I'm at 20+ km, and it is neither substantial, nor does it last very long.

Edited by EpicSpaceTroll139
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Yeah... having read the entire thread I have to say that what everyone else has said is spot on. Rockets rarely if ever have (much less need) a TWR above 1.5 at launch. Reason for this is because of your exact issue; Mach heating.

Personally I feel they finally ironed it out since I haven't seen it during a launch in ages.

Some have noted that the smaller scale of Kerbin may be a factor but honestly it just means you have to adjust your ascent profile. Following a NASA approach will likely have the end of your gravity turn at if not past the height for space on Kerbin (Kermen Line). So to fix this you simply curve over sooner.

Ultimately it just comes down to a case of "you don't need more boosterz". When you see flames, it means your going too fast- not too fast for Kerbin; just too fast in general. 

Next time you watch a rocket launch and hear someone call out "Max Q"- that callout is to prevent what your complaining about. 

A personal inference based on this thread; I'm just going to take a stab and say that @Superluminaut doesn't want help; he wants a change so it fits his play style (which I can guess is gunhoe and careless). That said, I don't mean that as an offense- it's just a guess based on what I'm reading.

Just as a notice; considering the majority of the community seem to be able to get around this issue, the likelihood of Squad fixing it is slim. Especially since the solution Squad will provide- is the same information we've already told you. They'll tell you that not because their lazy or heartless, but because that's the truth and it's how real rocket science works.

Edited by ZooNamedGames
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The "fix" is to realize it's that way for a reason and to follow the advice of the people in this thread regarding slowing or altering your ascent. A solution to the problem would be to install RSS, possibly wIth RO, and then expect your rockets to fly like real rockets, because Kerbin is a very different place.

Edited by regex
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17 hours ago, Superluminaut said:

They don't know what they are talking about. This isn't the first time I've posted the question. Same order of event every time. First the knowledgeable, and then those who know show up, and then the thread dies. If you'd like to see the future of the thread look here. Sorry if I'm blunt, just annoyed that nothing has changed

I see!

Carry on then.  Ignore reality until you can find a crackpot to agree with you.  Then you can continue to suffer the same problems because you didn't change what you're doing, and physics does not care about your feelings.

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The most efficient ascent is usually ball-of-fire ascent. I'm not sure how that is debatable. If that's immersion-breaking, and you're not willing to do an inefficient ascent of your own accord, you could turn up re-entry heating. That way the most efficient successful ascent will not be a ball-of-fire.

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17 hours ago, StrandedonEarth said:

You do realize that the Shuttle had to throttle down at Max-Q? Real rockets are designed to deal with ascent heating, either with heat tolerance, throttling back at key times, trajectory planning, or a combination thereof.

E: Looked at the video. Look at your acceleration, looks like about 18m/s2 off the pad. That's about 1.8g, or a TWR of 1.8. A Mainsail at full throttle on a rocket that size? Um yeah, that'll do it. My launches start to see some mild heating effects at ~35km, disappearing at 40-45km, depending on how well I managed the turn (rarely even close to perfect).

Apollo couldn't throttle down those F-1 engines, so shut one off before max-Q (I know it shut one down, so I'm assuming before max-Q).

Most of the reasons for a hot launch involve SRBs.  I can't imagine using a mainsail for such a hot launch (mechjeb might do something funky like launch at 1.8 and throttle down before breaking the sound barrier, but I don't have the dexterity for it.  You still wind up with an overbuilt rocket).  You can also get the wrong ideas about launch TWR (for kickback first stage) by launching straight up (and using apogee to determine delta-v) .  Since you need horizontal velocity instead of vertical, you will get the wrong results.

Many of my designs have a lot of thrust on the first stage (kickback-based) and wimpy second stages (LV-909s, Poodles, maybe even LV-N).  If I'm "launching hot" it isn't because that would be best for an ideal second stage, but because it works with a second stage that takes a long time to circularize.  If you hate atmospheric effects, why aren't you following the "standard" launch at TWR=1.1-1.3?  It seems to work for most people.
 

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23 minutes ago, wumpus said:

Apollo couldn't throttle down those F-1 engines, so shut one off before max-Q (I know it shut one down, so I'm assuming before max-Q).

Pretty sure max-Q happened long before that engine was shut down. IIRC it was shut down to avoid exposing the crew to excessive gee forces.

E2: Yeah, at T+80 Saturn V experienced max-Q, at T+135 the inboard engine was shut down as acceleration neared 4 gees.

Max-Q is simply maximum dynamic pressure, it's an event and most, if not all, rockets don't do anything about it (E: actively do anything about it, the airframe will be designed around it). Lifters that can throttle their engines are pretty rare IRL.

Edited by regex
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