Flames During Launch?

[Commander Zoom]

Returning player here with a question.  I'm finally getting back into KSP, post 1.1.3, for the first time since 1.0 and the new aero model dropped.  So imagine my surprise and alarm when a seemingly routine launch, run by MechJeb in its default profile even, caused my test rocket to be shrouded in flames during the later stages of its ascent!  It made it to orbit just fine, with the temp gauges on the capsule and parachute not rising above orange, but...

Is this the new normal?  Are spacecraft now simply expected to be on fire going up, as well as coming down?  And if not, can anyone offer suggestions, MechJeb settings, etc etc to avoid this in the future?

[dafidge9898]

Is there no damage? It's probably just hypersonic aerodynamic effects. It happens all the time, assuming you go fast and low enough (even if low means 30km). 

[Commander Zoom]

No damage (yet), but it's not white shock cones, it's orange plasma.  And it's happening in the upper atmosphere - mind you, that is when I'm almost at orbital velocity, but again, didn't see that before.

[Palaceviking]

Just going a bit quick in the atmosphere I think.

I try to roughly add 1 mach per 10,000 metres.

Also farings are surprisingly good for this.

[Foxster]

They've gone a bit overboard on the effects now. I turn them down to near-minimum in the settings but it's still more than is realistic. Doesn't do any harm though, just ignore it and watch the temperature gauges. 

[surge]

The nasa shuttle, Soyuz and the chinese thing (HN1?) all do that on launch IRL. It basically means you're doing the launch most efficiently.

Non-manned/kerballed rockets blatently abuse this and need heatshields... or as KSP calls them: fairings. Because they launch faster and at a lower flight path angle for even more efficiency, they don't have to care that some squishy, fragile human is onboard.

You may have heard of maxq? that's mostly why they care about it (there are structural limits, but they are waaay more tolerant than the meatsacks sitting in them, usually).

 

Edited July 22, 2016 by surge

[Streetwind]

26 minutes ago, surge said:

The nasa shuttle, Soyuz and the chinese thing (HN1?) all do that on launch IRL. It basically means you're doing the launch most efficiently.

Non-manned/kerballed rockets blatently abuse this and need heatshields... or as KSP calls them: fairings.

They do? Is there video evidence? I've never heard of that and would love to see it.

P.S.: Fairings are also called fairings IRL

Edited July 22, 2016 by Streetwind

[surge]

I did a quick google before I wrote that, but was blindsided by american propaganda. If you have the time, it's not hard to find.

Basically, find any rocket launch that includes the whole thing, instead of cutting to commentators blathering like idiots when it's 1/2 way up

Also, artistic license is used in the 'fairings' case; they help with aerodynamics obviously, but they are usually shed more quickly than most people imagine; basically, 5-20 seconds after booster ejection. I keep forgetting to arrange the stages so it does that, to my great annoyance.

Edited July 22, 2016 by surge

[Streetwind]

I've been following rocket launches from all around the globe for five years now, and I've never seen any plasma effects during ascent. Admittedly, I've never seen a single broadcast that showed the front of the rocket after first stage separation either, so I have no basis on which to decide whether this happens or not... which is also why I was asking for video evidence.

Going to Google, the only references to such effects happening all come from KSP forum posts, or KSP subreddit posts. Nothing from real launches at all. But then again, Google only shows a small subset of results tailored to my surfing profile anyway, so that's not conclusive either.

I'll take this question to the science forums because I am still curious.

[Geschosskopf]

7 hours ago, Commander Zoom said:

Is this the new normal?  Are spacecraft now simply expected to be on fire going up, as well as coming down?  And if not, can anyone offer suggestions, MechJeb settings, etc etc to avoid this in the future?

It's normal if you don't be careful with your speed.  You only get the flames if you're going way fast in thick air.  To avoid this, limit the thrust of the lower stages.  I've found that if I keep the starting TWR at about 1.5 for any stages that will operate below about 35km, then I get little or no flames on launch.  And I can still make LKO on about 3300m/s.

Edited July 22, 2016 by Geschosskopf

[bewing]

Going as fast as you can on ascent can be very efficient -- it depends on which direction you are trying to go. Yes you will get harmless plasma effects.

[Norcalplanner]

Flames on ascent = harmless

Temperature gauges = getting close to harm

Exploding parts = slow down

Seriously, I did a whole series of tests in the thread below, and reached some significant conclusions.  I just ran some more tests tonight in a stock system size, and the conclusions are largely the same - namely, launch between a TWR of 1.5 and 1.9, and crank it over hard (10+ degrees) as soon as you leave the pad at higher TWRs, then switch to prograde lock.

 

[bewing]

I would love to switch to prograde lock -- but in 1.1.3 it's sooooo noisy that it messes up my ascent, causes SAS to flicker into "rotating" mode, wastes my fuel and electricity, and just generally does naughty things. Gotta get some better smoothing on those SAS steering inputs in 1.1.4.

[Norcalplanner]

3 minutes ago, bewing said:

I would love to switch to prograde lock -- but in 1.1.3 it's sooooo noisy that it messes up my ascent, causes SAS to flicker into "rotating" mode, wastes my fuel and electricity, and just generally does naughty things. Gotta get some better smoothing on those SAS steering inputs in 1.1.4.

I should have clarified that I don't use the stock buttons - I always use the SmartASS buttons in MechJeb.  Much cleaner/smoother/better with more options, like being able to lock to surface velocity prograde plus or minus any number of degrees in any axis.  Very useful in RSS when you have a low TWR upper stage, so you can tell SmartASS to add +15 degrees to your prograde hold.

[bewing]

1 minute ago, Norcalplanner said:

I should have clarified that I don't use the stock buttons - I always use the SmartASS buttons in MechJeb.  Much cleaner/smoother/better with more options, like being able to lock to surface velocity prograde plus or minus any number of degrees in any axis.  Very useful in RSS when you have a low TWR upper stage, so you can tell SmartASS to add +15 degrees to your prograde hold.

Yeah, I was just reading your other thread. For now I gotta keep my main game stock for bugtracking purposes.

 

[Norcalplanner]

Just now, bewing said:

Yeah, I was just reading your other thread. For now I gotta keep my main game stock for bugtracking purposes.

 

Well, you can simulate it pretty well by engaging SAS and adjusting your attitude manually during the ascent.  Takes a bit more work though.

[bewing]

4 hours ago, Norcalplanner said:

Well, you can simulate it pretty well by engaging SAS and adjusting your attitude manually during the ascent.  Takes a bit more work though.

Heh. Well, not with my rockets. Try to steer any of mine and you'll be lucky if they only RUD and blow up. The knife edge of stability is where you find the best efficiency.

[Alshain]

On 7/22/2016 at 1:39 AM, Commander Zoom said:

No damage (yet), but it's not white shock cones, it's orange plasma.  And it's happening in the upper atmosphere - mind you, that is when I'm almost at orbital velocity, but again, didn't see that before.

Your speed is too fast, too low.  If you do a real gravity turn with a typical TWR, that won't likely happen.  MechJeb flies in a standard pattern, which assumes around 1.5 sea level TWR (which is typical).  If you have 2+ TWR, you are going to be going faster while lower in the atmosphere.  Of course with the new aero, you don't need MechJeb at all to have the rocket fly itself.  You can now do a real gravity turn with SAS off and sit back and watch without touching the controls.  It's a bit challenging to get it set up right and if your TWR isn't right it won't work at all.  But once you get it started, it's hands off.

Edited July 23, 2016 by Alshain