All my rockets are tipping and unstable - even previous solid platforms.

[Xuixien]

My KSP installation got super buggy and slow, so I did a fresh install. Now all of my rockets tip over when I use MechJeb Ascent Guidance. Nothing has changed with the rockets - I am using solid, stable, dependable platforms that I've used for the past weeks. My ship turns to follow the ascent path and then just... keeps turning until they just flip. What's going on? I'm not doing another reinstall. I already have to do that once every 2 weeks.

Edited September 29, 2015 by Xuixien

[Motokid600]

Reinstall once every two weeks? Sounds like you have bigger problems then your rockets flipping. Do you run with any mods other then MJ? More info will probably be needed.

But for starters what's your ascent profile you have MJ set to? Make sure you have corrective steering turned off until the cruise stage of your launch.

[Xuixien]

Reinstall once every two weeks? Sounds like you have bigger problems then your rockets flipping. Do you run with any mods other then MJ? More info will probably be needed.

But for starters what's your ascent profile you have MJ set to? Make sure you have corrective steering turned off until the cruise stage of your launch.

I'm launching exactly the same way, with exactly the same settings, and exactly the same ships as before. I don't mess with MechJeb settings except the height and inclination. I turn everything else off except "Auto-Warp". I've always ran like this and never had any problems. For example I have a Soyuz replica from Tantares I built and I've launched it dozens and dozens of times, always flawless and stable - now it just flips end over end during the gravity turn.

And yes, I have to reinstall every 2 weeks because they client performance just degrades and I start running into bugs. I'm not the only one either.

Here's my mod list.

[Motokid600]

And without mechjeb? Try to manually pilot it to see what happens in order to see if its MJ or the craft giving you issues. You had to have changed something. Anything.

I can't really comment on your degrading performance issues. I'm on Linux64 so I don't have that issue. Not sure what could be causing that. Make sure to take a look at the stock bug fix modules. See if anything in there rings a bell. Get the one that disabled the temp gauge if you haven't already. It supposedly responsible for memory leaks.

Edit: Sorry I just noticed your mod list. Are you on the 64bit client? If not that's WAY too many mods and that is directly responsible for your degrading performance. Holy crap that mod lists makes mine look puny and I am on the 64bit client.

Even if you do have 64bit you should consider cutting back. There's so many variables in that list I wouldn't know where to begin. Also is that CKAN? Never seen it before, but that's another variable too.

Edited September 29, 2015 by Motokid600

[Harry Rhodan]

Here's my mod list.

Can MJ handle FAR without any additional plugins now?

[Motokid600]

Can MJ handle FAR without any additional plugins now?

Yea it's never given me an issue. Just can't limit to terminal velocity which you don't need in FAR.

[Xuixien]

Removed FAR. Issue resolved better. I have NO IDEA how FAR got into my mod list, I never use it.

Edited September 29, 2015 by Xuixien

[Motokid600]

Well... Lol. You should still be able to fly with FAR. You just have to tweak your ascent profile accordingly so the gravity turn is more gradual. You have to start turning at a few hundred meters if you have a decent twr.

And those performance issues. No way in hell you should have to reinstall every two weeks. Consider cutting back on some mods it'll help.

[Superfluous J]

Any suggestions we give you will be guesses. Any chance you could either (in my personal preferred order):

1. Take a video of your launch.
   
2. Take screen shots of your ship on the launch pad, in early launch, right at the time the problems start, and maybe one or two as it's spinning out of control.
   
3. Give us the .craft file
   

That last one is likely not super useful as you have so many mods installed that I do not, that it's likely I won't be able to load it. If you could make a "stock" ship that has the problem then I'll happily test fly it.

Edited September 29, 2015 by 5thHorseman

[Xuixien]

Launch recording

Craft

[Motokid600]

There it is. Your enabling the navball guidance. That's for reference for YOU to fly manually. Mechjeb is not in control. You want just regular ascent guidance.

PS: The automatic gravity turn is crap. Don't use it. Figure out what variables work for your rocket there.

Try this.

Turn Start - 0.5km. ( 500 meters ) The twr looked high so maybe even lower like a .35.

Turn Start speed - 85. ( I don't mess with this much, but it coincides with your turn start. Lower the turn start. Lower the velocity start.

Turn end - 60km ( if your using DRE. If not you can go for 40 or even lower )

Final angle - 0 ( unless your upper stage is weak then you may want to bump it up to 1 or 2 )

Turn rate - 50 ( the higher the twr the less turn rate and vice versa )

Edited September 29, 2015 by Motokid600

[Xuixien]

There it is. Your enabling the navball guidance. That's for reference for YOU to fly manually. Mechjeb is not in control. You want just regular ascent guidance.

Always used NavBall guidance in the past, never any issue in over a hundred launches.

Just tried it without NavBall guidance: Issue persists.

I think I'm just gonna uninstall and be done with this game. Stock is absolute .... and the bugs and inconsistent performance of both the client, the mods, and the physics is more trouble than it's worth. Adios.

[Harry Rhodan]

and the physics is more trouble than it's worth.

Well you seem to be launching with around 4Gs. That is just too much.

[Motokid600]

Na nevermind I saw you hit enable guidance. Again... Have you tried flying that rocket on your own?

And trust me when I say this. Don't hate the game. Hate the player. 9/10 it's user error.

The only other thing I can think of is what I said about not using the automatic turn.

And again try flying without mj to narrow the issue down. I remember back when I had Tantares I was having a lot of issues with the vernior thrusters. They were way too sensitive and had a massive gimbal range.

Try it without MJ.

Oh you have to much sea level thrust there. That'll hurt you big time. Unless you just threw that craft together for the video then ignore that last statement.

[Kryxal]

Overpowered and FAR too hard a turn ... limit your AoA to 5 degrees and your accel to 20 m/s^2 and see if that helps.

[Motokid600]

Thing is he's not getting to the point where too much twr would be an issue ( it will be at maxQ ) There's simply no control what so ever in that video. You can see the venior thrusters working, but.. there not. Could be a Tantares issue.

Again. The best thing you can do now OP is fly without mechjeb to see exactly what's going on.

Also just in general. Don't enable MJ until after the rocket leaves the pad. There's a bug in the ascent guidance that will jostle the gimbals really hard on lift off. Just let regular SAS control lift off. Then enable MJ.

Edited September 29, 2015 by Motokid600

[Harry Rhodan]

Thing is he's not getting to the point where too much twr would be an issue ( it will be at maxQ )

If the pressure is toppling him over and ending his flight that point pretty much is MaxQ.

[Superfluous J]

Thanks!

Your TWR is 3, or roughly 2x more than it should be. I'd lose half the engines or replace them with something less powerful. If you really want to leave it the same way, stay throttled down to half like stock likes to do.

Your rocket is very bottom heavy, which makes it want to fly backwards. Removing engines as above will definitely help with that.

Your payload is wider than the main rocket. This will cause it to have more drag than you want, also encouraging flipping.

You have no fins. I'd add some. But they're just to help, they won't actually FIX the problem.

- - - Updated - - -

Also, I know nothing about MechJeb but is the target marker on the navball supposed to JAM ITSELF TO THE NORTH when you hit 100m/s? Because that looks to be where your problems really start.

Edited September 29, 2015 by 5thHorseman

[Motokid600]

.

- - - Updated - - -

Also, I know nothing about MechJeb but is the target marker on the navball supposed to JAM ITSELF TO THE NORTH when you hit 100m/s? Because that looks to be where your problems really start.

It does when you have the turn rate set to 26 degrees. That's the problem here. My apologies it is an aerodynamic issue. He's using the automatic turn which is junk. On top of that he's going WAY too fast way too low.

[GoSlash27]

^ I agree with all of the above. It appears to be initiating the flip due to an overly- aggressive initial turn and excessive acceleration off the pad.

I just downloaded it and will try to fly it... if it will work on a stock install.

*edit*

"Contains invalid or locked parts". Sorry. It's a beautiful looking launcher.

Best,

-Slashy

Edited September 29, 2015 by GoSlash27

[cantab]

Mechjeb: Crashing your ships so you don't have to!

With a fairing wider than the stack and no stabilising fins at the bottom your rocket will be mildly unstable. That means you need to hold it close to prograde at all times. Inside the yellow circle should be fine. Mechjeb is yanking it over and then you get a classic aerodynamic flip.

As for why it didn't happen before, two options. Mechjeb should have an option to "limit AoA", use it. KSP also has a known bug with its physics.cfg file being missing or corrupted, which causes incorrect aerodynamic behaviour. You could have built rockets in that behaviour only to find they don't work when things are right.