Violent SRB shaking in 1.1.1

[Bloody_looser]

Well, I've got a really trusted rocket design. It looks like that.

 

Now it is shaking violently right after launch and disintegrates. Yep it worked just fine in 1.1 and before.

 

What happened?

 

Broken craft from previous version

https://www.dropbox.com/s/zg01hy15d7sk5cz/Researcher%20prot_%20early_broken.craft?dl=0

Flyable craft with lower stage rebuilt in 1.1.1.

https://www.dropbox.com/s/gxct84acw13lk27/Researcher%20prot_%20early.craft?dl=0

 

Edited April 29, 2016 by Bloody_looser
Uploaded crafts

[Joco223]

Try removing some SRBs, the rocket seems to accelerate really quickly.

[ElWanderer]

I don't see any struts between the SRBs and the tanks they're attached to. Are there some well-hidden ones? If not, putting in some would be my recommendation. Edit: on looking at this on a larger screen, I can indeed see some struts.

I can see your payload poking out through the fairing. I thought that was meant to get auto-strutted from v1.1 onwards... perhaps try recreating the fairing?

Edited April 29, 2016 by ElWanderer

[Terensky]

1 hour ago, Bloody_looser said:

Well, I've got a really trusted rocket design. It looks like that.

 

Now it is shaking violently right after launch and disintegrates. Yep it worked just fine in 1.1 and before.

 

What happened?

 

Probably they fixed something and broke something else!

I've similar issues with some of my rockets which were rock (no pun intended...) solid in 1.1 and wobble a lot in 1.1.1, even simple designs as this:

Perhaps they loosened the joints a little to fix the wheels, I don't know, I'm not expert.

 

There's a bug report here:

bug 9583

let's hope they investigate and fix it.

Edited April 29, 2016 by Terensky
typo

[RW-1]

Or reduce the thrust a bit, strut them suckers ...

[Terensky]

2 minutes ago, RW-1 said:

Or reduce the thrust a bit, strut them suckers ...

Don't want to sound harsh, and I apologize if so, but people here seem not to understand these designs worked perfectly fine in 1.1...

[RW-1]

8 minutes ago, Terensky said:

Don't want to sound harsh, and I apologize if so, but people here seem not to understand these designs worked perfectly fine in 1.1...

Yup, we all do.  Ch ch ch ch ch ch changes (I miss David Bowie)

I also don't want to sound harsh (you didn't), I already was on the no sale thread, but just because it worked in 1.1, and now doesn't in 1.1.1 means it wasn't you or your design, but changes made for any number of variables in the patch, and now you might have to:

make a bug report

or make changes to your design to cope with said changes in physics, atmospherics, who really knows except squad?

 

Reminds me once of a student, finally mastered hovering the helicopter, then the next day I took him up in it with some wind ...

Edited April 29, 2016 by RW-1

[Terensky]

22 minutes ago, RW-1 said:

I also don't want to sound harsh (you didn't), I already was on the no sale thread, but just because it worked in 1.1, and now doesn't in 1.1.1 means it wasn't you or your design, but changes made for any number of variables in the patch, and now you might have to:

make a bug report

or make changes to your design to cope with said changes in physics, atmospherics, who really knows except squad?

Infact.

Someone already made a bug report that may be related to this, I posted the link up in this same thread.

Since I could not find in the changelog of 1.1.1 something inherent to this behaviour, I can just assume it's a (accidentally) introduced bug or misbehaviour of some sort.

Edited April 29, 2016 by Terensky

[Kerbol Macrosystems]

This seems like the time to mention that you can search moar in KSPedia, though they don't seem to mention that Moar is the god of reaching orbit.

[Alshain]

1 hour ago, Terensky said:

Don't want to sound harsh, and I apologize if so, but people here seem not to understand these designs worked perfectly fine in 1.1...

An unsound design is and unsound design, whether it worked in 1.1 or not.  The top of his SRB's are not strutted and are flexing on the decoupler, it's pretty obvious in the second screenshot.

Asside from that, it is a very over-built rocket.

[Terensky]

15 minutes ago, Alshain said:

An unsound design is and unsound design, whether it worked in 1.1 or not.  The top of his SRB's are not strutted and are flexing on the decoupler, it's pretty obvious in the second screenshot.

Asside from that, it is a very over-built rocket.

I may agree with you about Bloody_looser's rocket. But about the one I posted a picture of, it doesn't seem to me neither over-built, nor that it should need struts.

You sure have all the reasons in this world in pointing out the design flaws of Bloody_looser's (and even mine), but the fact is that in 1.1 these worked and in 1.1.1 they don't, and in the 1.1.1 changelog there's no mention of any modification about rockets' behaviour: at least, I could not find any, though some entries might arise a suspect, but still, I'm not expert.

[Luke Skycrawler]

Remove the fairing and see how it flies.

[Alshain]

12 minutes ago, Terensky said:

I may agree with you about Bloody_looser's rocket. But about the one I posted a picture of, it doesn't seem to me neither over-built, nor that it should need struts.

You sure have all the reasons in this world in pointing out the design flaws of Bloody_looser's (and even mine), but the fact is that in 1.1 these worked and in 1.1.1 they don't, and in the 1.1.1 changelog there's no mention of any modification about rockets' behaviour: at least, I could not find any, though some entries might arise a suspect, but still, I'm not expert.

Yours has no fairing.  Most likely your violent shaking is due to air pressure, which isn't the same as his.  You are also using active winglets, are they disabled?  A rocket that size probably doesn't need fins at all but 4 active winglets will often work against your engine gimbal.

You can complain about how they worked in 1.1 or you can fix your design and have them work in 1.1.1.   It seems to me the latter is the easier route.

Edited April 29, 2016 by Alshain

[Bloody_looser]

Are y'all blind? SRBs are strutted on top and bottom.

2 hours ago, Terensky said:

There's a bug report here:

bug 9583

let's hope they investigate and fix it.

Thx, will provide moar info to the tracker.

40 minutes ago, Alshain said:

Asside from that, it is a very over-built rocket.

Like it's a bad thing.

 

P.S. The rocket doesn't even have parts, mentioned in 1.1.1. changelog. Phantom forces are not a 'change'.

[Alshain]

22 minutes ago, Bloody_looser said:

Are y'all blind? SRBs are strutted on top and bottom.

They appear to be in the first screenshot, but in the second there is at least one that isn't.  If you are using symmetry, sometimes it fails to attach.

22 minutes ago, Bloody_looser said:

Like it's a bad thing.

It can be, if a rocket is too powerful, you get a distinct loss of control through the atmosphere.  Not saying that is the issue, but that is one powerful rocket for such a small payload.

Post your craft file and I'll see if the same issue is happening on my PC, none of my lifters with radial boosters are doing it.

Edited April 29, 2016 by Alshain

[Bloody_looser]

Well, I ran further tests.

Some phantom lifting force applies to SRBs sideways (and all over the place).

 

Rebuilding exactly the same the lower stage from scratch solved the issue. So we have .craft file incompatibility there.

And it's kinda not good, y'know, we're kinda in 'released' game.

Edited April 29, 2016 by Bloody_looser

[Violent Jeb]

SRBs are criminally low power. pretty sure you could lift that entire thing with 4 lvt-30s or a mainsail.  and then you could add 2 SRBs for show.

Rockomax needs a class action kerbal lawsuit for failing to deliver things to space with SRBs is what I think.

7 minutes ago, Bloody_looser said:

And it's kinda not good, y'know, we're kinda in 'released' game.

Game was "kinda" released when it was in early access. I think its going to be "kinda" released for some time. that is generally well known information at this point.

Edited April 29, 2016 by Violent Jeb

[Alshain]

7 minutes ago, Violent Jeb said:

SRBs are criminally low power. pretty sure you could lift that entire thing with 4 lvt-30s or a mainsail.  and then you could add 2 SRBs for show.

Rockomax needs a class action kerbal lawsuit for failing to deliver things to space with SRBs is what I think.

Game was "kinda" released when it was in early access. I think its going to be "kinda" released for some time. that is generally well known information at this point.

They are also cheap, that makes them good for augmenting lift and range capabilities of an existing lifter.  I've found in my lifter designs that the SRB's scale nicely.  I have designs up to 10 ton payload capacity that just add larger SRB's as they go higher in capacity (2 SRB's and 2 LFO stages stacked).  After that, might as well go with Size 2 as it will end up cheaper using a Poodle/Skipper center stack.

Edited April 29, 2016 by Alshain

[AlamoVampire]

@Bloody_looser From what I can see (on iPad at least) only the inner core of SRBs are strutted. Try running a ring of struts on the outside srb to srb in an X fashion. Should lock it down. And fwiw more power sometimes is bad. Sometimes.

[Violent Jeb]

3 minutes ago, Alshain said:

They are also cheap, that makes them good for augmenting lift and range capabilities of an existing lifter.  I've found in my lifter designs that the SRB's scale nicely.  I have designs up to 10 ton payload capacity that just add larger SRB's as they go higher in capacity (2 SRB's and 2 LFO stages stacked).  After that, might as well go with Size 2 as it will end up cheaper using a Poodle/Skipper center stack.

Yes i know they're substantially cheaper. I'm just saying that USUALLY, trying to accomplish orbit, with mass and part counts as the limiting factor (tier 1 facilities), SRBs pale in comparison to LFO, esp for dv vs. mass. They're great for keeping the initial stage with a decent TWR. but i'd never put a radial set of 6 on anything. If I need 6+ SRBs i'm just making things too complicated. No more jokes for me!

Edited April 29, 2016 by Violent Jeb

[Bloody_looser]

51 minutes ago, Alshain said:

Post your craft file and I'll see if the same issue is happening on my PC, none of my lifters with radial boosters are doing it.

Updated op with broken craft and the same working one.

[Alshain]

Just now, Violent Jeb said:

Yes i know they're substantially cheaper. I'm just saying that USUALLY, trying to accomplish orbit, with mass and part counts as the limiting factor, SRBs pan in comparison to LFO. They're great for keeping the initial stage with a decent TWR. but i'd never put a radial set of 6 on anything. If I need 6+ SRBs i'm just making things too complicated.

Well I agree there, the only time I use 6 SRB's is on Size 3 when there simply are no larger LFO engines.  I do use 4 SRB's in several cases though.  Using SRB's is still better than using radial LFO, because that is incredibly expensive.  I don't have any radial LFO stage on any of my lifters up to 120 tons payload, and anything larger than that I usually just break up into dockable components.

3 minutes ago, Bloody_looser said:

Updated op with broken craft and the same working one.

I see what you are saying now.  That does seem buggy, definitely not a strut or aero issue.  It's really strange.

[Terensky]

1 hour ago, Alshain said:

You are also using active winglets, are they disabled? 

No.

1 hour ago, Alshain said:

  A rocket that size probably doesn't need fins at all but 4 active winglets will often work against your engine gimbal.

Good to know, thanks.

1 hour ago, Alshain said:

You can complain about how they worked in 1.1 or you can fix your design and have them work in 1.1.1.   It seems to me the latter is the easier route.

Perhaps it would, if I exactly know what's wrong with it. Here's the craft file:

https://www.dropbox.com/s/xu5xzlazdfijfve/Rescue MKIId.craft?dl=0

Try engage SAS at launch, set it to prograde after having started the gravity turn between 70-100 m/s and see how much the engine's bell wobble... After a while the whole rocket wobbles. This didn' happen in 1.1.

And rebuilding a whole fleet of utility vehicles from scratch just to make them work again as they used to do before is a little irritating, to say the least.

Especially if you had to restart a career game after 1.1 broke your 1.0.5 gameplay.

34 minutes ago, Bloody_looser said:

Rebuilding exactly the same the lower stage from scratch solved the issue. So we have .craft file incompatibility there.

True, rebuilding the same exact rocket in VAB mitigated the issue for me, though did not solve it completely.

Anyway, lesson learned: backup KSP dir, so when a kew update come out (with Steam I can't opt out of auto-updates...) I will have something to revert to if things go wrong.

Edited April 29, 2016 by Terensky
right file re-linked

[Alshain]

Yeah, sorry Terensky, I realize the problem is worse than I thought after trying Bloody_looser's craft (assuming yours is the same issue).

I made a video of his craft.  None of my existing craft seem to do this.  It's quite odd.

 

[Terensky]

My issue is mainly due to engaging SAS in prograde. De-select it and the problems disappear (though, well, I'm not such a good pilot I can do without SAS).

The craft file I posted above has been rebuilt in 1.1.1 and the ship doesn't wobble as the 1.1 one, but the SAS strange behaviour persists (it didn't happen in 1.1 build 1230).

Edit:

http://forum.kerbalspaceprogram.com/index.php?/developerarticles.html/kerbal-space-program-patch-111-is-now-live-r190/&do=findComment&comment=1416

Well, maybe they're going to fix this too.

Edited April 29, 2016 by Terensky