Fairing Problems

[CoriW]

Hello,

So recently I've been having an issue with fairings and I'm just wondering if anyone else has had similar problems. Typically I setup my fairings in a 2 sided clamshell configuration and after MECO they get separated, at which point the second stage (which was inside the fairing) takes the probe the rest of the way to orbit. The problem that I've been having is that when I jettison the fairings, one side of the clamshell always gets stuck on the rocket which then causes a problem when it comes to decoupling the second stage. I use RemoteTech and kOS so all of my launches are automated. After the fairing separation, the program decouples the second stage from the first and ignites the second stage engine at which point (due to the stuck fairing) the probe ends up getting bumped into the inside of the fairing which makes the rocket tilt off to the side and have to try and recover proper heading.

Here is what the rocket looks like, does anyone have any tips to potentially resolving this issue?

[Majorjim!]

I bet your payload is too close to the fairing. Can you show is the inside of it? 

[CoriW]

5 minutes ago, Majorjim said:

I bet your payload is too close to the fairing. Can you show is the inside of it? 

Tried my best to get some pictures of it without the fairing pieces moving out of the way. I'll try making the fairing a bit bigger and see if that fixes it, here's the pictures.

[Majorjim!]

Hmm, that looks ok to me. An you are using clamshell release? Try maxing the separation force. 

[CoriW]

13 minutes ago, Majorjim said:

Hmm, that looks ok to me. An you are using clamshell release? Try maxing the separation force. 

Yes I'm using the clamshell release, currently I have the separation force set to 300. I've noticed that when I increase the separation force it just makes it get stuck more violently. Also I just did a test in which I made the fairing obnoxiously large and took a gif of the problem in action. (Ignore the strangely placed plume coming from stage 2 engine)

EDIT: Huh, so previously whenever I'd raise the separation force it'd just sort of pull the rocket to the side more when it got stuck, but I had never tried just straight up maxing out the separation force at 1000.. Here's the result of 1000 separation force, but notice how even though the fairing actually comes off now it still seems to pull the rocket up slightly.

Edited July 10, 2016 by CoriW

[Goody1981]

I have had this problem too - completely destroyed the undeployed solar panels on my Duna probe. 

As @Majorjim, upping the separation force helped. The other thing I did that also helped was using a payload adaptor, as I think the problem occurs near the bottom of the rocket. Also, since the problem is reproducible (ie no matter how many times I reloaded the exact same thing happened on fairing separation) I now always test them on the launchpad with hacked gravity just to make sure they separate cleanly. 

[Majorjim!]

Just now, CoriW said:

Yes I'm using the clamshell release,

Great gifs man, very helpful! So max force helps a little, that's good. The jolt may just be the way Squad fairings work, ie, not very well. 

[Chakat Firepaw]

A diagnostic question:  What happens if you roll the rocket 90 degrees before jettisoning the fairing, (i.e. so they go off to the side rather than the top and bottom)?

[CoriW]

9 minutes ago, Chakat Firepaw said:

A diagnostic question:  What happens if you roll the rocket 90 degrees before jettisoning the fairing, (i.e. so they go off to the side rather than the top and bottom)?

Huh, I can't believe I didn't think of that.. That fixed the issue completely, I'd assume that it was the force of gravity that was causing the issue since the one that got stuck was always the one on top. Thank you.

[Emoss55]

Instead of rolling the rocket, just rotate the fairing in the VAB.

[CoriW]

36 minutes ago, Emoss55 said:

Instead of rolling the rocket, just rotate the fairing in the VAB.

Yup, that's what I ended up doing.

[Dunbaratu]

I always have this problem with stock 2-sided clamshell fairings.  I usually just fixed it by going with a 4-sided fairing.  It seemed to me like it was related to having a curved thing covering a 180 degree arc wedged in between the fairing ring and the decoupler that did it.  Making it cover a smaller arc (by using 4-part fairings so each part is only 90 degrees of arc) seems to keep it from getting stuck.