(Breaking Ground) Unpredictable Freezing Hinges

[Mars-Bound Hokie]

The title's self-explanatory, but here are the details.

 

I'm experiencing some trouble with the hinges in my XF-85 Goblin replica. More specifically, they have a tendency to freeze up while in action. Sometimes it's one hinges, sometimes it's both, other times I get lucky and they're both working properly - until they don't. Even when I revert to SPH and launch again, whether or not the hinges would work has become unpredictable.

 

• Cute, but I didn't design this just to give salutes in Air Force parades.
• For the record, my original plan was to have it launch from a stability enhancer - but each test ended in explosions.

 

• Here's what I have set up for both servos. As you can see, I didn't mess with the symmetry.

 

Could you please tell me how to fix it. If you want to mess around with it and/or provide a predictably working copy (one whose servos can be trusted to work every time), here's the craft file if you want to try it out for yourself.

• https://mega.nz/file/fL52CQLQ#1-We2O0mCHTyx6DXuppJ_yEjQ6kJLvw47aCDoTCp400
• I don't really care for takeoff stability, since it was originally designed IRL to be launched from a host plane. After I got both wings down, once I got airborne it flew very well.

 

Thank you all very much.

 

P.S. For the record, I made the wings fold since the real-life Goblin was designed to be stowed in a bomb bay and then deployed once the bomber was attacked by enemy fighters. That project ended up getting cancelled in 1949 due to:

• Too many failures in the "attach to the mothership" part during testing.
• Lackluster performance compared to other jet fighters.
• Development of aerial refueling technology for escorting fighters.
   

P.P.S. I based the general design somewhat off of fatology's pure stock copy of the Goblin. 

Edited July 27, 2023 by Mars-Bound Hokie
Grammar

[king of nowhere]

I'd suspect an issue with running out of electricity, robotic parts freeze if left without energy. but if it happens at launch, and only sometimes, it's unlikely to be the case.

[swjr-swis]

On 7/27/2023 at 1:40 PM, Mars-Bound Hokie said:

Could you please tell me how to fix it.

X-85 Goblin 2

Two things tried:

• Locking the hinges after unfolding, which I think you already did,
• Adding a pair of Jr docking ports to 'dock' the wings in place.

 

[Hotel26]

I took a look at the original craft, too, and, after reproducing the problem, I removed the auto-struts on the hinges and broke the symmetry.  No further evidence of the problem, but I didn't have the patience to do a Thousand Cycle test.  I'll leave that to @Mars-Bound Hokie.

Caveat: I did the work in 1.11.2.  I do suspect it was primarily the symmetry that was causing a hang-up.

Edited August 9, 2023 by Hotel26

[Mars-Bound Hokie]

On 8/9/2023 at 8:23 AM, Hotel26 said:

I removed the auto-struts on the hinges and broke the symmetry.

I did both, and the hinges started working properly. Thank you very much.

 

• In addition to the wings deploying and retracting on command, they were doing so CONSISTENTLY after each launch. In other words, I didn't have to cross my fingers hoping both hinges would work properly each time.

 

• A mid-air wing retraction test
  • SUCCESS

 

For more details on how the plane performed, check out this post on the National Museum of the United States Air Force replica showcase.

• If you want to comment on its performance, or if you have replicas of your own to show off, feel free to do so. Thank you.

[Kimera Industries]

YES THANK YOU! I am having the exact same problem (With all my hinges) It happened on/off, but while trying to make a Kerbalized Starship, the hinges would just not work. Sometimes one would go, or none, or the working one would switch- I'll have to try this, and I'm pleased to hear it worked so well.

Also: I have a complete Aircraft of the World collection. It's super nice, and it's given me loads of KSP ideas, which is mostly a good thing. One of my favorite bits is "Weird and Wonderful," and it contains the Goblin. It's a very odd and useful idea, and it's super cool to see you replicating it! Personally, though, my favorite from that section is the XF-2Y Sea Dart or the Mayo Composite. (Note: They are seaplanes, do not attempt or else sanity will break, cause water is unsophisticated in KSP)

[Kimera Industries]

It worked! Merely disabling autostrut was enough and I went through many old craft I had given up on because the hinges wouldn't work. For example, my Osprey landed on the Vab, and the Admin building. Everyone seems to forget it has a helipad.