Phantom forces

[Vertibirdo]

Hello everyone!

I have a question considering forces, applied to the object.

The problem is- i am getting some weird phantom forces.

I have made a winglet. It is properly aligned and everything. I have made sure, that no collision boxes overlap.

But still, when i speed up my craft on the runway, it starts to violently slip sideways, tear off winglets and crash. If i manage to bring it in the air, it behaves nicely, until the landing gear touch the ground. After that it loses control and slips sideways again.

Here is the link to the part.

https://www.dropbox.com/s/7m5vhzucyrs4d6j/TraCom.rar

Maybe someone has encountered that problem?

[Deadweasel]

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[TR]

[TD]I get it around the Mün, where a small lander craft has to work very hard to dock with the fuel station in orbit at about 20km. The lander just seems to be consistently shoved to one side, forcing me to compensate constantly with the thrusters just to keep dock alignment. Then, even after having docked, the whole ship will gradually try to spin off-axis, as if it were in atmosphere. and its orbit will become increasingly elliptical over time, resulting in an eventual escape from the SoI, or impact with the ground. Staged decouplers suddenly explode and zoom off-screen as if they had been ejected in atmosphere.

There's some kind of drag force being applied here, and it never used to happen before. Worse, it seems there's no real answer for what causes it or how to fix it. I've seen responses that indicate any orbital velocity under 750m/s can result in this phenomenon (krakensbane), but that doesn't really make any sense to me, because that's above escape velocity from the Mün, and I've had massive multi-part ships orbiting anywhere from 12km to 50km up, moving at about 500m/s without issues before.

Perfectly fine and stable for more than 2 years of game time

Over 1 year in orbit without issues here, too.

Now this one, much smaller and with a smaller part count, is experiencing the drag issues...

Notice the periapsis of 14,214. It was at 12km originally. The elliptical orbit is my own doing, experimenting with getting up to 800m/s (before discovering that was beyond escape velocity), but now the PE has risen of its own accord due to whatever weird drag is being applied. :/

Even worse, the effect doesn't seem to be attached to any particular ship. When it first showed up, I had just assumed orbit about the Mün with this station

The four landers are attached at the lower ends of the crew compartments. Originally, the plan was to fly out there, then assemble the station on-orbit with the landers, moving the crew compartments up to the lower four-way dock near the top. The landers are kept stable with a decoupler linked to the main vessel with a strut. It was when I initially staged those decouplers that I saw the weird "explode and zoom away" effect, followed by the landers all drifting away sideways. Even after I stopped their relative motion, they'd just eventually resume their sideways drift, accelerating as they went.

Thinking the problem was with the ship, I sent the one lander with crew down to the Mün surface, along with another automated one, then de-orbited the rest of the vessel.

Then, I went back to the VAB, re-designed the thing so that it didn't need to be assembled later, and removed the resulting extraneous parts, including the strut-linked decouplers.

When I got back to the Mün with it, all seemed to be okay at a glance, but bringing the crewed lander back up, I saw it drifting sideways again. NavyFish's docking indicator was twitching badly; certainly far more than it should have been with those small and stable landers.

Something has changed in the persistent file to cause this, I'm sure of it, but I'm completely at a loss as to what setting I should be looking at as a potential cause.[/TD]

[/TR]

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