Kerbal Space Program

I reproduced all this with some primitiv never flying plane, just consisting of cockpit, fuelparts and wheels, nothing more.

Building kerbal like extreme ("just make it bigger") stuff is impossible this way.

I think #13276 is the same issue, maybe related to #13080.

(Another post about this #13413)

Minmus base isn't moving as much as Mun base, but it's there (lighter base on Minmus, lower gravity, smaller planet)

Confirmed in version 1.2.2 on Windows 10 x64.

This issue makes takeoffs nearly impossible at times, making game play quite difficult, hence my changing the priority to Normal.

This issue may be related to the wheel bouncing issue here: http://bugs.kerbalspaceprogram.com/issues/10095

Large and extra large landing gear allows plane to slide on runway with breaks locked. (OK, so this bug was reported already, but it still exists in 1.4.3 and here is some more data)

Watch: https://youtu.be/7ZgRdm8ZrkU

Background:
I noticed some of my larger ships using the large landing gear (radially x8) in liu of landing struts had a tendency to slide around even with breaks on. I just assumed it was uneven ground, until I noticed this on the runway. I ran tests on the medium and large landing gear (x3) using a tiny plane, and had no problems. Then I created some heavy weight tests (1,800 tons) for the large and Extra large landing gear (x4).

Each was tested first at normal spring and damper levels, then at max. In all cases, the landing gear allowed the load to slide up to 1.2 m/s. I toggled the breaks off to build up a little momentum, then turned them back on and watched my speed slow which indicated the breaks were working (at least slowing it down). This leads me to conclude that if breaking action were to be applied continuously, the plane should eventually stop since there was no engines or RCS applying force. It was almost as if the buildings had some gravitational pull.

I tried increasing the extra large test to 8 landing gear, and this decreased the drift speed down to 0.2 m/s with breaks locked. I released the breaks and waited until reaching 0.8 m/s before locking them again, and the load quickly dropped back to 0.2 m/s. You would think that with more wheels, they would compress less and have less contact with the ground. The 4 gear version should probably be smashing those tires into the ground for even more friction.

Next, I allowed the 4 wheel version of the extra large to run off the runway and build up speed up to 10 m/s running down the slope. Then I locked the breaks and reduced it to 0.3 m/s before it then rose to 1.4 m/s on the grass. I also noted that the wheel stress never reached above 5.0 and the wheels appear to be vibrating.

Forget anything about the building having gravity. The pull seems to be to the right in all cases and I can do a complete circle. At no point does it apear to be leveling out or going up hill to slow down. It's like it's caught in a vortex or something. This bug is not restricted to the runway. It is a landing gear issue.

I thought that perhaps, because all landing gear are autostrut locked to heaviest part, there might be a problem in the loop for finding heaviest part (like a test for >= rather than just > ) so I decreased each of the larger tanks by 10% save for one, and that didn't seem to matter any.

So I do not believe there are any more tests that I can do from my end. Good luck on this one. Here are some potentially related bugs:

Bug #16952
Bug #18099

Since i restarted playing KSP and already run into the same problem seemingly even easier than at time filing this bugreport, i am reconfirming this bug with version 1.4.3.2152.

If i could, i would like to increase priority to this bug to at least high or even critical, since building large stuff, if plane or outpost, gets extremly unplayable at some size. I stopped playing this game because of such stuff, because you waste your time when everything large is nicely done, it's just crashing at some point.

"Luckily" you need some time to get to that point of beeing able to build those sophisticated things, but then your motivation goes down to hell in no time!

So, why even trying to play career, if at some point it's just over because of this bug, which i hope will die before its 2nd birthday (or lets say 3rd, respecting birth of gameversion).

...and btw. why should i buy any DLC before the Core Game isn't working at some point? Maybe i write another review on Steam :/

AlffromKerbal, I really think you should include save files of the ship that is sliding. From the pictures, we can't tell what your strut situation is looking like, nor the spring tension of those landing gear. It looks like you have the medium ones, but you also have some wheels.

I have run tests with a very large ship on both Mun and Minmus in various slopes. I also run 1.4.3.2152 without mods. The following parts in this ship require the Making History expansion:

S4-512 Fuel Tank
S3-S4 Adapter Tank
RE-J10 "Wolfhound" engine

As I am sure you probably won't be running these saves if you don't have the DLC yet, if you would like to upload one of your own saves with the vessel sliding on Mun or Minmus, I will be happy to take a look and see if I can find anything to help you out. As my tests reveal, the ship alone on a nearly flat surface doesn't slide on the LT-2 landing struts, so we may need to refine our description of the bug here regarding Mun and Minmus issues.

Engineer's report of remaining ship after all parts staged
Mass: 3,319.135t (fully fueled)
Dimensions(H,W,L): 32.8m x 27.2m x 27.2m
Parts: 513

LT-2 Landing struts:
Count: 32
Spring: 1.25
Damper: 2
Autostrug: Locked Heaviest Part
Rigid: Off
Parent: Modular Girder Segment XL (in a way that it can support the ship when landing gear are retracted after landing)

Craft: Massive LfOx station
Purpose: Provide refueling for 207,360/253,440 LF/Lox
Actions:

Gear: Landing gear and Kerbnet Access (to see the altitude of the ground)
RCS: Controls Verner engines, which use Lf/Lox
1: Solar pannels
2: Toggle converters, fuel cells, thermal cooling, and deploy/retract drills
3: Toggle drilling
9: Toggle Vector engines (x32)
0: Toggle Wolfhound engines (x4)

Test saves.zip:

Mun Slide 30 deg slope.sfs
Mun stable 12 deg slope.sfs
Mun stable 2 deg slope.sfs
Minmus slide 22 deg slope.sfs
Minmus stable 9 deg slope.sfs
Minmus stable 0 deg slope.sfs

Ok, i just put some parts together, made some screenshots and quicksaved.

Btw. i found some old backups, if you see a clue in now given savegame and it would be useful to have one with those moving outposts on other planets, i might check them out.