Why is my lander tipping?

[annallia]

Ok so I sent a few Kerbals to the Mun. I picked however a rather bad spot to land, turned out to be the side of a hill (never tried landing while dark before) and my initial lander tipped as it touched down sending the command pod down the hill a little ways, all the while being chased by the main bulk of the lander!

I mounted a rescue mission for my kerbals, designed a new rocket with a new lander capable of landing on an incline safely. I then launched a refueling satellite into Munar orbit for the lander to refuel before making its trip home (its 22 tons with all the fuel burned off). On the way there I realized I forgot to add parachutes to the lander and an important part of the staging that would drop a few tons of its dead weight so now it doesn't have enough thrust to land safely on Kerbal so decided what the hell it will be the start of a Munar base and I will send a new lander to pick up my kerbals later however...

Perfect landing. Switch to the Command Capsule to get my kerbals out and this happens

For whatever reason it suddenly hops 10-15 meters in the air and spins (yes RCS and thrusters are off). I reloaded my quicksave from when it first landed and it happened again, this time with me watching from the lander itself.

Edited August 2, 2013 by annallia

[UbioZur]

may be the center of mass of your lander is too far high up.

have you tried waiting with the command pod as an active ship to see if the lander tips?

any mechjeb smart A.S.S on maybe?

Try puting SAS on if it's off, so the it can use the torque to avoid it from tipping over.

Other solution would be to land it somewhere a bit more flat and use the kerbal jetpack to fly there. there is a nice few km distances for the jetpack.

[annallia]

Center of Mass is right below the hitchhiker can (or was in in the VAB), Unless unpacking the 2x4 solar panels on the top changed that it should still be relatively near there even without all the fuel.

All MechJeb stuff was shut down, I only used it to do the high orbit breaking burn then shut everything down and landed myself.

I did try the SAS, no help whatsoever even when combined with the RCS.

It was stable on the ground, I had warped until there was some daylight to charge the batteries. I stopped the warp and went to the space center to switch to the command pod, it was just as I was about to send one of my kerbals on eva to move over to the new ship that it decided to flip itself.

There is a flat spot about 1.5 km away, it is where I intended to land the first time but was slightly off course (by first time I mean the first lander not the rescue lander). And while I will send my ship back up again after dropping some weight I won't need for the flat bit I would still like to know why this one decided to do a cartwheel for no apparent reason.

[Epthelyn]

Is it something to do with those lander legs? I stopped using the smaller legs after every landing resulted in them clipping into the ground at some point (usually as soon as I touched the ground) and flipping the craft.

If that's not it, there may be some other clipping part that is causing the problem.

[UbioZur]

Having the CoM even lower could help, but i think it's from something else.

It looks like it does flip when the ship load. Which I think does bring your ship a bit over the ground (to avoid collision problems with rounded saved position values) and since it's on a slope and the CoM would be in the middle as it touch the ground it would tip over (a small bounce could be enough). It's like when you have a plane with wheels at different heights and when you load it on the runway is fall on the ground and bounce a bit and sometime de-align itself from the center of the runway.

Usually those landing legs works great.

I would suggest two things:

- try to lower your CoM to the lower quarter of the ship to help stability.

- if you need to change ships that are within 2.5km (I think), use the next/previous ship key (default [ and ]) -> Faster and no reload.

- if the ships are further away than 2.5, go to the map view and double click on the ship you want to control to switch to it (avoid having to go back to the space center).

[annallia]

Is it something to do with those lander legs? I stopped using the smaller legs after every landing resulted in them clipping into the ground at some point (usually as soon as I touched the ground) and flipping the craft.

If that's not it, there may be some other clipping part that is causing the problem.

Would a ladder clipping into the ground be enough to do this? I had it extended before I switched to the command pod.

[Nurph]

The extended ladder bits don't have collision boxes so thats not your problem. I believe the issue is with those particular landing legs. When I took a look at the .cfg for the regular legs I noticed that they lacked the breakingForce and breakingTorque parameters, unlike the mini and large legs.

[Vanamonde]

The medium lander legs have always been catastrophically springy. Don't use them on anything but small probes.

[annallia]

I re-launched with heavy legs and put it in almost the exact same spot (still on the side of the hill just a little to the west of the first landing spot) and it stayed put even after switching craft and all that happy fun stuff so I am going to call this solved.

Thank you!