Spacecraft spins uncontrolled

[pmagarinos]

Hi guys! I am a fairly new player, but a very addicted one haha. I started playing KSP just by curiosity and now I can't stop playing. Anyways, despite I only have half my science tree unlocked on career mode, I decide to design a new "kinda" rover that could land and move across the surface of the moon. The idea is to carry the thing to the moon with a big rocket, cancel the horizontal velocity with the last stage and then descent only with the rover as vertical as possible, using the lateral engines to cancel gravity. 

As I said, I am new and is my first attempt to do something like this. I designed the module as balanced and symmetrical as I could but for some strange reason I cant figure out, when I test it (on Kervin) it spins uncontrollably and crash in a couple seconds. I used as much theory as I currently know, the center of mass is balanced and the impulse of the engines also (I believe?). 

The design is dumb I know, it is only a proof of concept I wanted to try, but if it is not working, clrearlly I missing some mechanic or concept. Images for reference bellow. Oh, and the last image you can see in which direction it rolls. Is like for some reason the front engines are pushing harder than the rest. I check several time and ALL part ar symmetrically placed. 

What am I doing wrong? I more interested on learn what mechanic I am missing than other designs, I want to learn to play and being able to design crazy ships by myself.

Thanks in advance! This is my first post like ever, so let me know If I need to change something.

 

Seeya!

 

 

[Regor]

If you are fine with getting a mod, KER is probably an awesome mod for this. Using it, you can find how much torque the engines exert on the object (with 0 being optimal). This makes it way, way, WAY easier to make skycranes. If you don't want mods, maybe try adding a big reaction wheel. That will provide its own torque, and if it is great than the torque the engines are exerting, it will stay upright.

Of course this means you may have to re balance your craft because of the change in center of mass, but in my opinion that is worth it.

Edit:The front of your craft has only two of the engines on, and not all four like in the back! Check your staging.

 

Edited April 15, 2020 by mabdi36

[James Kerman]

Welcome to the forum @pmagarinos, your question has been moved to gameplay questions and I think @mabdi36 has spotted the problem of asymmetric thrust.

[Superfluous J]

Based on that brown hue of the navball on the launchpad, it looks like your probe core may be upside down. Or, you're not controlling from it. You want the entire navball to be blue when sitting on the launchpad.

Edit:

1 hour ago, mabdi36 said:

Edit:The front of your craft has only two of the engines on, and not all four like in the back! Check your staging.

I missed this! That's likely the biggest problem for sure. But I'd still check that probe core.