It's funny, people keep arguing about how this is super intended, when
this has been already posted.
I think all Russian cold war planes are designed to work with non-infrastructure, and take off/land on dirt and snow runways. I know for certain MiG-21 does this, because the Vietnamese hid them in hut villages, then used the local dirt "road" and rocket boosters to get in the air and shoot mans.
Grass in DCS is super buggy. You can drive over it fine, just don't ever allow the MiG to stop, because then not even 100kN of thrust will get you out.