Why do cars/rovers flip so easily even when you are only steering ?

[Triop]

Well, the question is in the title.

Is it a gravity thing ?

Is there something I can do about it ?  (without mods)

[miklkit]

Right click on the rover and a menu comes up that allows you to adjust lots of things.  The settings need to be different from place to place and from rover to rover, but there are some general guidelines. 

Mine are unstable under braking so I move as many parts to the rear as possible and also set the friction higher in the rear.

Steering response can be adjusted to slow it down so you do not over correct and cause the rover to spin out and flip. 

That particular one has very powerful wheels on a very light rover and Kerbin has high gravity.  Ya, that thing is going to be a handfull until you dial it in.  I only use those wheels when going to extreme places like the Mun's North Pole.

[Zacspace]

Rovers in KSP are much faster than they seem. Try converting the speed you're trying to drive at from m/s into something more usual for automobiles like km/h or m/h. Then, if you're a driver, think about what would happen if you suddenly cranked the wheel in one direction or another at that speed. Now consider that in most places in the game it's going to be even easier to flip over due to lower gravity.

It would be hard to build a more stable rover than that in KSP without abusing the game in silly ways. You'll just have to tweak the wheels and slow down a bit.

41 minutes ago, miklkit said:

Mine are unstable under braking so I move as many parts to the rear as possible and also set the friction higher in the rear.

Generally, you'd want to set more of your mass forward to improve stability, same reason as for aircraft except you're dealing with friction instead of drag. It's the reason most consumer vehicles have their engine mounted up front. The part about friction in the rear is spot on though.

Super cars and formula one have their engines mounted more center for the same reason that fighter jets tend to be aerodynamically unstable, for tighter turns.

Now that I think of it though, I'm starting to wonder why drag racing cars are so back heavy.

[miklkit]

I'm talking about braking and more mass on the rear helps there.  Otherwise the rear wheels just slide and it starts tumbling.  I understand the thing about building it like an arrow, but I have no issues with stability on the flat or uphill while turning and braking are a mess.  The stock physics on rovers makes them act like drift cars so slow steering and understeer are what I use to stabilize them.

[Triop]

Ok, I'm still trying to figure this out (again), but I think the gravity points should be here, this works amazing when it comes to stability.

I haven't played this game for a loooong time so I'm learning again...

 

I believe these setting will give a rover more downforce.

 

Edited January 24, 2023 by Triop

[Nazalassa]

I suggest putting one or two R.A.P.I.E.Rs upside-down as low as you can -- they will lower your CoM. If it gets below the ground, it will prevent thr rover from flipping in nearly all cases.

[Triop]

On 1/21/2023 at 8:23 PM, Zacspace said:

Generally, you'd want to set more of your mass forward to improve stability, same reason as for aircraft except you're dealing with friction instead of drag. It's the reason most consumer vehicles have their engine mounted up front. The part about friction in the rear is spot on though.

 

Thank you, setting the mass more forward really helps.

This is still just a testcar, but thanks to the forward mass it's allmost impossible to flip it.

I still have to slow down for jumps, cause it's nose heavy now...

[Xheotris]

One major improvement you can make is to add a reaction wheel set to SAS Only mode. This will prevent it from tipping while holding W, and allow you to recover from small bumps easier. You can feather it on and off during jumps and such. And, in the worst case, you can set back to Normal or Pilot Only to flip it back over in low gravity.

[kerlon_kersk]

this game about rockets ) physic of rovers are crap. I hope in KSP 2 we will have better expirience with rovers

[MattMoney]

Might be worth it to turn off general SAS and instead have a reaction wheel set to SAS only, especially in low-g environments.
Also probably a good idea to limit your wheel speed, it's not hard (especially with small little rover-cars like yours) to go crazy fast and not realize it seeing as the game doesn't do a great job at conveying ground speed visually.

[jimmymcgoochie]

Rovers in KSP are deceptively fast- 50m/s is easily achievable using those wheels but that’s 110mph (176km/h) and suddenly applying full steering lock at that speed will probably cause a massive crash in anything bar a proper racing car with aggressive aerodynamics keeping it glued to the ground.

As for why it flips, a sudden force to one side (steering, braking or even accelerating) will cause the centre of mass to try and keep going as it was due to inertia (straight if turning, same speed if braking/accelerating); the CoM is always above the contact point with the ground (the bottoms of the wheels) so this induces a tilt that will quickly push the CoM outside the area of support provided by the wheels, so it tips over. Low gravity only makes this easier by reducing the pull on the CoM to bring it back down onto its wheels if it tips up onto one side and starts doing a wheelie of some kind.

A quick trawl through dashcam footage will show you numerous instances where vehicles hit from the side end up rolling over or trucks (artic/semi trucks, not pickups) going off the road and toppling on an embankment or slope because they have a relatively narrow width for their height compared to a car; KSP rovers are often more top-heavy than any of those so combine that with abnormally high speeds and it’s not surprising they tip over.

There’s also the power of reaction wheels which can be a hindrance and a help, but set the wheel controls to the arrow keys and not WASD so you don’t do flips when trying to accelerate and rover driving suddenly becomes a lot more manageable without having to faff around with reaction wheel settings that can prevent you from using them when you need them most.

[Rocket Witch]

If you override friction control and reduce it, vehicles will skid while turning rather than grip & flip.

I usually set it to half of the gravity of the body I'm driving on, ie. 0.5 for Kerbin or 0.1 for Mun.

Edited February 27, 2023 by Rocket Witch