Rover Stability

[MajorGosnell]

https://youtu.be/NiMLlrQ3LzY My Very First Rover in career mode.

The Question is how do i stabilise her turning?

Answered,needed to widen my wheel base.

Thanks for the tips.

Edited November 5, 2015 by MajorGosnell

[Foxster]

You want the wheel base as long and as wide as possible, much more than that craft currently has. You also want the centres of gravity and thrust lower too, at or below the axles will be good. Then turn on SAS.

[Tex_NL]

I am seriously NOT surprised your rover is unstable. The only thing that does surprise me is that you don't see the problem.

Your rovers wheelbase is WAY too narrow. Your rover needs to be wider or lower. Preferably both.

Edit: Ninja'd

[MajorGosnell]

Trouble is when i go to attach the landing gears(only steerable wheels i have ulocked) the angle snaps at a curve.If i put them on the side it is to high

[capi3101]

Yeah - you need a wider axle track, or that thing's going to flip over with the first small bump you hit (or if you try to turn at any kind of decent speed at all). Putting some kind of protective shielding around the mission critical bits (i.e. the cockpit) wouldn't be a bad idea either; girder segments in this case, but in general anything with a high impact tolerance. Ordinarily I would suggest driving in docking mode; in staging mode, the main directional controls are going to want to pitch your craft rather than turn it. In this case though, with the engine providing the thrust, it's best to ignore that bit of advice. You might also consider adding a reaction stabilizer if you've got access to them.

Might also want to consider using an engine with an alternator - that Terrier's not going to recharge your batts. Just saying.

Trouble is when i go to attach the landing gears(only steerable wheels i have ulocked) the angle snaps at a curve.If i put them on the side it is to high

Again, I'd suggest girders. Put them about where you want them vertically, then roll them (Q and E keys) in that position until they're parallel to the ground. Then add additional girders to widen out your wheel base. It may look like dreck when it's all said and done, but it should help your stability issues.

Edited November 2, 2015 by capi3101

[MajorGosnell]

you have me thinking about making a tank now

[Snark]

Trouble is when i go to attach the landing gears(only steerable wheels i have ulocked) the angle snaps at a curve.If i put them on the side it is to high

Just checking-- you are aware of the rotate-part widget in the vehicle editor, yes? That is, when you move your wheels out from centerline, the editor will rotate them out away from the vertical, but you can then use the rotator widget to rotate them back to vertical and get some ground clearance back.

Also, consider mounting the wheels on something other than the central fuselage. For example, you could add a couple of swept wings sticking out to the side and maybe angled slightly downward, and then mount the wheels out on the wings. Would give you a lot of stability.

[MajorGosnell]

i wasnt aware of that.Thanks

[Alshain]

Not really relevant to what you are doing, but I strongly recommend reassigning your Rover keys off WSAD (I usually use IJKL) since the WSAD keys also control the reaction wheel torque in your cockpit. It's not as important on Kerbin, but it may prevent unexpected forward roll on the Mun later on when using electric wheels.

More relevant to what you are doing, right click the rear wheels and disable steering (or better, use the wider gear that don't have steering), use only 1 center gear on the front like a plane with steering. It will help with control. Braking on the front should be tweaked down, too much brake and it will roll forward. The only reason to have 4 wheels (or more) wheels instead of 3 is for power. Since you are using unpowered wheels, that doesn't matter much and 3 is more stable than 4.

Also, your basic jet engine only needs liquid fuel and air and will last a lot longer.

Finally, you might reconsider the rover entirely. As it seems you may be new to the game, you might not have learned to build and fly (or more importantly... land) a plane yet, but your tech tree shows you have all the parts you need and you can get around a lot faster in a plane than a rover. Rovers are good for KSC science, but beyond that, they are very slow. No time like the present to learn to fly.

Edited November 2, 2015 by Alshain

[Fearless Son]

I believe that if you have those small, steerable, always-deployed wheels unlocked, you should also have unlocked the larger, fixed, unsteerable wheels, the ones that stick out diagonally from the hull. I would think of those as better options for your rover, because they tend to spread the wheels wider and allow the mass to be slung lower relative to them than most other wheels can. Granted, you will still need a few non-fixed tires for steering, but you only need a few of those.

The only reason to have 4 wheels (or more) wheels instead of 3 is for power.

To be fair, additional wheels (particularly of the delicate self-driving kind common to rovers) have practical reason to have some redundancy beyond additional power, and that is to allow for a certain amount of drive system failure without compromising the entire assembly. A six-wheeled rover can loose a wheel or two and still be functional (if not quite as optimally.) This is a particularly big concern with unmanned rovers which necessarily have no engineer capable of field-repairing damage caused by a rough spot in the terrain.

[MajorGosnell]

Oh i know how to get into orbit my planes are rubbish though so i decided to drive.

[MajorGosnell]

Quick Update Guys an Gals,i upgraded my design https://youtu.be/q5m58jO8Gu8 ,widened the wheel base and she handled well....up to when i decided to floor the accelerator.

[Kerba Fett]

One other thing you can do with small rovers to give them stability is to mount an RCS quad thruster on top. When the system is on the jets will fire automaticly to prevent wheelies when accelerating and the one on the outside of the corner will fire to prevent it from rolling. When braking use reverse as well as the brakes to make the front facing jet fire and prevent the nose from diving.

Of course you'll also need a monopropellant tank.

[Superfluous J]

All the brouhaha about the new turbines gave me an idea. Put a jet engine on the bottom of your rover and rotate it around do it's facing up. The COM of the jet engine will push your rover's COM down, possibly underground.

[capi3101]

Both Kerba Fett's and 5thHorseman's ideas are excellent, and have been done/proven in the past. Another option - ion propulsion for downforce. Same concept as Kerba Fett's idea. Couldn't tell you which idea is more efficient.

[DancesWithSquirrels]

Ion engines aren't going to be very useful in atmosphere - no thrust. I wonder if it might be good to have a jet engine mounted a bit high, angled down through the CoG, so that you get some downforce along with propulsion?

MajorGosnell - looking at your video, you're using the "Staging" control set. If you look at the lower left of the interface, under the green rocket icon, you should see a purple-ish soccer ball and blue-grey orbit icons. The purple one puts your controls into "Docking" mode, where W/S translate forward/back, and A/D yaw left/right. That has the advantage over the staging interface of not causing your reaction wheels to roll you forward, back, or onto your side (which I see happening in your video), just strict translation. It can help quite a bit.

I put the controls into docking mode, and turn on SAS to (try to) keep my rover level - it really minimizes flipping. Just tap 'F' to re-level the hold angle any time the slope under the rover changes, so you don't end up with the SAS trying to force a wheelie on a downslope.

[capi3101]

Ion engines aren't going to be very useful in atmosphere - no thrust.

True. Clarifying then - where do you intend to use your rover, OP?