What's going on with these rover wheels?

[cephalo]

Ok, lets examine why my latest, really expensive project failed. I tested this design on Kerbin, and it worked fine. The idea was to use the lander legs to push the docking port up to a uniform height for surface docking in the standard way. So, I designed the legs to reach down lower than the wheels as in this picture in the VAB. You can see that the feet are a good distance lower than the wheels:

On Kerbin this design tested fine, presumably because the weight of the craft pushed the wheels higher in relation to the legs, but on Minmus, this happened:

As you can see, my extended legs are now floating very far above the wheels, completely ruining the design. This won't dock with anything on the surface.

This is actually not the only problem. I'm not sure why, perhaps because I designed this in the VAB instead of the SPH, the wheels on opposite sides from each other rotate opposite from each other, making it uncontrollable. (<-- Not sure about this actually, might just be uneven traction on Minmus.)This confuses me because everything was fine on Kerbin. I think the problem has something to do with the fact that before landing on Minmus, I had docked to another ship to transfer some excess fuel. I think the docking somehow messed up the orientation of the wheels.

Is there any way I can salvage this craft without spending my last dime on a do-over?

Edited June 17, 2015 by cephalo

[Starwhip]

If I am not mistaken, wheels in the VAB are shown with their suspension in the "stowed" position. Once a craft is actually loaded on the pad or runway the wheels will extend just a bit.

On Kerbin, gravity counteracts this force. On Minmus... well, not so much.

As for the messed-up orientation, well, I would try to switch to the KSC and back to the craft, or reload the game.

[cephalo]

Is there a way to put them back into the 'stowed' position? That's where I want them.

Also, after playing with it, I'm not sure about the rotation problem, It might just be that Minmus has no traction. In any case, I can slide around with RCS. It's the wheel height that kills the mission.

[MaverickSawyer]

Is there a way to put them back into the 'stowed' position? That's where I want them.

Also, after playing with it, I'm not sure about the rotation problem, It might just be that Minmus has no traction. In any case, I can slide around with RCS. It's the wheel height that kills the mission.

Yeah... A lot of downward thrust, or break the wheels.

[Finndibaenn]

did you try filling the tanks ? do you have a docking port on top you could use ?

Maybe if you make it heavier by filling the tanks it would get lower.

I actually did a similar design on minmus too, but using MK1 and MK2 wheels, not the MK3 as you seem to have used.

Regarding your direction issue, did you try inverting the faulty wheels ?

Also I gound that reaction wheels can make a rover uncontrollable by applying torque when you want to turn (was usually in a perpendicular - up/down - direction in my case), disabling them may help too

[mhoram]

The orientation of the wheels depends on the part from which you operate the ship. Usually it is the pod of the ship or the command seat (with an EVA Kerbal) and may change by docking/undocking.

However there is a manual override: You can find in the context menu of docking ports and pods an option to steer the vehicle from this part.

Usually I place a dockingport or pod on the rover for exactly this reason and switch to it while driving and verify on the Spaceport before the launch, that it's orientation is correct.

The navball on your picture shows that the part you control the rover with has a wrong rotation. On the navball the sky should be on top.

Edited June 18, 2015 by mhoram