Viewing Nav Waypoints during Landing

[Gordon Fecyk]

When KSP 1.2 came out, Scott Manley brought up the concern of having to rotate a craft back and forth to see navigation waypoints on the nav ball. I thought I'd be clever and try mounting a probe body backwards on top of a crewed command pod, and see if I could land by pointing 'prograde' while controlling the craft from the backwards probe. No such luck; the craft would pitch wildly and then accelerate upward.

I haven't yet tried rotating the backwards-mounted probe 180 degrees around its axis to see if I can get a 'prograde' vector that was actually retrograde. I'll try that when I'm home next.

Aside from mods, has anyone come up with a clever way to view these waypoints while flying retrograde?

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[bewing]

Generally, this happens when you have engines that are gimballed or thrust vectored, and the core you choose to work from is on the wrong side of the CoM. Because the engine is on the other side of the CoM, the SAS system tries to turn it in the opposite direction of the reaction wheels and aerodynamic surfaces. Often this is not what you want, and all 3 of these inputs fight each other. The first easy trial solution being to disable the thrust vectoring/gimballing.

If you want to see this work in a simpler environment, try putting a ship in space. Put some reverse-facing gimballed engines at one end. Activate the engines, and then start switching between various SAS targeting modes, and watch which direction the engines swivel. They will probably always swivel the wrong way.

 

[Spricigo]

14 minutes ago, Gordon Fecyk said:

 I thought I'd be clever and try mounting a probe body backwards on top of a crewed command pod, and see if I could land by pointing 'prograde' while controlling the craft from the backwards probe.

 

This is supposed to work. Maybe you just rotated along the wrong axis and switched right/left instead of up/down?

[Gordon Fecyk]

23 minutes ago, Spricigo said:

This is supposed to work. Maybe you just rotated along the wrong axis and switched right/left instead of up/down?

I could fly the ship by hand easily enough. It was when I tried enabling prograde hold in SAS, while controlling from the backward-mounted probe, that the ship would pitch in the wrong direction.

Before launch of this oddity, I changed the "Control from here" setting from the pod to the probe to make sure the nav ball pointed up or down as I intended. That much worked. I didn't pay attention to the other angles though.

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[Spricigo]

Maybe (I confess I'm guessing here) the Command Pod its trying to apply SAS according its own orientation instead of the active control point. Try to disable SAS in the command pod.

after that I’m out of ideas

[Gordon Fecyk]

1 hour ago, bewing said:

Generally, this happens when you have engines that are gimballed or thrust vectored, and the core you choose to work from is on the wrong side of the CoM.

This actually makes sense. Though it would make design rather interesting to put a probe core on the other side of a fuel tank. I have ideas now, and will return after some playtime.

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[Gordon Fecyk]

6 hours ago, bewing said:

first easy trial solution being to disable the thrust vectoring/gimballing.

That did it.

I'll need to experiment with placing probe cores around the body of my craft, or simply rely on more reaction wheels. The cores I'd want to use have included reaction wheels most of the time, so I can rely less on engine gimballing.

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[bewing]

You can also use an action group to temporarily toggle the thrust vectoring while you are using the second core -- and just make sure you fly straight while you are looking backwards over your shoulder for waypoints.