Understanding navball yaw

[GroovyMike]

I've searched and found people asking why this happens, but no answers, so I'll post a new thread myself.

I've played flight sims and am fine with the navball when flying an aircraft/spaceplane. My issue is with the navball while launching a rocket.

Press A, or joystick left. The rocket's nose moves to the left/west, and the craft indicator on the navball moves to the left/west. Makes sense.

Press D, or joystick right. The rocket's nose moves to the right/east, and the craft indicator moves to the right/east. Makes sense.

Press W, or joystick forward. The rocket's nose moves away/north. Makes sense. But the craft indicator on the navball moves SOUTH. Huh?

Press S, or joystick back. The rocket's nose moves toward/south. Makes sense. But the craft indicator on the navball moves NORTH. What?

Why does yaw "work" and pitch is opposite? Obviously I could reverse this in the settings, but then I'd have to exit the game and switch the setting back when I wanted to fly a plane. I'm guessing there's some logical reason for this behavior, but I can't find it anywhere, and can't imagine any reason for it.

[peachoftree]

Are you sure you've got you self oriented around ksc? looking from the launchpad towards the vab is west. behind you is east. to the left is south and to the right is north

[mhoram]

Perhaps to give the rocket the same steering-properties as spaceplanes!?

There are several indicators on the Navball, but I don't know any of them under the name "craft indicator". Which one do you mean?

http://wiki.kerbalspaceprogram.com/wiki/Navball#Symbols_on_the_ball_instrument

Edited September 25, 2014 by mhoram

[GroovyMike]

Perhaps to give the rocket the same steering-properties as spaceplanes!?

There are several indicators on the Navball, but I don't know any of them under the name "craft indicator". Which one do you mean?

http://wiki.kerbalspaceprogram.com/wiki/Navball#Symbols_on_the_ball_instrument

Sorry, I'm referring to the level indicator.

[Kryxal]

In the launch position, you're looking straight up. "Right" is east, "Left" is west, therefore pulling "up" is south and nosing "down" is north.

[cantab]

The heading indicator is the wide V-shaped thing in the middle. That actually stays still, while the navball moves underneath it, like the artificial horizons on most aircraft.

When you start on the pad the compass directions on the navball are like this:

 S
W E
 N

(North is emphasised by a red line, by the way).

You might be thinking "wait a moment, north and south are flipped!". The reason is that you're effectively looking straight up at the sky, not down on the ground like with maps of Earth. You get the same effect on star maps, if you put north at the top east and west appear reversed, for the same reason.

With that in mind, A yaws to port, which is west in the default craft orientation. B yaws to starboard, which is east. W pitches down, which is north. And S pitches up, into an inverted attitude heading south.

[GroovyMike]

Are you sure you've got you self oriented around ksc? looking from the launchpad towards the vab is west. behind you is east. to the left is south and to the right is north

I apologize, as I've incorrectly described my situation. Let me try again. When I click launch, the game places me facing the flag pole with the VAB to my left and the ocean to my right. The navball is set so that 0 degrees is at the bottom, 180 degrees is at the top, 90 degrees is to the right, and 270 degrees is to the left.

Already that throws me off, because I'm used to a 2-dimensional compass. If 90 degrees is to my right and 270 is to my left, then a compass would put 0/360 at the top, and 180 at the bottom. But the navball has those two swapped.

If I launch from this view, and I press D, the nose of my rocket points to my right, and the level indicator moves right along the navball on the 90 degree line. Press A, nose points to left, level indicator moves left along 270. Both the motion of the nose and the navball match and make sense visually.

But pressing W, the nose of the rocket points away from me, which I know on a compass is 0/360/north. But on the navball, 0/360 is at the bottom, so the level indicator moves toward me (or more accurately, the ball rolls away from me), but the visual effect is that the rocket nose and navball are moving in opposite directions. Same for pressing S, just in the opposite directions.

I'm trying to wrap my head around this, and maybe a more direct question is, why is north and south on the navball opposite of a compass?

The problem it causes is when I'm trying to use only navball to hit a maneuver node. My north-south motions are always the opposite of what I intend, because I'm not used to the positions being swapped yet.

You might be thinking "wait a moment, north and south are flipped!". The reason is that you're effectively looking straight up at the sky, not down on the ground like with maps of Earth. You get the same effect on star maps, if you put north at the top east and west appear reversed, for the same reason.

Yes, in fact, I was replying to an earlier post that what's confusing is that north and south are flipped.

Now that you've mentioned the star map, I can see why this is. The difficulty comes in maneuvering from an external view, and trying to use the navball instead of watching rocket movement. For north-south movements, I keep expecting the ball to react the same as east-west, and I'll initially move in the wrong direction. I suppose this is just a matter of getting used to it.

Edited September 26, 2014 by tetryds

[Lunaran]

Picture the gimbal is inside out.

Stare at it like one of those qbert illusions where the cubes flip orientation, until you see a concave bowl instead of a convex ball.

Now imagine you're at the center of it, looking out.

[GoSlash27]

This is the exact same paradox that is presented by looking in a mirror.

The image in the mirror is reversed on the lateral plane (left/ right), but is *not* reversed in the vertical plane (up/down).

Your nav ball is inverted, and should be thought of as being viewed from the inside instead of outside.

Nothing else going on here beyond that.

Best,

-Slashy

[GroovyMike]

Thanks everyone for the quick responses and help. I really appreciate it. The star chart, concavity, and mirror analogies help a lot.

Part of the problem is I started out doing all my maneuvering by watching the ship, not the navball. Now I'm trying to navigate more by instrument, but I'm in the habit of looking at the ship still.

Just a matter of getting in a different frame of mind and practicing, I'm sure.

[Taki117]

Thanks everyone for the quick responses and help. I really appreciate it. The star chart, concavity, and mirror analogies help a lot.

Part of the problem is I started out doing all my maneuvering by watching the ship, not the navball. Now I'm trying to navigate more by instrument, but I'm in the habit of looking at the ship still.

Just a matter of getting in a different frame of mind and practicing, I'm sure.

If you are not adverse to Mods you could get Raster Prop Monitor and fly from inside the cockpit, this way your rocket movement and "joystick" movement will make more sense.

[Kryxal]

Should I point out that there's a BIT of difference between "adverse" and "averse"?

[Hannu]

Just a matter of getting in a different frame of mind and practicing, I'm sure.

If you fly mostly with rockets it is practical to change W and S -controls and I and K -controls. After that you can easily turn ship orientation or make RCS -translations to marks on navball. Unfortunately, if you use also planes, you have to change behavior back and forth or get used to "strange" controls.

[Simes]

It's like Kryxal says, when you're on the pad, you're looking straight up. When you're using a compass with a map, you're looking "down".

Try this with a map and compass if you like: look down at the map, with the map oriented in the usual way. Which way is north relative to where you're looking? Now, without moving any other way, look straight up. Which way is north relative to where you're looking now?

[RW-1]

The heading indicator is the wide V-shaped thing in the middle. That actually stays still, while the navball moves underneath it, like the artificial horizons on most aircraft.

When you start on the pad the compass directions on the navball are like this:

 S
W E
 N

(North is emphasised by a red line, by the way).

Let's hold on for a moment there.

When you start on the pad, WITHOUT having rotated your craft in the VAB beforehand, it is that way.

But let's put it like this, you have N, 90, 180, 270, and if you ahve flown airfraft then you know what they corespond to.

Your heading indicator at launch is straight up into the blue.

Don't think left right, etc. move to the heading you want.

I rotate my ships so that for an equatorial launch I don't have to "bank", but can just make a pitchover W, if I rotated the opposite way, it would be a pitchup.

It can take a bit orienting to the FDAI .... too bad we don't have nav needles in addition to the ball itself, you could enable AP and fly the needles

Edited September 26, 2014 by RW-1

[MarvinKitFox]

Fully explained, in two sentences:

In terrestrial maps, and when flying airplanes, your point-o-view is facing DOWN.

In KSP when launching rockets, your point-of-view is facing UP.

This has the effect of inverting north-south from the "usual" orientation.

[Pecan]

The navball doesn't have a 'rocket' and a 'plane' mode, it works in exactly the same way in both cases and the same as a real-life artifical horizon works too. Consider when you're flying a plane horizontally then pull back on the stick (S) - the plane's nose rises, pointing into the sky ... and so does the nose indicator on the navball. If you were flying North and pitch up to 90-degrees (without stalling ^^) the heading indicator follows the 0-degree (North) heading line. Similarly, pitching down from 90-degrees to horizontal again has to follow that line 'down' the sky.

[-Velocity-]

Funny. Even though I've been flying flight sims for nearly two decades now, I find the default keys of KSP confusing for a different reason- pitch is reversed. My brain views the "A", "S", "W", and "D" keys as ARROW keys. So, pressing "W" should make your nose go up, and pressing "S" should make your nose go down.

That the "A", "S", "W", and "D" keys should be treated as arrow keys and NOT as joystick axes is further underscored by the fact that the "A" and "D" keys apply yaw, not roll. If these keys were supposed to be regarded as joystick axes then shouldn't "A" and "D" be roll?

So anyway, what I always do is that I reverse the functions of "W" and "S" and "I" and "K" so that they are like arrow keys, which is the standard way to treat "ASWD" in video games anyway! Make "W"- up- make your nose go up, and "S"- down- make your nose go down.

An alternate setup- which wouldn't work for me but at least it would make sense- would be to make "A" and "D" be roll, and allow "W" and "S" to remain the same as they are in default. Then at least it could be logically argued that the the ASWD keys were something like joystick axes. The yaw axes would be switched to "Q" and "E".

And no, I do not get confused when I switch back to using a joystick. It's just that my brain doesn't regard a joystick as being anything at all like arrow keys on a keyboard- why in the hell should they be?! One is pressing four discrete buttons and the other is moving a single stick. But I've been told that a lot of people find pressing the up key to make your nose go down feels natural to them, which completely boggles my mind.

The default KSP key setup really reminds me of this-

Edited September 26, 2014 by |Velocity|