Why are FCs set up so you have to roll when you yaw? Can you configure yaw to be applied last?

I was teaching someone to fly in a simulator (FPV SkyDive) and they were very confused by the way you turn. I certainly remember finding it unnatural, but now I'm used to it: With the drone pitched forward slightly for normal flight, you would coordinate a yaw right and roll right to make a smooth turn.

Is there a reason it's not set up so that pitch/roll attitude are maintained as you yaw? So if you're pitched forward 30 degrees and the horizon is level, when you yaw those both stay the same? Are there moves that are easier using the existing standard? Or on the other hand, are there folks who have changed their setup (either FC settings or tx mixes) for different behavior?

Thanks for any insights!

5 comments

Are you talking about Acro mode?
In acro mode, or angle mode, you change the angle of the quadcopter. You don’t move in space, you change the angle the copter is moving through space.
I’d really like to show it in person - when you’re tilted forward 30° to fly forward, and then you roll, you roll around the already tilted axis, so you need to yaw to counteract a little bit. Also, the motion of turning tilts the drone forward, so you need to actually pitch backwards to combat that.
- Yes, Acro mode.
  Here's a visualization. In 3D modeling, you can apply transforms in different orders. So if you have a drone that's pitched 30 degrees forward (x rotation):
  If you want to yaw it around (z rotation) and you're using YZX rotation order you get the Acro mode behavior, where pure yaw spins the quad in the current plane of its arms:
  But if you're using XYZ rotation order, you end up turned around but still nose-down 30 degrees:
  
  It could be that I am a huge gaming nerd and picked up this hobby due to a Reddit comment, read by an AI voice from a YouTube video, but at the start I kind of treated it like FPS games, where you "pitch" up and down to look around. I flipped it to learn it the "correct" way, had to mentally adjust to instead of "looking up" I "pull back the lever to gain height"
  But having Yaw behave any different would be weird, not only considering how helicopters and planes work, but also how much harder some cinematic shots would be
I'm not sure what you're discussing - FPV quads should be able to yaw (when flat) without experiencing any rolling. If your flight controller isn't compensating for the rotation from the motor speed differential, that strikes me as a problem.
When you're moving forward at a 30 degree angle and you yaw, you'll roll a little bit as a result of the motion of the quad, but if you're level and stationary you should be able to yaw spin without any other rotations.
Maybe you could record a short clip from your flight sim and show us?
- Here's how it's working for me in FPV SkyDive. Moving forward at a 30 degree angle, and I want to curve around a pole. If I yaw + roll (both sticks to the side) I get a nice turn. If I just yaw (left stick only to the side) I end up looking at the sky.