The only change in approach is you start to benefit from doing an additional tuning step after autotune and adding some D term.
great, that is what i hoped to hear. whats the typical amount of tilt?
There isn’t one but I would recommend between 3 and 5 degrees.
I am not making any recommendations on that. They are all engineering decisions to be made by the designer, in context.
From your previous answer it looks there are no adverse effects so i guess it would be nice to have a better yaw at the expenses of a negligible efficiency drop.
what if the tilt of each motor are slightly different (due to adjustment imprecision)?
yeah if you have an otherwise normal build motor tilt seems like a no-brainer.
Can someone help me understand the difference between a “radial tilt” and a “circumferential tilt”? Maybe a little diagram or link?
From reading this post it seems a radial tilt is discouraged and a hack for crappy flight controllers. But circumferential is completely valid for increasing yaw authority. Am I understanding correctly?
yes you understand correctly
Thanks. I can’t see clearly in the videos above, I’m still a bit confused what the physical difference between a radial and circumferential tilt is. Do you have a picture you could post that helps explain this?
oh sorry. @dkemxr’s paper shows circumferential tilt. radial tilt would be towards the center of the drone.
@dkemxr Very interesting paper thank you!! It seems tilting it by 3° is a win/win condition. Don’t see any adverse effects.
Yes, that would seem to be the sweet spot. It’s a small angle to control for but I suppose if you have a good way of mounting the motors so they are at equal angle it’s beneficial.
Test mule 
Hey @lordvon
I came across this post and I think it’s interesting. I would like to try it on my quad.
I’m unsure what you mean by “tilting motors in the direction of torque” Does it matter if I tilt the rotors inward (toward the orange line) or outward (away from the orange line)?
The sketch below is what I mean by inward tilt
@vicson that would be the wrong way. the tilt has to result in a torque that is in the same direction as the power torque; e.g. opposite the rotor spin.
for this x-quad, you want the front props blowing towards the front, and the back props toward the back.
I realize I never followed up on this thread. Tilting 6 degrees has worked wonderfully for my x-quad. Unfortunately I dont have any hard numbers but efficiency difference is negligible and yaw authority is noticeably stronger. I will incorporate at least 3-6 deg of tilt in all my builds.
Got it. Thanks for the info. I will give it a try! I’m thinking about starting at 3 deg first and increasing from there
