There are many threads in this forum about jerky videos during yaw turns of a Mini2, and I have contributed to a number of them. One possible contributing factor floated for these jerks is the relatively low yaw moment of inertia for this tiny drone, coupled with the rather coarse virtual stick frame rate sending commands to the drone during flights. To test this theory, I added outrigger weights to the Mini2 that raised its yaw inertia from a measured 8,130 gm-cm^2 up to 19,613 gm-cm^2, a factor of 2.4 or so. With very limited testing, I can see no difference between videos of yaw sweeps using DJI Fly and those using Litchi, each being “butterly smooth” as we like to say.
The outrigger was made from two soda straws with 5/16" bolts on the ends, connected to the drone with coffee stirrers at the drone center of mass. The combined weight of the bolts was only 19 grams, so the drone flew well. I measured the yaw inertias of the two configurations using a Bifiliar Tortional Pendulum, a fancy term for a pendulum with two strings supporting the drone. The inertia is calculated as I = MgT^2b^2/(16Pi^2*L), where M is the support mass, g is the acceleration due to gravity, T is the period of torsional oscillation, b is the distance between the strings, and L is the pendulum length. Here’s a picture of the rig with the upside-down drone at the bottom:
If I can figure out how to post a video of the rig in action, I will do so. Lots more testing to do, but promising early results.