Just been testing this "new" copter.
Easy to build
PnP no need for installing code
Can be finetuned via software, but has 3 knobs to adjust gain in field.
ESC: Got problem starting the BL motor, but when motor are running it's pretty powerfull. (Need slow startup)
Navigation mode: (hold position and RTH) need more testing. Not working very well.
Some drift: (maybe better prop or balancing motor/prop could help)
All in all: Nice little Y copter. The FY91Q can easily be intergrated in much bigger frame with bigger motor /ESC or be used in other configuration (like X frame).
Need for work with the RTH or Hold position function, too early for me to say it's rock solid.
Pilot: John Jensen, DK