I know they not as popular now and quads fly beta but still fly mine now and then since upgrading my quads to f4 v6 from old 8bit boards can’t believe the difference love betaflight 
Anyway i have spare set of motors and esc’s and was thinking of doing a mini tri with perhaps f4 v6 board as already got 2 on my quads pondering on where to wire servo and if i should use 3 escs as the 4 in 1 is so easy to connect. Any thoughts be interested to hear…
Hey, I’ve got an old 15" tricopter running ardupilot (gonna upgrade to inav) but it is something different that feels incredibly fluid, not something for robotic flips or anything like that but they are good cruisers and plenty of fun especially if you are looking for something different.
For attaching the servo you need to run it to a signal connection on the FC which one depends on the layout but if you have a 4in1 attached it may pull current but not sure I’m running separate escs.
Remember most servos take 5v so don’t do it to vbat unless you pick that type of servo.
Thx for speedy reply they do look a bit different eh i fly mainly los so sure i will continue to upgrade the tricopters have separate escs so will prob try them first. Just gotta decide on flight controller. Good shout with the 5v servo bet a lot of servos blown connecting straight to vbat eh! 
thx