I have been building a variable pitch tricopter and wanted to share my results so far.
Basically - I chose a tri and not a quad, because the tri geometry is the same as a traditional heli 120 deg swash plate. Since I can't write a firmware on my own, I wanted to use an off the self solution.
I used a home made simple frame
3 e-flite park 370 hollow shaft motors with their variable pitch props
3 castle ESCs that I had laying around.
Here is a picture of the motor and blades on rear arm
Here is a list of my various attempts
1 - radio programed as 120 deg swash and used airplane stabilizer - worked but not great
2 - used a commercial heli flybarless system - it flew , but could not set gains low enough
3- used my ardupilot mega - with traditional heli firmware - worked, but could not remove oscillations
4- I retried the APM with heli firmware and reduced the swash upper and lower limits to 1400 to 1550 and lowered rate p to 0.8 and stabilize p to 3.5 no I term and stabilize D of 0,07
This allowed me to fly and hover, but very touchy
Check out the video - and now I need suggestions .
I think one point is I need to redesign the pitch servo so that I use more of the servo throw, but mechanically reduce the movement - I have lost alot of resolution using such a narrow pitch range in mission planner
Here is a video of the tri on a table
Sorry the above video was cut off - here is the full video