i'm at my wit's end on this one.
as you'll see on the videeo, about 60% of the time the heli flies fine. but, seemingly at random it develops a terrible shudder.
new, solid (home made) main shaft, new blades, new feathering shaft, went through all the servos and they're very smooth on the bench and under load (spooled up in my hand).
power to board is directly off the lipo rather than through the brushless esc (caused pulsing motor issue).
went through every screw on the heli and all is tight. anyone have any ideas why it would just start shuddering, then clear itself back up on its own?
pay particular attention at 1:18 for a closeup example of the shudder. they are throughout the whole video...1:04, 1:08, 1:14 are the best closeups. the video didn't come out as well as i'd hoped. in person it is very easy to see throughout the whole flight.
Watch at YouTube
if it ain't broke, break it.