This is the mounting for the pole i am using. it is a 1" x .035, give some flex and is light. used steel tube and plate for bushings and mountings. I have hard mounts in top and bottom of each spar end to mount to. started by trying to mount the gopro there by stickies but video was not good so moved to hard mounts, still no good, moved to pole, got some good and progressing from there. DO ALL THIS AT YOUR OWN RISK OR AS THEY SAY, DO NOT DO WHAT I DO. DO NOT DO THIS AT HOME.
