http://i614.photobucket.com/albums/t...psb36fb5b8.jpg
We?ve seen the yarn tufts on RVs with a level flight upright stall (positive angle of attack (AOA)), where the disruptive airflow moves from the fuselage towards the wing tips. I wanted to see if the same thing happened for the bottom of the wing in inverted flight or negative AOA. My attempts for video recording level flight inverted stalls or accelerated stalls in steep inverted turns was not very apparent since my RV doesn?t have a good break inverted, but more or less mushes even with the stick max forward. To exaggerate a negative AOA, I went vertical and then pushed hard, which disrupted the lower wing airflow. The video also showed the yarn being sucked in the gap between the aileron and wing with positive AOA, but went flat when the AOA approached zero as shown in the hammerhead. All of the yarn tufts break loose at the same time for the inverted spin.
http://www.youtube.com/watch?v=gS0uH...3pJbKyyySNj9Pg
http://www.youtube.com/watch?v=OCmSX...3pJbKyyySNj9Pg inverted spin .
Bill McLean
RV-4 slider
Lower Alabama
yarn tufts bottom of wing air flow
Linear Mode
