Hello guys, today I've been to Schwarzheide again in order to do some black things there. We applied some soot-oil-paint to our Twin Astir's wing to visualize laminar separation bubble as well as turbulent reattachment. We attached the winch cable, pushed the plane back as far as possible, than applied the paint and took off immediately leaving the paint no time to run down. After the winch had taken us to an altitude of a bit more than 400m, we smoothly descended back to the runway enjoying a beautiful view of the autumn landscape. After touchdown, a number of insects took possession of the blackened surface the heated in the sun. I guess they didn't get very happy with that. Well it did not wok as well as in the wind tunnel and the reattachment line doesn't shoe the curvature I had supposed due to the displacement of the fuselage, which just means that the differences are mainly because of blockage effects in the open test section of our tunnel. hope you like WIL Grob G-103 Twin Astir (D-5954) soot-oil-kerosene Panasonic DMC FZ-50 Canon HF-100 Corel Photopaint 7