[Yo-Yo]

Indeed. I once got into a discussion with someone who challenged by assertion that I could build a plane with NO airfoil at all, just a plank with an angle of attack of about 55 and it would fly.

He laughed at my ignorance of things aeronautical - until I took one of my RC models and fitted it out with a totally flat wing; a slab of balsa, it was, and flew it in front of him.

As a fellow R/C pilot, I need to remind you the Reynolds numbers that our models fly at compared to the Reynolds numbers of full scale aircraft.

Scale-wise, the air is much thicker to our models, and many such tricks as 3D hovering on the prop are easy at our scale, but has rarely been done full scale. (The Pogo being one full scale example.)

That being said, you could have just asked your friend if he's ever witnessed a full-scale aerobatic plane fly inverted. Or knife edge.

[John Valentine]

Indeed, good points.