What airfoils are used for VTOL ultralights at 60-70 deg AOA without flaps or slats?
An example of this would be the Blackfly with a takeoff distance of 3', about 25% of it's own length....!!!!
I understand most airfoils stall at about 15deg, slats and flaps allowing up to 30 deg AOA such as with the Zenith 701.
Yet the Blackfly has no slats or flaps and has controlled flight even at at 60,70,80,90 deg AOA.
I assume the distributed propulsion reduces the LOCAL AOA significantly, so that lift is only via the props from say 40-90 deg AOA, and then wings start to generate lift at about 40 deg AOA even without slats or flaps.
Yet, I was told distributed propulsion only works for low AOA. Very confused....
What airfoil type is used for this?
Would an airfoil like the Selig 1233 or Eppler 399 be appropriate for this? I understand these are low Re airfoils, but these usually stall at a lower AOA than a classic airfoil like the NACA65018 used in the Zenith701.
Or do you need something very fat that will stall at a much higher AOA, like an airfoil with 25%-30% thickness?