one11 has it
. As you rightly say it is the AVA AF1. It certainly is an unusual aircraft. Aerodynamische Versuchsanstalt Göttingen (AVA), worked with the suction motor concept on two early experimental aircraft from 1938-40, the AF-1 and AF-2 to study boundary layer control. All flight tests were purely experimental and neither aircraft had a military equivalent. As the Fieseler Fi-156 Storch STOL aircraft fulled the utility role without need of a suction motor for ultra-short take-offs.
You have control.
Mel