To Igor:
The cartoon caracter "Popey" on the I-16's rudder is the emblem of the 4a "Escuadrilla Moscas" (4th Moscas Squadron). Several I-16 (typ 5 and typ 10) of this squadron were flown by famous republican pilots like Saladriga, Morales or Zarauza.
I hope it will help you. :)

PS: I wish someone could make the translation!