Antonov An-4 / An2ZA
The An-2ZA variant of the An-2 (design bureau designation An-4) is intended specially for high-altitude meteorological research. The An-4 has a glazed position immediately in front of the tail fin for an observer. The ZA suffix standing for Zondirovanie Atmosfery, translatable as 'air sampling'.
The An-4 is able to maintain power up to 10,000m by the ASh-62IR engine has a TK supercharger mounted on the starboard side of the cowling. The spinner of the An-2 standard model is deleted to aid engine cooling, and the original ailerons have been replaced by an unslotted variety.