I-16 Type 24

[manintrees]

From Wikipedia:

A 1939 government study found that I-16 had exhausted its performance potential. Addition of armor, radio, battery, and flaps during the aircraft's evolution exacerbated the rear weight distribution to the point where the aircraft required considerable forward pressure on the stick to maintain level flight and at the same time developed a tendency to enter uncontrolled dives. Extension and retraction of the landing flaps caused a dramatic change in the aircraft attitude. Accurate gunfire was difficult.