The Heinkel He 50 was a dive-bomber used by the German Luftwaffe in the 1930's, By WWII, it was obsolete, though still used in secondary roles, for example as a night ground-attack plane. Some were exported to China and fought against the Japanese, whose navy air force used the very similar Aichi D1.
This item consists of 4 models on a sprue. I have simplified the elaborate strutwork of the original. No pilots are included. Shapeways' Reduced Aircraft Factory offer pilot figures that can be added.