JN-4 JennyJN 4 Jenny airplane model. The JN 4 Jenny was generally used for primary flight training, but some were equipped with machine guns and bomb racks for advanced training. After World War I, hundreds were sold on the civilian market. The airplane soon became the mainstay of the "Barnstormer" of the 1920s, and some Jennies were still being flown in the 1930s. Scale: 1 32. Wingspan 16 5 8 inches, Length 10 3 4 inches.