Avia BH-21

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The Avia BH-21

The Avia BH-21, first built in 1925, was a robust bi-plane that served an important role in securing Czechoslovakian national security during the interwar years, as well as being a competent fighter, it was also an accomplished racer, winning several air races of its time.

[edit] History

A conventional bi-plane, the predecessor of the BH-21, the BH-17, was designed by Pavel Benes and Miroslav Hajn in 1922 as a response to a Czech Defense Department requirement for a new fighter aircraft. The BH-17 was actually only part of 5 Avia designs submitted to the Defense Department along with competing designs from the Letov and Aero firms. After extensive review the BH-17, one of Avia's three biplane designs, was chosen and limited production initiated for evaluative purposes. Testing revealed some deficiencies in the BH-17 and a subsequent re-design in 1924 morphed the BH-17 into its final form as the BH-21 which included straightened interplane bracing and a better field of view for the pilot. A special training version, designated the BH-22, was also created. Both versions utilized 180 Hp Hispano-Suiza 8fb engines built under license by Skoda Works. The BH-21 was put into production in 1925 and had a 1 year production run which yielded 170 aircraft with 126 being produced by Avia for the Czech Air Force while another 50 were produced under license by the Belgian company, Société Anonyme Belge de Constructions Aéronautiques "SABCA" for the Belgian Air Force. While in service the BH-21 saw no combat as it was retired before the outbreak of World War II. In spite of this it served as an important stepping stone to the more advanced BH-33 and BH-53 types. The BH-21's most lasting achievement came when a racing version, the BH-21R, won several national air-race competitions in 1925 sporting an uprated HS 8Fb engine producing over 400 hp.