Avia BH-4
 The Avia BH-4 was a prototype fighter aircraft built in Czechoslovakia in 1922. It was a development of the BH-3 fitted with a Hispano-Suiza 8 engine in an attempt to improve the aircraft's performance. To accommodate the new powerplant the forward fuselage was considerably redesigned and the structure in general and undercarriage in particular were strengthened. Performance was found to be only marginally better than the BH-3 and development was quickly abandoned.