What light night fighter did Avia build in the 1920s?

The Avia BH-23 was a night fighter prototype built in Czechoslovakia in 1926. Its design was based on the day fighter BH-21 and incorporated the structural changes introduced in the BH-22 trainer, which is why it was originally designated BH-22N. For the night role it was fitted with searchlights and other night flying equipment.

The origins of the BH-21 go back to the Avia BH-17, a conventional biplane that Pavel Beneš and Miroslav Hajn designed in the early 1920s in response to a requirement from the Czechoslovak Defence Department for a new fighter. The BH-22, for its part, was a trainer built in Czechoslovakia in 1925 and based on the BH-21 fighter. It used a smaller engine and had its armament removed. The lighter engine forced a reduction in wing stagger. The fuselage structure received no significant modifications, and the weight reduction further increased the ultimate load factor. Some BH-22 examples carried a gun camera.

The Czechoslovak Air Force showed no interest in the BH-23 project, and no sale was closed. The BH-21, from which it derived, took part in no recorded combat throughout its entire service life.