It was based on the BH-21J which demonstrated promising results by combining the original BH-21 airframe with a licence-built Bristol Jupiter radial engine.

The performance of the latter example was finally acceptable for the Czechoslovakian defence ministry to order a small production run of only five aircraft.

[1] Development continued with an almost total redesign of the fuselage, replacing the wooden, slab-sided structure with one of oval cross-section, built up from welded steel tubes.

Nevertheless, the response from the Czechoslovakian military was lukewarm (although two were bought for the national aerobatics team), and Avia again looked abroad for customers, this time selling 20 aircraft to the Kingdom of Yugoslavia, along with a licence to produce another 24.

This version finally brought the company the domestic sales that it had been hoping for, with 80 aircraft ordered by the Czechoslovak Air Force.