In several cases the code name of BH-39 after her designers Benes and Hajn is used for this type.
The prototype (designated BH.39NZ) first flew in 1931 with a 120 hp Walter NZ nine-cylinder radial engine. The 1936 next 8 built used 140 hp Walter Gemma radials (designated BH.39G). After this the 160 hp Armstrong Siddeley Genet Major was fitted (designated BH.39AG of 1937).
Praga E-39.21, the 21st production one, was powered by a Walter Gamma engine.
A total of 149 aircraft appears to have been built with 125 used by the Luftwaffe as primary trainers during WW2. No mention of cross bracing while later models had ‘N’ shape interplane struts, cross-braced layout, while the rest on the paint guides had ‘N’ shaped struts.
BH.39NZ
Two seat primary trainer
Engine: 120 hp Walter NZ
BH.39G
Engine: 150 hp Walter Gemma
BH.39AG
Engine: 150 hp Armstrong Siddeley Genet Major 1A
BH.39RS
Span: 10.00m
Length: 7.00m
Height: 2.57m
All Aero 