The Avia BH-33 was a single-seat biplane fighter developed in Czechoslovakia in 1927 by designers Pavel Beneš and Miroslav Hajn.
It was based on the earlier BH-21J, which had shown promise when fitted with a licence-built Bristol Jupiter radial engine.
The BH-33 was the first Avia fighter to feature a fixed tail fin, marking a design shift from previous rudder-only configurations.
Prototypes and Early Development
BH-33 (First Prototype)
Flew on 21 October 1927, but performance was only marginally better than the BH-21.
BH-33-1
Two improved prototypes followed, powered by Jupiter VI and Jupiter VII engines.
The latter met performance expectations, leading to a small production run of five aircraft.
Exports
Three aircraft were sold to Belgium, which considered licence production but did not proceed.
Structural Redesign
BH-33E
The BH-33E introduced a welded steel tube fuselage with an oval cross-section, replacing the earlier wooden slab-sided structure.
Though considered world-class for its time, the Czechoslovak military showed limited interest.
Two BH-33Es were used by the national aerobatics team.
Exports
Yugoslavia purchased 20 aircraft and licensed the production of 24 more.
The Soviet Union evaluated 2–3 aircraft but did not adopt them.
BH-33E-SHS (Yugoslav Production)
Built under licence by Ikarus, powered by the IAM K9 radial engine.
22 units were produced and served in the Royal Yugoslav Air Force until WWII.
BH-33L Domestic Success
Introduced in late 1929, featuring longer-span wings and a Škoda L W-block engine.
This variant finally secured domestic orders, with 80 aircraft delivered to the Czechoslovak Air Force.
Served as standard equipment into the early WWII period.
BH-33H / BH-133
A single experimental aircraft built in 1930, powered by a BMW-built Pratt & Whitney Hornet engine.
Redesignated BH-133, but did not enter production.
P.W.S.A (Polish Licence Variant)
Poland acquired one BH-33 and a licence to build 50 aircraft between 1929 and 1932.
Designated PWS-A, these served in the Polish Air Force until the late 1930s.
World War II Operational History
By the outbreak of WWII, the BH-33 was largely obsolete
Czechoslovakia
Retired before 1939; replaced by the Avia B-534.
Poland
PWS-A variants were withdrawn before the German invasion.
Yugoslavia
The BH-33E-SHS aircraft saw limited combat during the April 1941 Axis invasion, quickly being outclassed by modern Luftwaffe fighters.
Croatia
Used surviving BH-33s for training and liaison roles under Axis alignment.
Legacy
The Avia BH-33 was a milestone in interwar aviation, showcasing Czechoslovak engineering and securing modest export success.
Though eclipsed by faster monoplanes by WWII, it remains a symbol of early fighter innovation, with preserved examples commemorating its role in aviation history.
