The Aero A.30 was a biplane light bomber and reconnaissance aircraft built in Czechoslovakia in the late 1920s. It originated as an attempt by Aero to improve the performance of the Aero A.11, but soon evolved into quite a different aircraft, larger and more powerful than its predecessor. The aircraft is readily distinguished from other related types by the difference in spans between its wings – the upper set being of much greater span than the lower.
The Avia BH-21, first flown in 1925, was a robust biplane that served an important role in securing Czechoslovak national security during the period between World War I and World War II. As well as being a competent fighter, it was also an accomplished racer, winning several air races in 1925.
The Letov Š-18 was a Czechoslovak single-engined, two-seat biplane trainer. It was designed by Alois Smolík at Letov Kbely. The Š-18 first flew in 1925.
The Avia BH-1 was a two-seat sports plane built in Czechoslovakia in 1920. It was the first product of the Avia company, and it was originally designated BH-1 exp. The BH-1 was a low-wing braced monoplane of wooden construction, with tailskid undercarriage. Power was provided by a Daimler engine, which proved inadequate to fly the aircraft with both seats occupied.
The Avia BH-5 was a two-seat sport aircraft built in Czechoslovakia in 1923. It was based on the firm's experience with the BH-1 and shared that aircraft's basic design: a low-wing, braced monoplane. It received the nickname "Boska" due to its registration, L-BOSA, an appellation that was later transferred to the various Avia aircraft derived from this design. The BH-5 was flown competitively by Zdeněk Lhota at the Belgian Touring Aircraft Contest in Brussels in 1923, and won both the overall prize for the event and the King of Belgium Prize. The same year, it won the first prize in its class in the Czechoslovak President of the Republic Competition.
The Avia BH-9 was a single-seat sports plane built in Czechoslovakia in 1923, based on the BH-5. As with other developments in the BH-1 lineage, the BH-9 was a low-wing braced monoplane that accommodated the pilot and passenger in tandem, open cockpits. The BH-9's structure was strengthened to allow the use of a higher-power engine than in its predecessors, and for the first time, this was a domestically-produced powerplant.
The Avia BH-10 was a single-seat aerobatic sports plane built in Czechoslovakia in 1924, based on the Avia BH-9, which was in turn developed from the BH-5 and BH-1. It was easily visually distinguished from the BH-9 by the tall anti-roll pylon added behind the open cockpit in order to protect the pilot in the event that the aircraft flipped over or crashed while inverted. At least 20 examples were bought by the Czechoslovakian Army as a training aircraft and operated under the designation B.10.
The Avia BH-12 was a two-seat sport aircraft built in Czechoslovakia in 1924, the final development of the Avia BH-9 family that had its roots in Avia's first aircraft design, the BH-1. It was a low-wing, braced monoplane intended for sports flying, and featured a redesigned wing that could be folded to allow the aircraft to be towed by road. The wing pivoted around its spar and then folded back, flat against the fuselage sides.
The Avia BH-25 was a biplane airliner built in Czechoslovakia in 1926.
The Avia BH-26 was a two-seat armed reconnaissance aircraft built in Czechoslovakia in 1927. It was a single-bay unstaggered biplane with equal-span wings and a fixed tailskid undercarriage. Both upper and lower wings featured long-span ailerons, which were dynamically balanced by a small auxiliary airfoil mounted to the upper surface of the lower ailerons. Its design was typical of this type of aircraft built during World War I and the years following; pilot and observer sat in tandem open cockpits with the observer armed with a machine gun on a ring mount. As with many other Avia designs, the BH-26 originally had no fixed fin, only a rudder, but this was changed in service.
The Avia BH-28 was a military reconnaissance biplane aircraft developed in Czechoslovakia in 1927 to meet a requirement for such an aircraft by the government of Romania. Avia based the design on their BH-26, but replaced the engine with an Armstrong Siddeley Jaguar, as specified in the requirement. The completed aircraft was taken to Bucharest for demonstration, but no order ensued, and this prototype was the only example constructed.
The Avia BH-29 was probably a trainer aircraft maybe built in Czechoslovakia in 1927, in the improbable hope of marketing it to both the Czechoslovakian Army, and probably to Czechoslovakian Airlines as a primary trainer. It was an unconventional design, an unequal-span biplane of wooden construction and with tailskid undercarriage. The pilot and instructor sat in tandem open cockpits. A more powerful version was built, powered by a 120 hp (89 kW) Walter NZ-120 radial engine.
The Breda A.4 was a biplane trainer produced in Italy in the mid-1920s. It was of conventional configuration with a two-bay unstaggered wing cellule and seating for the pilot and instructor in tandem open cockpits. Apart from civil use, the A.4 was also adopted by the Regia Aeronautica as a trainer. At least some examples were produced in floatplane configuration as the A.4idro.
The Zlin Z-526 Akrobat is a Czech sports plane used in aerobatics.
The Zlín Z-XII was a Czechoslovak two-seat sports aircraft, and the first major design success by the Zlínská Letecká Akciová Společnost (Zlín) aircraft manufacturing company, after its founding in Otrokovice after the takeover by the Bata Group.
The Focke-Wulf A 20 Habicht was an airliner developed in Germany in the late 1920s. It was a high-wing cantilever monoplane with fixed tailskid undercarriage. The fuselage was deep and seated four passengers in a fully enclosed cabin. The type was not bought by the airlines and only a few examples were built.
The Focke-Wulf S 2 was a trainer aircraft built in Germany in the late 1920s. It was a conventional parasol-wing monoplane with fixed tailskid undercarriage. The pilot and instructor sat side by side in an open cockpit. Only a single example was built.
The Fokker S.IV was a military trainer aircraft produced in the Netherlands in the mid-1920s. It was a conventional, single-bay biplane with staggered wings of unequal span braced with N-struts, essentially a radial-engined development of the S.III. The pilot and instructor sat in tandem, open cockpits and the undercarriage was of fixed, tailskid type with a cross-axle between the main units. The Royal Netherlands Army Aviation Group purchased 30 examples and used them right up to the German invasion of the Netherlands in 1940. On 14 May that year, a few surviving S.IVs escaped to France alongside some S.IX trainers, but never flew again.
The Hopfner HS-5/28 was a utility aircraft built in Austria in the late 1920s. It was a conventional, parasol-wing monoplane with seating for two occupants in tandem, open cockpits. The landing gear was of fixed, tailskid type with divided main units. Two examples were built with Walter NZ60 engines, followed by two more with the more powerful NZ85 for Swiss aeroclub use. One of these latter machines remained in service until 1934.
The Morane-Saulnier MS.138 was a military trainer aircraft produced in France in the late 1920s,
