Origins
Letov was founded in Prague in 1918, immediately after the establishment of the Czechoslovak Republic, making it one of the country's oldest aircraft manufacturers. Based at Letoňany airfield on the outskirts of Prague, the company — whose name derives from the Czech word for aviation — became one of the three principal pillars of the Czechoslovak aviation industry alongside Aero and Avia. Under chief designer Alois Šmíd, Letov produced a comprehensive range of reconnaissance aircraft, fighters, bombers, trainers, and airliners through the interwar period, with the Letov Š-328 reconnaissance biplane being its most produced and most important design. Like its contemporaries, Letov survived Nazi occupation and Communist nationalisation, continuing as a manufacturer and subcontractor through the Cold War era.
Aircraft Involved
Early Reconnaissance and Fighter Aircraft (1920–1926)
Letov's first designs were reconnaissance biplanes for the new Czechoslovak Air Force: the Letov Š-1 (1920, 28 built) and Letov Š-2 (1921, 64 built) established the company as a reliable supplier of military aircraft. The Letov Š-3 (1922) and Letov Š-4 (1922, 20 built) were monoplane and biplane fighters respectively. The Letov Š-6 (1923, 35 built) was a single-engine biplane bomber, with a civilian airliner variant as the Letov Š-19 (9 built). The Letov Š-10 (51 built) was a licence-built Hansa-Brandenburg B.I reconnaissance biplane. The Letov Š-16 (1926, 89 built) was a single-engine biplane bomber that became one of Letov's most important early production types, spawning numerous engine variants: the Š-116 (12 built), Š-516, Š-616 (12 built), Š-716, Š-816 (2 built), and Š-916. The Letov Š-18 (1925, 46 built) was a single-engine biplane trainer, developed as the Š-118 and the widely produced Š-218 (1926, 63 built) with steel-tube frame and improved engine.
Fighters and Sport Aircraft (1925–1935)
The Letov Š-20 (1925, ~118 built) was Letov's most produced fighter — a single-engine biplane that served as the standard Czechoslovak fighter of the late 1920s and was exported to several countries. The Letov Š-31 (1929, 33 built) was a further biplane fighter development, produced in engine variants Š-131 (racing, 3 built), Š-231 (35 built), Š-331, and Š-431. The Letov Š-39 (1931, 21 built) was a high-speed sport monoplane, developed as the Š-139 (6 built) and Š-239 (1935, 15 built) with various engines.
The Š-28 Family — Letov's Most Important Design
The Letov Š-28 (1929) was a single-engine reconnaissance biplane prototype that led to Letov's most significant production programme. The Letov Š-128 (1931, 12 built) and Letov Š-228 (4 built, for Estonia) were engine variants, and the Letov Š-428 a close ground support variant. The Letov Š-328 (1933, ~412 built) was the definitive production version — a single-engine biplane reconnaissance and light bomber aircraft that became the standard Czechoslovak Army co-operation aircraft of the 1930s, widely exported and still in service at the time of the German occupation in 1939. The Letov Š-528 (1935, 6 built) was a planned replacement. The Letov Š-32 (1931, 5 built) was a three-engine monoplane airliner, and the Letov Š-33 (1930) a single-engine monoplane bomber prototype.
Late Interwar Projects and Developments (1935–1938)
Through the late 1930s Letov developed numerous projects that were overtaken by the political crisis of 1938–39: twin-engine bomber studies Š-42, Š-43, Š-49, Š-52, and Š-56; fighter projects Š-44 and Š-51; and the Letov Š-50 (1938) twin-engine monoplane utility aircraft. The Letov Š-39 sport monoplane family continued in development through this period.
Postwar and Cold War Era
After liberation Letov produced the Letov L-290 Orel (1946) — a licence-built Junkers Ju 290 four-engine transport, one of the largest aircraft assembled in postwar Czechoslovakia. The Letov LF-107 Luňák (1948, 75 built) was a glider that became a popular postwar type. Various postwar projects were studied but not built: the L-52 jet fighter (based on the Me 262), L-103 pressurised airliner, L-105 ultralight, and L-501 fighter. In later decades Letov produced the Letov LK-2 Sluka (1988) and LK-3 Nova ultralight aircraft, and the MK-1 Kocour motor glider.
Legacy
Letov's legacy rests primarily on the Š-328 — a thoroughly competent and widely produced reconnaissance biplane that served the Czechoslovak Air Force faithfully through the 1930s. Less glamorous than Avia's B.534 or Aero's L-39, the Š-328 nonetheless represents the industrial backbone of Czech military aviation in the interwar period: reliable, producible, and exported across Central Europe. Letov's Letoňany factory site remains part of the Czech aerospace industry to this day.