The war destroyed the whole Polish aviation industry. As soon as the Eastern part of Poland was liberated by the Red Army in October 1944 a group of designers gathered in Lublin, under the direction of Tadeusz Sołtyk, thus creating the first Polish post-war construction team. They designed a touring low-plane aircraft of a wooden construction called Szpak-1, with a M-11F radial engine. The plane was not built, nevertheless it gave the beginning to a Szpak family. In early 1945 the construction team moved to Łódź and on April 1, 1945, created Lotnicze Warsztaty Doświadczalne. On October 28, 1945, the prototype of the Szpak-2 was flown for the first time; first Polish post-war civilian plane in operation. It broke its landing gear during a landing, but was repaired. The official first flight took place on 10 November 1945. Szpak was a strutted monoplane low-wing utility/touring plane of wooden construction, powered by a radial engine Bramo Sh 14, left in the country by the retreating Germans. A crew of 4 sat in a closed cab under a multi-part canopy, in two rows. Szpak-2 was not built in series, the single aircraft was used by the factory, then in 1947-1948 by the Polish government as a utility and light transport aircraft. Being the first plane registered in Poland after the war it carried the registration SP-AAA. It completed some 500 flights and transported some 250 passengers in total and was retired on April 5, 1948. The Szpak-2 had a conventional fixed landing gear. On 17 December 1946, for the first time flew its improved experimental variant called Szpak-3 with a fixed tricycle landing gear. It was not built in a series either, and the prototype was used as a courier plane by the Ministry of Foreign Affairs during 1947, then by the factory. It was retired on March 6, 1950. The next variant, the Szpak-4A, was designed as an aerobatic aircraft. Only one prototype was built, flown on May 20, 1947. It had a steel fuselage frame rather than a wooden one, and a two-men side-by-side open cab. It was not certified as an aerobatic aircraft however, and was used by the factory as a utility plane in 1947–1948. The only variant produced in a series was the 4-seater utility plane called Szpak-4T, utilizing the steel fuselage frame with a conventional landing gear. Contrary to Szpak-2 and 3, its fuselage was lowered behind a canopy. It was ordered by the Ministry of Communication and ten planes were built in 1947-1948 by the PZL in Mielec as the first Polish post-war planes built in a series. The very first one was flown on January 5, 1948. The planes had markings: SP-AAF to SP-AAO, and SP-AAR. They were used by the Polish civilian aviation - regional aero clubs until 1952, except for the SP-AAG, which was retired in 1955. They are also known as WSK Szpak-4T.
