On October 20, 1947, test pilot OKB-115 F.L.Abramov took off on a new light-engine aircraft designed for use as a liaison and sanitary in the Air Force, as well as passenger - for local airlines of the GVF. He received the designation Yak-12 (product 21A). While maintaining the overall design solutions, a number of improvements were made on the aircraft to improve take-off and landing characteristics and meet the requirements of potential customers. The wing span and area were slightly reduced, a fixed slat was installed along its entire leading edge, to reduce the aerodynamic drag of the aircraft, instead of a strut, a profiled tie-rod was introduced into the design of the pyramidal landing gear, connecting the wheel axis with the attachment point of the cord rubber shock absorption. The weight of the empty aircraft and the take-off practically remained unchanged, These and other improvements made it possible to almost halve the take-off of the aircraft during take-off. The maximum speed of the Yak-12 decreased by 37 km / h, and the prak.