The Zlin Z-37 Čmelák (Czech: "Bumblebee"), also known as LET Z-37 Čmelák is an agricultural aircraft which was manufactured in Czechoslovakia. It is powered by a Soviet-built Ivchenko reciprocating engine. The aircraft is used mainly as a cropduster.

Design work on the first purpose-designed agricultural aircraft started in Czechoslovakia in 1961, with a cooperation of two manufacturers: Let Kunovice and Moravan (Zlin brand). The first prototype, designated as XZ-37, first flew on 29 March 1963 (other sources:29 June). It was a cantilever low-wing monoplane of tubular metal construction, the wings and stabilizers covered with duralumin and the fuselage and control surfaces made of fabric. It had a fixed undercarriage with a fully castering tail wheel, but locked to the rudders for ground handling. The pilot's cockpit was in front, immediately behind a 315 hp radial engine, with a hopper for chemicals situated behind the cockpit. This offered the pilot a good view, but was potentially dangerous in case of an emergency landing. A mechanic could be seated behind the hopper, facing backwards. There were also spray booms mounted under the wings. There is also a freight version with open space instead of hopper and spray equipment and a -3 variant with three passenger seats facing rearwards.

The aircraft was produced from 1965 under the designation Z-37. From 1971, the Z-37A was produced, with a strengthened construction. It was produced until 1975, and then in 1983-1984. 677 were produced, including 27 two-seater Z-37A-2s for crew training.

On 6 September 1981 the prototype XZ-37T first flew, powered by a (691 shp) Walter M-601B turboprop engine. Two further prototypes of the definitive turboprop version, the Z-37T Agro Turbo, powered by a less powerful M-601Z engine, flew on 12 July and 29 December 1983. As well as the new engine, it had longer-span wings (13.63 m) fitted with winglets.

The Z-37T was produced from 1985 until 1994, with a total of 51 aircraft built, including some Z-37T-2 two-seater trainers. Later production aircraft were redesignated Zlin Z-137T.

SOURCE: Wikipedia