|First flight||29 June 1963|
|Primary user||Czechoslovak civilian aviation|
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 and development
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 tailwheel, 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 main user of Z-37s was Czechoslovakia (now Czech and Slovak Republics) along with East Germany and other Eastern Bloc countries. Many were exported to the Sudan and India and flown there almost non-stop with the hopper used as extra fuel tank. Variants are as far a field as England and the USA. Current use is limited because of fuel costs and are now used mainly in Slovakia. Many are used for glider towing, having the ability to easily tow two gliders and often transport four gliders in tow for cross country.
A record has been set by a Z 137T in Slovakia, towing nine gliders.
- First prototype.
- First production version built between 1965 and 1971.
- Second production version with strengthened construction. Built between 1971 and 1975 and later between 1983 and 1984, 650 built.
- Two-seat version for crew training, 27 built.
- Pilot plus three passenger version. Conversion of "A" version. Rear-facing seats.
- Prototype of the turboprop version powered by Walter M-601B engine, built in 1981.
- Z-37T Agro Turbo
- Turboprop version with bigger span wings, powered by Walter M-601Z engine and built between 1985 and 1987. 28 built including Z-37T-2 trainer.
- Two-seat turboprop version for crew training built between 1985 and 1987.
- Further development version.
Aircraft on display
- New Zealand
Specifications (Z 37A)
Data from Jane's All the World's Aircraft 1976-77 
- Crew: one, pilot
- Capacity: 1, mechanic (optional), 650 l of chemicals
- Length: 8.55 m (28 ft 0½ in)
- Wingspan: 12.22 m (40 ft 1¼ in)
- Height: 2.90 m (9 ft 6 in)
- Wing area: 23.80 m² (256.2 ft²)
- Empty weight: 1,043 kg (2,295 lb)
- Useful load: 600 kg ()
- Loaded weight: 1,850 kg ()
- Max. takeoff weight: 1,850 kg (4,080 lb)
- Powerplant: 1 × Avia M462RF air-cooled 9-cylinder radial engine (supercharged), 235 kW (315 hp)
- Never exceed speed: 270 km/h (145 knots, 167 mph)
- Maximum speed: 210 km/h (113 knots, 130 mph)
- Cruise speed: 183 km/h (99 knots, 114 mph)
- Stall speed: 81 km/h (45 knots, 51 mph)
- Range: 640 km (345 NM, 398 mi)
- Service ceiling: 4,000 m (13,125 ft)
- Rate of climb: 4.7 m/s (925 ft/min)
- Take-off run: (no load) less than 50 m (170 ft) - loaded from 125 metres (410ft) in still air
- Landing run: less than 100 metres in still air
- Fuel Capacity: 250 litres
- Fuel Grade: Not less than 73 Octane (Unleaded 95 usually used)
- Fuel Consumption: 52 litres per hour cruise, 110 litres per hour full power
Aircraft of comparable role, configuration and era
- Industry Observer, Aviation Week & Space Technology, September 23, 1963, v. 79, no. 13, p. 23.
- J.W.R Taylor 1976, p.30.
- J.W.R Taylor 1988, p.52.
- "History of production of ZLIN aircraft". Zlin Aircraft. Archived from the original on October 24, 2007. Retrieved 2008-11-03.
- M. Taylor 1996, p.389.
- "AIRCRAFTS COLLECTION [sic]". Aviation Museum. Aviation Museum. Retrieved 9 July 2018.
- "Muzej Yugoslovenskog Ratnog Vazduhoplovstva". AviationMuseum.eu. Retrieved 9 July 2018.
- "Zlin Agri-Plane". Ashburton Aviation Museum. The Ashburton Aviation Museum. Retrieved 9 July 2018.
- J.W.R. Taylor 1976, pp.30—31.
- Taylor, J.W.R (editor) (1976). Jane's All the World's Aircraft 1976-77. London: Macdonald and Jane's. ISBN 0-354-00538-3.
- Taylor, JWR (Editor) (1988). Jane's All the World's Aircraft, 1988-1989. Coulsden, Surrey, UK: Jane's Information Group. ISBN 0-7106-0867-5.
- Taylor, Michael (editor) (1996). Brassey's World Aircraft & Systems Directory 1999/97 Edition. London: Brassey's. ISBN 1-85753-198-1.
- Hans-Joachim Mau: Tschechoslowakische Flugzeuge, Transpress, Berlin 1987, ISBN 3-344-00121-3
- Photo and description[permanent dead link] (in Slovak)
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