The PZL SM-4 Łątka (Polish: Dragonfly) was a prototype three-seat

helicopter A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes ...

of the 1960s, developed by WSK PZL-Świdnik in Poland. Of largely conventional design and construction, a single prototype was built, but was not flown as a result of engine problems.

Design and development

In 1960, a design team led by Jerzy Kotliński at the Polish WSK PZL-Świdnik factory began work on a new short-range light helicopter, which was given the designation SM-4 Łątka.Taylor 1966, p. 116."Projekty Śmigłowców WSK-Świdnik"
. ''Polska Technika Lotnicza: Materiały Historyczne''. 16 October 2005. WSK PZL-Świdnik had previously license-built Soviet

Mil Mi-1 The Mil Mi-1 (USAF/DoD reporting name "Type 32", NATO reporting name "Hare") was a Soviet three- or four-seat light utility helicopter. It was the first Soviet helicopter to enter serial production. It is powered by one Ivchenko AI-26V radial ...

helicopters, designated SM-1, starting in 1955. They had also designed and built the PZL SM-2 derivative of the Mi-1; the SM-4 was the first completely original aircraft design to be developed by them. The Łątka was designed as a three-seat, single-engined helicopter of conventional layout. It was equipped with a single three-bladed

glass-fibre Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cloth ...

main rotor and a two-bladed tail rotor, with power provided by a Narkiewicz WN-6S air-cooled

flat-six A flat-six engine, also known as a horizontally opposed-six, is a six-cylinder piston engine with three cylinders on each side of a central crankshaft. The most common type of flat-six engine is the boxer-six engine, where each pair of opposed cy ...

horizontally-opposed A flat engine is a Internal combustion engine#Reciprocating engines, piston engine where the cylinders are located on either side of a central crankshaft. Flat engines are also known as horizontally opposed engines, however this is distinct fro ...

piston engine, which was mounted behind the cabin. The pilot and two passengers were accommodated in an enclosed cabin with extensive glazing. The tail rotor was carried on the end of an open tail boom constructed of welded steel tube, giving a layout similar to that of a

Bell 47 The Bell 47 is a single-rotor single-engine light helicopter manufactured by Bell Helicopter. It was based on the third Bell 30 prototype, which was the company's first helicopter designed by Arthur M. Young. The 47 became the first he ...

. The undercarriage consisted of two skids. A single prototype of the SM-4 was completed; the helicopter was used to carry out ground tests, but it never flew as the WN-06S engine failed to receive clearance for flight operations, and the program was abandoned."PZL-Swidnik History - Helicopter Design"
''Globalsecurity.org''. Retrieved 6 June 2012.

Specifications (performance estimated)

References

;Citations ;Bibliography * Taylor, John W. R. ''Jane's All The World's Aircraft 1966–67''. London: Sampson Low, Marston & Company, 1966.

External links

Photograph of the SM-4
{{DEFAULTSORT:PZL SM-4 Latka PZL aircraft 1960s Polish helicopters Abandoned civil aircraft projects Single-engined piston helicopters

Design and development

Specifications (performance estimated)

See also

References

Further reading

External links