The Ikarus Košava () is a two-seat

sailplane A glider or sailplane is a type of glider aircraft used in the leisure activity and sport of gliding (also called soaring). This unpowered aircraft can use naturally occurring currents of rising air in the atmosphere to gain altitude. Sailplan ...

designed and built in

Yugoslavia , common_name = Yugoslavia , life_span = 1918–19921941–1945: World War II in Yugoslavia#Axis invasion and dismemberment of Yugoslavia, Axis occupation , p1 = Kingdom of SerbiaSerbia , flag_p ...

in the early 1950s. It won the 1954

World Gliding Championships The World Gliding Championships (WGC) is a gliding competitions, gliding competition held roughly every two years by the FAI Gliding Commission. The dates are not always exactly two years apart, often because the contests are always held in the sum ...

in the two seat category and came second in the same event two years later.

Design and development

The Košava was commissioned by the Yugoslavian Aeronautical Union and built at the Ikarus factory to replace the pre-

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

Kranich II aircraft. It is a wooden glider, covered in a mixture of

plywood Plywood is a composite material manufactured from thin layers, or "plies", of wood veneer that have been stacked and glued together. It is an engineered wood from the family of manufactured boards, which include plywood, medium-density fibreboa ...

and

fabric Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, and different types of fabric. At first, the word "textiles" only referred to woven fabrics. However, weaving is no ...

. The wings are built up around single spars, with ply covering to the leading edge forming a D- or torsion box. Behind the spar the covering is fabric. Forward sweep of 4.5° at one quarter chord allows the centre of gravity to be far enough forward to place the rear of the two

tandem Tandem, or in tandem, is an arrangement in which two or more animals, machines, or people are lined up one behind another, all facing in the same direction. ''Tandem'' can also be used more generally to refer to any group of persons or objects w ...

seats at it and the leading edge. The wing is of

gull wing The gull wing, also known as Polish wing or Puławski wing, is an aircraft wing configuration with a prominent bend in the wing inner section towards the wing root. Its name is derived from the seabirds which it resembles and from the Polish a ...

design, the roots at the

shoulder wing A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple wings. A monoplane has inherently the highest efficiency and lowest drag of any wing config ...

position and with 7° of dihedral on the inboard 40% of span. A subsidiary spar carries plain flaps inboard, mass balanced and sealed

ailerons An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement around ...

, divided into two sections, outboard. The first prototype had a pair of under surface airbrakes on each wing but these were replaced on the second aircraft with

Schempp-Hirth Schempp-Hirth Flugzeugbau GmbH is a glider manufacturer based in Kirchheim unter Teck, Germany. History Martin Schempp founded his own company in Göppingen in 1935, with the assistance of Wolf Hirth. The company was initially called "Sport ...

parallel ruler Parallel rulers are a Technical drawing, drafting instrument used by navigators to draw parallel lines on charts. The tool consists of two straight edges joined by two arms which allow them to move closer or further away while always remaining pa ...

action brakes. The flaps on the Košava could be set to downward or upward deflections. For slow fight they were lowered through either 15° or 30°. The ailerons automatically drooped when this was done: 15° of flap drooped the inner ailerons 10° and the outer ones 5°, 30° of flap produced 15° and 10° of droop. The wing section without flaps was a high camber one best suited for high lift at low speed but raising the flaps through either 6° or 9° lowered the camber. 6° increased the speed and 9° made the glider autostable in pitch, particularly valuable for blind flying in cloud. The semi-monocoque fuselage is ply covered and oval in cross section, becoming finer and more circular towards the tail. the fixed rear surfaces were also ply covered, carrying fabric covered control surfaces. The horizontal tail has almost constant chord and is forward of the

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, airship, or other vehicle that moves through a fluid medium (usually air or water). On an airplane, the rudder is used primarily to counter adverse yaw ...

, which is broad and extends down to the keel. The fuselage deepens forward, with a fixed skid for landing, aided by a tail bumper The Košava was launched on a drop-off wheeled dolly. The tandem cockpit has a long, low, level topped multi piece blown

canopy Canopy may refer to: Plants * Canopy (biology), aboveground portion of plant community or crop (including forests) * Canopy (grape), aboveground portion of grapes Religion and ceremonies * Baldachin or canopy of state, typically placed over an a ...

which extends aft to about mid-chord where it is faired into the fuselage. The Kosawa first flew in March 1953.

Operational history

Very soon after its first flight the Košava, flown by Božidar Komac, was engaging in competitions. After winning the Yugoslavian National Championship, it achieved third place at the first German gliding competition allowed after

, held at

Oerlinghausen Oerlinghausen (; ) is a city in the Lippe district of North Rhine-Westphalia, Germany located between Bielefeld and Detmold in the Teutoburg Forest. At the end of February 2023, it had 17,314 inhabitants.UK for the World Gliding Championships (WGC) at Camphill; flown by Božidar Komac and Zvonimir Rain, it won the two seater competition by a large margin. Two years later, piloted by Rain, it was placed second in the same category at the WGC at

Saint-Yan Saint-Yan is a commune in the Saône-et-Loire department in the region of Bourgogne-Franche-Comté in eastern France. Geography The Arconce forms part of the commune's southern border and the Loire part of its western border. Climate Educa ...

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

. It also set a world women's speed record over a closed course, and a Yugoslavian national distance record. It won the two seat Yugoslav national championships in 1955. Despite its success in competition, only the two prototypes of the Košava were built.

Variants

;Košava: Standard long span, gull wing version. ;Košava II: Wing straightened and reduced in span to . ;Košava 57:Košava variant produced in 1957 ;Košava 60:Košava variant produced in 1960

Aircraft on display

*Košava ''YU-5022'', the first prototype: Museum of Aviation,

Belgrade Belgrade is the Capital city, capital and List of cities in Serbia, largest city of Serbia. It is located at the confluence of the Sava and Danube rivers and at the crossroads of the Pannonian Basin, Pannonian Plain and the Balkan Peninsula. T ...

Specifications (Košava)

Notes

References

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External links

Göttingen 549 airfoil
{{DEFAULTSORT:Ikarus Kosava Kosava 1950s Yugoslav sailplanes Shoulder-wing aircraft Gull-wing aircraft Aircraft first flown in 1953