The Antonov A-9 was a single-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 the

USSR The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

in the 1940s, a development of the record setting Red Front 7.

Design and development

Oleg Antonov had designed sailplanes since the early 1930s, most memorably the Red Front 7 which, flown by Olga Klepikova, set a world distance record of that stood from 1939 to 1951. The A-9 is seen as a development of that aircraft, though detailed information from this period of

Soviet The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

aviation is often limited. The

fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...

s and tail units of the two aircraft were very similar but the wings were quite different. The A-9 was a

cantilever A cantilever is a rigid structural element that extends horizontally and is unsupported at one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cantilev ...

, shoulder wing monoplane. In plan, the wing had a short, constant chord centre section and long, straight tapered outer panels, with a sweep on both edges, terminating in rounded and downward-curled wingtips. The panels were demountable from the centre section for transport; unusually, the centre section was an integral part of the fuselage structure, its single box spar spanning the section unbroken. The spar continued beyond the central section-outer panel joint, the whole wing having

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 ...

covering ahead of the spar and

aircraft fabric covering Aircraft fabric covering is a term used for both the material used and the process of covering aircraft open structures. It is also used for reinforcing closed plywood structures. The de Havilland Mosquito is an example of this technique, as are ...

aft. Long span, tapered, fabric covered and mass balanced

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 ...

occupied about two-thirds of the

trailing edge The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge meets.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 521. Aviation Supplies & Academics, 1997. ...

s of the outer panels; these panels also carried

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 ...

-type airbrakes, placed just behind the spar and ending at the panel mounting joint. The wing section was slightly reflexed towards the rear and thick, with maximum depth far forward at only about 20% chord, making the profile steep-nosed. The ply-covered fuselage of the A-9 was oval in cross-section, deep ahead of the wings and almost circular to the rear, giving it a pod-and-boom appearance. The fixed tail surfaces were also ply-covered, the

fin A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. F ...

narrow but with a small fuselage

fillet Fillet may refer to: *Annulet (architecture), part of a column capital, also called a fillet *Fillet (aircraft), a fairing smoothing the airflow at a joint between two components *Fillet (clothing), a headband *Fillet (heraldry), diminutive of the ...

. The control surfaces were fabric covered. In plan the horizontal tail was tapered with sweep on both edges; the broad, curved and

balanced rudder Balanced rudders are used by both ships and aircraft. Both may indicate a portion of the rudder surface ahead of the hinge, placed to lower the control loads needed to turn the rudder. For aircraft the method can also be applied to elevator (air ...

reached to the keel and was hinged well aft, almost in line with the

elevator An elevator (American English) or lift (Commonwealth English) is a machine that vertically transports people or freight between levels. They are typically powered by electric motors that drive traction cables and counterweight systems suc ...

trailing edge, for clearance and moment. The upper fuselage line was almost flat, even over the rear part of the long, two piece

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 ...

, though its windscreen curved down sharply into the nose. There was no skid or wheeled

undercarriage Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include: *The landing gear of an aircraft. *The ch ...

; instead the A-9 was launched from a wheeled, drop-off dolly and landed on the locally internally strengthened fuselage underside, aided by a tail bumper. Overall, the structure of the A-9 was heavy and so the

wing loading In aerodynamics, wing loading is the total weight of an aircraft or flying animal divided by the area of its wing. The stalling speed, takeoff speed and landing speed of an aircraft are partly determined by its wing loading. The faster an airc ...

was high at 30.5 kg/m² (6.2 lb/ft²), compared, for example, with the Slingsby T.25 Gull 4, a contemporary glider with a wing loading of 22.3 kg/m² (4.6 lb/ft²). Higher wing loadings provide higher speeds and better glide angles between thermals but poor climbing in weak lift. The Red Front 7 is known to have used

water ballast Ballast is weight placed low in ships to lower their centre of gravity, which increases stability (more technically, to provide a righting moment to resist any heeling moment on the hull). Insufficiently ballasted boats tend to tip or heel exce ...

on its record flight but the A-9 was not thus equipped.

Operational history

Because of their speed, the A-9s concentrated mostly on competition flying and record setting.

Variants

''Data from'' Sailplanes 1945–1965 ; span: Standard version. ; extended span: Weight increased by 10 kg (22 lb) but useful load 100 kg (220 lb) as standard, wing area decreased to , wing loading 34.5 kg/m² (7.0 lb/ft²). This version ''may'' have been named the Antonov A-10, though other sources associate this designation with a two-seat variant of the A-9.

Specifications

References

{{Antonov aircraft A-09 1940s Soviet sailplanes Glider aircraft Aircraft first flown in 1948