The Aviolanda AT-21 was a

target drone A target drone is an unmanned aerial vehicle, generally remote controlled, usually used in the training of anti-aircraft crews. One of the earliest drones was the British DH.82 Queen Bee, a variant of the Tiger Moth trainer aircraft operational ...

developed in the Netherlands by Aviolanda. Powered by a

pulsejet 300px, Diagram of a pulsejet A pulsejet engine (or pulse jet) is a type of jet engine in which combustion occurs in pulses. A pulsejet engine can be made with few or no moving parts, and is capable of running statically (i.e. it does not need ...

engine, it was the Netherlands' first drone to be successfully developed, and saw limited use in the late 1950s and early 1960s.

Design and development

Developed in 1955, the AT-21 was of conventional aircraft design, with a high-mounted, constant-

chord Chord may refer to: * Chord (music), an aggregate of musical pitches sounded simultaneously ** Guitar chord a chord played on a guitar, which has a particular tuning * Chord (geometry), a line segment joining two points on a curve * Chord ( ...

monoplane 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 planes. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...

wing and a

twin tail A twin tail is a specific type of vertical stabilizer arrangement found on the empennage of some aircraft. Two vertical stabilizers—often smaller on their own than a single conventional tail would be—are mounted at the outside of the aircra ...

empennage The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third ed ...

. Power was provided by a SNECMA AS-11 Ecrevisse pulsejet, mounted in a fairing underneath the aircraft's

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...

; the construction of the airframe made extensive use of

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...

in the nose and tail, with the center-section being of metal construction, and the wings and tail were made of foam-filled plastic with metal stabilizers and rudders. Launch was by

JATO JATO (acronym for jet-assisted take-off) is a type of assisted take-off for helping overloaded aircraft into the air by providing additional thrust in the form of small rockets. The term ''JATO'' is used interchangeably with the (more specifi ...

-type

booster rocket A booster rocket (or engine) is either the first stage of a multistage launch vehicle, or else a shorter-burning rocket used in parallel with longer-burning sustainer rockets to augment the space vehicle's takeoff thrust and payload capabilit ...

s from a

zero-length launch The zero-length launch system or zero-length take-off system (ZLL, ZLTO, ZEL, ZELL) was a method whereby jet fighters and attack aircraft could be near-vertically launched using rocket motors to rapidly gain speed and altitude. Such rocket boos ...

ramp; a trolley for conventional takeoff from a runway was also available. Control was by radio commands from a remote guidance station, set up like an aircraft cockpit; if radio contact was lost, the parachute recovery system would automatically deploy. The parachutes could also be manually released at the end of a mission; the wing and tail would be separated by

explosive bolt A pyrotechnic fastener (also called an explosive bolt, or pyro, within context) is a fastener, usually a nut or bolt, that incorporates a pyrotechnic charge that can be initiated remotely. One or more explosive charges embedded within the bolt a ...

s upon landing to simplify recovery and reduce the risk of damage during the process. Endurance was up to one hour, and it was possible to fit a payload of cameras for

aerial reconnaissance Aerial reconnaissance is reconnaissance for a military or strategic purpose that is conducted using reconnaissance aircraft. The role of reconnaissance can fulfil a variety of requirements including artillery spotting, the collection of image ...

duties.Ordway and Wakeford 1960, p. N1.

Operational history

The first flight of the AT-21 took place in late 1955. The first Dutch drone to successfully complete development, it entered service with the

Royal Dutch Navy The Royal Netherlands Navy ( nl, Koninklijke Marine, links=no) is the naval force of the Kingdom of the Netherlands. During the 17th century, the navy of the Dutch Republic (1581–1795) was one of the most powerful naval forces in the world an ...

. Production of the AT-21 continued through 1958.El-Sayed 2017, p.102.

Specifications

References

Citations

Bibliography