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 operation ...

developed in the Netherlands by Aviolanda. Powered by a

pulsejet file:Pulse Jet Engine.PNG, 300px, Diagram of a valved pulsejet. 1 - Air enters through valve and is mixed with fuel. 2 - The mixture is ignited, expands, closes the valve and exits through the tailpipe, creating thrust.3 - Low pressure in the engi ...

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

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 wings. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...

wing and a twin tail

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 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 ...

; the construction of the airframe made extensive use of

plastic Plastics are a wide range of synthetic polymers, synthetic or Semisynthesis, semisynthetic materials composed primarily of Polymer, polymers. Their defining characteristic, Plasticity (physics), plasticity, allows them to be Injection moulding ...

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 specific ...

-type

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

s from a zero-length launch 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 A parachute is a device designed to slow an object's descent through an atmosphere by creating Drag (physics), drag or aerodynamic Lift (force), lift. It is primarily used to safely support people exiting aircraft at height, but also serves va ...

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 bolts 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 Strategy, strategic purpose that is conducted using reconnaissance aircraft. The role of reconnaissance can fulfil a variety of requirements including Artillery observer, artillery spott ...

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

Specifications

References

Citations

Bibliography