Powered by a pulsejet engine, it was the Netherlands' first drone to be successfully developed, and saw limited use in the late 1950s and early 1960s.
Developed in 1955,[1] the AT-21 was of conventional aircraft design,[2] with a high-mounted, constant-chord monoplane wing and a twin tail empennage.
Power was provided by a SNECMA AS-11 Ecrevisse pulsejet, mounted in a fairing underneath the aircraft's fuselage; the construction of the airframe made extensive use of plastic 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.
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.
[5] Data from Ordway and Wakeford,[3] Jane's All the World's Aircraft 1958-59[6]General characteristics Performance