04 Apr '15, 8am

Grob G520T Egrett

A total of five airplanes were built, the single-seater Proof-of-Concept aircraft, three production single seaters and one two-seater trainer. After an evaluation period, the two Air Forces decided that the aircraft did not fit their requirements. Since then, some of the single seaters have been successfully used as ad-hoc high-altitude research platforms (for example by Aurora Corporation in the USA and by the Weltrauminstitut in Berlin).

Full article: http://fas.org/man/dod-101/sys/ac/row/egrett.htm