The Pentagon's Defense Advanced Research Projects Agency (DARPA) and Frontier Systems this year plan to flight-test a revolutionary unmanned helicopter that can remain airborne for up to 48h and achieve an unrefuelled range of 5,550km (3,000nm).
Neither DARPA nor Abraham Karem, Frontier president, will disclose details of the research effort, but it is known that the A160 Hummingbird is being developed initially as a vertical take-off and landing unmanned air vehicle. The A160 has a hingeless, rigid rotor as well as low disk-loading and low rotor tip speeds, which increase endurance dramatically.
Frontier is 16 months into a 30-month DARPA-funded technology demonstration. Work has concentrated on ground tests and flight-control development. DARPA says: "The basic goal is to develop an optimum-performance helicopter across a wide envelope of rotational speeds and to achieve a significant increase in hover and cruise altitudes."
Source: Flight International
