Boeing A160 Hummingbird
The Boeing A160 Hummingbird is a testbed for a vertical take-off and landing unmanned aerial vehicle. The Hummingbird was developed by Boeing in cooperation with the U.S. Agency for military research projects ( Abbreviation for: DARPA ) developed as a long -range reconnaissance helicopter. On 14 and 15 May 2008, the Hummingbird set a new world record for helicopters with a non-stop flight duration of 18 hours and 42 minutes.
Development
The development of Hummingbirds originally started at Karem Aircraft in March 1998. Karem Aircraft already developed the GNAT 750, which formed the basis for subsequent RQ -1 Predator. This gave a 30- month contract from DARPA, which provided the construction of an unmanned helicopter light for tactical reconnaissance. The newly developed for autonomous control elements were built R22 Helicopter in a Robinson and tested up to an accident in 2000 in 215 flight hours.
A160
The first Hummingbird prototype, called the A160 and equipped with a three -blade rotor, began with the first floating experiments on 7 December 2001 before it made its first flight on 29 January 2002.
The first test flights showed that the original three-blade design was not powerful enough to meet the DARPA - performance requirements. Therefore, it rose to a four - leaf version of the A160 to a Subaru four- cylinder engine, which first flew in November 2002. After a total of three A160 with four-blade rotor in the test flight operations were, there was obtained a further contract for 75 mil. U.S. dollar. This called for the construction of four additional machines, which should be equipped with a KW600 diesel engine. Therefore the fuel consumption should be reduced and thus the flight duration is increased. But after the first and third prototype had crashed, none of the four machines was completed with diesel engine.
After the failure of the four Hummingbirds with diesel engines, the entire A160 program was initially before the crash and Karem Aircraft ran into financial difficulties. Boeing then took over the program in May 2004 and incorporated Karem Aircraft in the Boeing Phantom Works a.
A160T
Boeing began the construction of the Hummingbirds to radically revise and built between 2005 and 2007 a total of five more prototypes, which are now referred to as A160T. It changed the rotor design and replaced the Subaru four- cylinder engine with a 6- cylinder petrol engine with 290 kW piston. At Boeing A160T, the U.S. Army and the U.S. Navy now showed interest. The pattern A160T was named YUL -18 Warrior for military use. In flight program until 2008 Boeing increased successively the flight duration and varied installed reconnaissance systems. The United States Special Operations Command ( SOCOM ) expressed an interest in first 12 machines and increased early 2009, the need for 20 MQ - 18th For the series variant, the production start was scheduled for 2009, Boeing plans to use the gas turbine Pratt & Whitney Canada PW207D with 410 kW of power, as well as the external Waffenmitführung of up to eight Hellfire missiles.
On 28 July 2010, there was again an accident with a Hummingbird. In a autorotation landing near the California airport Victorville ( Victorville Southern California Logistics Airport ) the aircraft crashed on the side. In a 45-day continuous test series in the jungles of Belize on 10 September 2010 plunged a further prototype of the helicopter at the airfield Central Farm in San Ignacio in the Cayo District from.
Construction
In order to meet the high performance requirements, particularly in the area of flight time, the Hummingbird has a very unusual for helicopter aerodynamic design. The hull is made extremely thin and made entirely of composite materials. To achieve the required stealth properties of the body is coated with a radar absorbent material and the landing gear is retractable. The rotor is designed rigid and has a hingeless rotor head. For noise reduction, the maximum rotor speed is limited so that the outer ends do not break the sound barrier. Boeing states that it has halved in this way the noise about. That the Hummingbird despite the limitation rotor reaches high flight performance is partly due to the lightweight construction of the composites, on the other hand the fact that the rotor blades are relatively large in relation to the hull.
The series machines, the DARPA Forester radar system is used.