MQ-18 A160 Hummingbird Warrior

On 04 May 2004 Boeing announced it had acquired Frontier Systems Inc., developer of the A-160 Hummingbird and Maverick unmanned aerial vehicles (UAV). Frontier's platforms and technologies add to Boeing's portfolio and capabilities in unmanned systems that include the Joint Unmanned Combat Air System X-45, ScanEagle and other concepts under development. Frontier also sells the Maverick UAV, a retrofitted commercially available helicopter, to the U.S. Special Operations Command. The Maverick UAV has also been used as a test bed for A-160 technologies.

The A-160 Hummingbird, a vertical take-off-and-landing UAV, has been designed to fly up to 2,500 plus nautical miles with 30 to 40 hour endurance. Its modular payload design can carry up to 1,000 pounds. The A-160 offers range and endurance unprecedented in the history of helicopter UAV design. It will provide reconnaissance, surveillance, target acquisition, communication relay, precision re-supply, sensor delivery and eventually precision attack capabilities.

The A160 Hummingbird, built by DARPA and Frontier Aviation of San Diego, will exploit a hingeless, rigid rotor concept operating at the optimum rotational speed to produce a vertical take-off and landing (VTOL) unmanned air vehicle (UAV) with very low disk loading and rotor tip speeds resulting in an efficient low power loiter and high endurance system. This unique concept offers the potential for significant increases in VTOL UAV range (more than 2,000 nm) and endurance (24-48 hours). Detailed design, fabrication and testing of this vehicle is being conducted to establish its performance, reliability, and maintainability. The A160 concept is being evaluated for surveillance and targeting, communications and data relay, lethal and non-lethal weapons delivery, assured crew recovery, resupply of forces in the field, and special operations missions in support of Army, Navy, Marine Corps, and other Agency needs. It is being developed as a component of the DARPA/Army Future Combat Systems (FCS) Program. In addition, this program will evaluate application of the optimum speed rotor concept to other systems including heavy lift and tilt rotor capabilities. The program will also develop highly efficient heavy fuel engine technologies to further advance current range and endurance projections as well as improve operational reliability and logistics compatibility.

The Army's Advanced Rotary Wing Vehicle (RWV) Technology project matures and demonstrates rotary wing unmanned and manned platform technologies for the Objective Force. It is envisioned that the Objective Force will need unmanned and manned rotorcraft systems that have significantly increased/improved lift, range and survivability with an overall reduction in logistics. Key to this effort is the demonstration of a vertical takeoff and landing (VTOL) UAVs for the Objective Force. The critical technologies to support these capabilities will be matured through Technology Demonstrations (TDs) of prototype UAVs, rotors, active controls, structures, drive train, and threat protection. The near term demonstration of unmanned, VTOL UAVs will focus on the A-160 Hummingbird UAV and the Organic Air Vehicle (OAV), to include the Micro Air Vehicle variant, for Reconnaissance, Surveillance and Target Acquisition (RSTA) capability. These demonstrations will focus on military operations and the application of military specification on these maturing systems.

The A-160 Hummingbird is a DARPA project to produce an unmanned helicopter that can fly 2,500 nautical miles over 40 hours and carry 300 pounds of air-to-ground missiles. The Army wants to take over the project in 2003 (years ahead of schedule) in order to ensure that the aircraft ends up being what the Army wants it to be. A production decision would be made around 2006. The A-160 has a 300hp internal combustion engine and a three-bladed rotor. The Army plans to add a tactical common data link in order to receive the aircraft's data and direct its flight and weapons.

The A160 helicopter demonstrator, about the size of the Predator-A, was built by Abraham Karem and his team at Frontier Systems of Irvine, California, under contract to DARPA. The A160's predicted top speed is 140 knots." The Hummingbird is 35 feet long with a 36-foot rotor diameter. The A160 prototype made its first forward flight on 29 January 2002.

The A160 will have range, endurance, and altitude capabilities unprecedented in the history of helicopter design. The A160 has a conventional main-tail-rotor helicopter configuration, but the conventional appearance is misleading. A contemporary helicopter features lightweight flexible rotors that are connected to the rotor hub through articulated joints. Such rotors are designed to provide smooth flight operation with little vibration and good control authority.

However, they can only do so within a limited range of speeds, normally at as high an RPM as possible before the wingtips break the sound barrier. The helicopter's rotor RPM is roughly constant while the aircraft is in flight. This is inefficient, particularly when the helicopter is flying below maximum speed or with an optimal load.

The A160's carbon-fiber composite rotor blades are tapered, and their cross-section varies from root to tip. They are light but stiff to avoid vibration, and their stiffness also varies from root to tip. The rotor system is rigid and hingeless, and features a larger diameter and lower disk loading than that of a conventional helicopter with the same lift capacity.

The A160 rotor can be operated from 140 to 350 RPM. Coupled with a fuel-efficient piston engine results in a helicopter that not only has unbelievable fuel efficiency, but good speed, unprecedented altitude capability, and is very silent.

The A160 project began in early 1998, with Frontier Systems modifying a light commercial Robinson R22 helicopter to a UAV configuration to test flight-control systems. The R22 was lost in an accident in early 2000, but not before it had flown for 215 hours under autonomous control. The innovative A160 rotor system is now being ground tested.

The A160 demonstrator will weigh about 1,800 kilograms (4,000 pounds), and will have rotor blades 5.2 meters (17 feet) long. The demonstrator will be powered by a commercial piston engine with over 300 horsepower, and will have a payload capacity of more than 135 kilograms (300 pounds). Possible payloads include EO/IR imaging and SAR sensors. Apparently there is work being done on integrating SAR receiving antennas into the rotors themselves, though the transmit antenna will be mounted on the fuselage.

The demonstrator, which was given the name "Hummingbird", will have a top speed of 260 KPH (160 MPH), 24 to 36 hours endurance, 5,500 kilometer (3,450 mile) range, and a flight ceiling of 9,150 meters (30,000 feet). A production version could have an endurance of up to 48 hours and a ceiling of 16,800 feet (55,000 feet). First flight was in early 2002.

The A160 is a technology development exercise and is not being designed for a specific operational mission, but its general design concept envisions a UAV that could deploy itself from the US to a combat area, or perform deep penetrations into hostile territory. The US Army and the US Special Operations Command (SOC) are interested in the project, with the SOC considering uses such as extracting troops trapped behind enemy lines.

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