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49-857: The development of Hummingbird was begun for DARPA by Frontier Aircraft in 1998. From 2003 both the US Army and the US Navy also shared in funding the project. In May 2004, the company was acquired by Boeing and became integrated into Boeing Phantom Works and then into the Advanced Systems group of Boeing Integrated Defense Systems . Early A160s were powered by modified Subaru automotive engines, but newer versions use Pratt & Whitney PW207D turboshaft engines. The A160 continued with developmental flight tests in 2010, but test flights had already demonstrated greater endurance, higher altitudes, more extensive autonomy, and greater payload. The program had ambitious goals of

98-480: A two-speed transmission to optimize efficiency at different speeds and altitudes, a technique called "optimum speed rotor technology", invented by Abe Karem. It is primarily because of these features that the Hummingbird can fly with less power - and thus use less fuel - than comparable conventional helicopters, which only adjust blade pitch and keep the rotor at constant rpm. In August 2005, Frontier Systems, by then

147-421: A "safety pilot" (a human pilot riding on board and capable of recovering the aircraft in the event of a failure of the unmanned flight control system). Since much of the software and avionics systems were shared between Maverick and A160, Maverick remained in service long after A160 began flight operations. After acquiring Frontier Systems in 2004, Boeing halted most development of Maverick but it continued flying as

196-645: A $ 29.9 million contract to Boeing for two A160Ts and control systems. Kaman received a similar contract worth $ 46M. NAVAIR issued a stop-work order on the A160 in December 2011, before a Quick Reaction Assessment. The K-MAX was eventually chosen over the A160T for the unmanned resupply role by the Marines, and was sent to Afghanistan in 2011. On July 28, 2010 an A160T crashed at Southern California Logistics Airport . It autorotated to

245-476: A 2,500-mile (4,000 km) range, 24-hour endurance, and 30,000 ft (9,100 m) altitude. Flights were largely autonomous, with the aircraft making its own decisions about how to fly itself so as to meet certain objectives, rather than relying on real-time human control. The A160 achieved maximum speeds of over 140 knots (260 km/h), though endurance and altitude were its goals, not speed. The aircraft measures 35 ft (11 m) from nose to tail and has

294-514: A 4-cylinder Subaru engine. On September 20, 2004, the Hummingbird made its first flight since Boeing took over the program the previous May. The test program operated from the Southern California Logistics Airport near Victorville, California . In August 2005, the Hummingbird was flown around Victorville in a 1,200-mile course at 60 knots and 4000 feet, one of the longest helicopter flights ever. A mechanical failure caused

343-796: A Boeing subsidiary, received a $ 50 million contract from the Naval Air Warfare Center Aircraft Division "to assess the military utility and affordability of a long-range VTOL UAV employing a wide variety of adaptable payloads". In October 2007, DARPA awarded Boeing a $ 6.3 million contract to deliver an A160T aircraft and modified pod for the Autonomous Real-time Ground Ubiquitous Surveillance-Imaging System (ARGUS-IS) program. In 2008, DARPA considered stub wings carrying weapons. The Hummingbird made its first flight in January 2002, using

392-532: A compound helicopter through the 1960s, culminating in the 16H-1A Pathfinder II which flew successfully in 1965. Thrust was obtained via a ducted fan at the tail. The Bell 533 of 1969 was a compound jet helicopter. 275 knots (316 mph; 509 km/h). The compound helicopter has continued to be studied and flown experimentally. In 2010 the Sikorsky X2 flew with coaxial rotors . 250 knots (290 mph; 460 km/h). 0.8. 360 to 446. No wings. In 2013

441-461: A conventional wing to offload the rotor during high-speed flight, allowing it to rotate at slower speeds. The 1932 Pitcairn PCA-2 autogyro had a maximum speed of 20-102 knots (117 mph; 189 km/h), μ of 0.7, and L/D of 4.8 NACA engineer John Wheatley examined the effect of varying advance ratios up to about 0.7 in a wind tunnel in 1933 and published a landmark study in 1934. Although lift could be predicted with some accuracy, by 1939

490-419: A few percent. This introduces limitations in areas of the flight envelope where the optimal speed differs. In particular, it limits the maximum forward speed of the aircraft. Two main issues restrict the speed of rotorcraft: These (and other) problems limit the practical speed of a conventional helicopter to around 160–200 knots (300–370 km/h). At the extreme, the theoretical top speed for

539-416: A fixed rpm with varying radius. Conventional helicopters have constant-speed rotors and adjust lift by varying the blade angle of attack or collective pitch . The rotors are optimised for high-lift or high-speed flight modes and in less demanding situations are not as efficient. The profile drag of a rotor corresponds to the cube of its rotational speed . Reducing the rotational speed and increasing

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588-474: A quiet engine, which until then sounded like "a lawnmower in the sky". The new development was renamed the " Predator ". The Hummingbird was developed by Frontier Aircraft. In May 2004, the company was acquired by Boeing and integrated into Boeing Phantom Works and then into the Advanced Systems group of Boeing Integrated Defense Systems . In early 2008, Karem Aircraft teamed with Lockheed Martin in offering Karem's Optimum Speed Tilt-Rotor (OSTR) design for

637-399: A rotary winged aircraft is about 225 knots (259 mph; 417 km/h), just above the current official speed record for a conventional helicopter held by a Westland Lynx , which flew at 400 km/h (250 mph) in 1986 where its blade tips were nearly Mach  1. For rotorcraft, advance ratio (or Mu, symbol μ {\displaystyle \mu } ) is defined as

686-449: A rotor diameter of 36 ft (11 m). The project was abandoned by the US Army in December 2012. During the initial development of the A160 airframe and rotor system in 1999 to 2000, Frontier Systems simultaneously designed the Maverick vertical take-off and landing (VTOL) UAV as a testbed for avionics, software and flight control systems. The Maverick was a highly modified version of

735-444: A single 90 ft diameter main rotor supplemented by a 46 ft wide wing with forward thrust provided by twin turboprop engines. In forward flight the power to the rotor was reduced to about 10%. Its maximum speed was 166 knots (191 mph; 307 km/h) a record set in 1959. 0.6. Rotor speed was 120 (high speed cruising flight as an autogyro) to 140 ( flare out while landing as a helicopter) rpm During forward flight 60% of

784-488: A six-cylinder piston engine. Frontier Systems was awarded a contract for four more A160s in October 2003. A total of three vehicles were produced by Frontier Systems. Vehicles 1 and 3 were lost in crashes. Frontier began a planned KW600 Diesel engine for the vehicle, but never completed it. A Diesel engine would have nearly doubled the vehicle endurance due to lower fuel consumption. Frontier Aircraft, and later Boeing, carried out

833-517: A thrust turbojet to offload the rotor were first added to an XH-51A and in 1965 this allowed the craft to achieve a world speed record of 272 miles per hour (438 km/h). The Cheyenne flew just two years later, obtaining its forward thrust from a pusher propeller. Although pre-production prototypes were ordered the program met problems and was cancelled. 212 knots (244 mph; 393 km/h). 0.8. .. \ 20%. The Piasecki 16H Pathfinder project similarly evolved an initially conventional design into

882-585: A training asset and for reducing risk in technology development for the A160. Four Mavericks were flown by the US Navy, carrying Wescam Electro-Optical/Infrared sensor system, possibly among other sensors. Since being acquired by the military, most Maverick operations are unpublicized. March 2006 saw the completion of the Software Enabled Control program sponsored by the Defense Advanced Research Projects Agency (DARPA). With

931-419: Is the rotor's angular velocity , and R is the rotor radius (about the length of one rotor blade) When the rotor blade is perpendicular to the aircraft and advancing, its tip airspeed V t is the aircraft speed plus relative blade tip speed, or V t = V + u . At mu=1, V is equal to u and the tip airspeed is twice the aircraft speed. At the same position on the opposite side (retreating blade),

980-468: Is therefore a significant reduction of rotor drag, allowing higher aircraft speed A conventional rotor such as the UH-60A has lowest consumption around 75% rpm, but higher aircraft speed (and weight) requires higher rpm. A rotor disk with variable radius is a different way of reducing tip speed to avoid compressibility, but blade loading theory suggests that a fixed radius with varying rpm performs better than

1029-622: The Amber and Gnat 750 (predecessors of the General Atomics MQ-1 Predator ), unmanned aerial vehicle (UAV) systems, as well as the A160 Hummingbird Optimum-Speed Rotor UAV, now a Boeing product. Leading Systems has since gone bankrupt and was bought up by United States defense contractor General Atomics . The CIA secretly purchased five drones (now called the " Gnat ") from them. Karem agreed to produce

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1078-478: The Eurocopter X3 flew. 255 knots (293 mph; 472 km/h). 310 minus 15%. 40 -80% \. The compound autogyro, in which the rotor is supplemented by wings and thrust engine but is not itself powered, has also undergone further refinement by Jay Carter Jr. He flew his CarterCopter in 2005. 150 knots (170 mph; 280 km/h). 1. 50%. By 2013 he had developed its design into a personal air vehicle ,

1127-568: The Robinson R22 light civilian helicopter. By using a proven helicopter airframe, engineers were able to focus on developing systems that could be later transferred to the A160. The Maverick program began in 1998, with the first flight taking place less than a year later in 1999. Although the R22 was a two-seat manned helicopter in its original configuration, the Maverick was significant for never having used

1176-423: The Sikorsky X2 ) solve the problem of lift dissymmetry by having both left and right sides provide near equal lift with less flapping. The X2 deals with the compressibility issue by reducing its rotor speed from 446 to 360 RPM to keep the advancing blade tip below the sound barrier when going above 200 knots. The rotors of conventional helicopters are designed to operate at a fixed speed of rotation, to within

1225-613: The United States Department of Defense Joint Heavy Lift program. In 2018, Karem Aircraft announced a partnership with Uber Air to develop a flying taxi. In October 2019, Karem unveiled the Karem AR40 military helicopter for the Future Attack Reconnaissance Aircraft program. Slowed rotor The slowed rotor principle is used in the design of some helicopters . On a conventional helicopter

1274-490: The rotational speed of the rotor is constant; reducing it at lower flight speeds can reduce fuel consumption and enable the aircraft to fly more economically. In the compound helicopter and related aircraft configurations such as the gyrodyne and winged autogyro , reducing the rotational speed of the rotor and offloading part of its lift to a fixed wing reduces drag , enabling the aircraft to fly faster. Traditional helicopters get both their propulsion and lift from

1323-605: The A160 program as part of a series of contracts with Defense Advanced Research Projects Agency (DARPA), the United States Army , and the United States Navy from 2003. In September 2003, DARPA awarded Frontier a $ 75 million contract for the design, development and testing of four A160s. The A160's rotor includes blades whose stiffness and cross-section vary along their length. Their low loading and rigid, hingeless design allows for changing RPM between 140 and 350 using

1372-615: The A160. In August 2008, the A160T began flight testing what came to be known as the DARPA FORESTER radar system. In August 2009, the A160T was chosen by the US Marine Corps along with the Kaman K-MAX to demonstrate the ability to move 6,000 lb (2,722 kg) of cargo in less than 6 hours for three consecutive days. The A160T successfully completed the re-supply demonstration in early March 2010. In December 2010, NAVAIR awarded

1421-459: The A160T demonstrated its ability to hover out of ground effect (HOGE) at 15,000 feet to meet its DARPA milestone. It then surpassed the milestone during the same flight by repeating the HOGE at 20,000 feet altitude. A week later, starting the night of May 14, the A160T demonstrated its un-refueled endurance capabilities with an 18.7-hour flight, landing with over 90 minutes of fuel still on board. This

1470-568: The Army would keep using the fixed-wing UAVs they already had for the role. Data from Boeing. General characteristics Performance Frontier Aircraft Karem Aircraft, Inc. is an American aerospace manufacturer company with offices in Lake Forest, California ; York, Virginia ; and Victorville, California , founded in 2004 by Abraham Karem as a rapid development firm specializing in advanced tiltrotor transport aircraft. Karem

1519-741: The Special Operations Command was turning over its A160s to the Army in 2011. A further crash caused by vibration occurred at Victorville on April 17, 2012, damaging the ARGUS sensor and the aircraft. The A160 was to be deployed to Afghanistan with the ARGUS-IS camera in June 2012. But just before deployment, the Army issued a stop-work order to Boeing because the aircraft had a high "probability of continued technical and schedule delays," and costs and risks had "increased so significantly that program continuation

Boeing A160 Hummingbird - Misplaced Pages Continue

1568-538: The aircraft forward speed V divided by its relative blade tip speed. Upper mu limit is a critical design factor for rotorcraft, and the optimum for traditional helicopters is around 0.4. The "relative blade tip speed" u is the tip speed relative to the aircraft (not the airspeed of the tip). Thus the formula for Advance ratio is μ = V u = V Ω ⋅ R {\displaystyle \mu ={\frac {V}{u}}={\frac {V}{\Omega \cdot R}}} where Omega (Ω)

1617-405: The angle of attack can therefore give a significant reduction in rotor drag, allowing lower fuel consumption. Technical parameters given for each type listed: When Juan de la Cierva developed the autogyro through the 1920s and 1930s, it was found that the tip speeds of the advancing rotor blade could become excessive. Designers such as he and Harold F. Pitcairn developed the idea of adding

1666-522: The autonomous flight control system with the Maverick-A, a modified Robinson R22. This test bed was lost during a crash in 2000, after having flown for 215 hours. The first prototype, a three-blade A160, demonstrated a brief hover on December 7, 2001, and performed its first forward flight on January 29, 2002. A four-blade version of the A160 flew in November 2002 using a Subaru four-cylinder engine, and later

1715-552: The ground then rolled on its side. In August 2010, the A160T underwent jungle test flights in Belize for the U.S. Special Operations Command. Two airframes were involved in tests of the ability of DARPA FORESTER foliage-penetrating radar to penetrate jungle cover. The tests were stopped one week early when one aircraft crashed on September 4, 2010, at the Central Farm airfield in Cayo, Belize as

1764-404: The helicopter to crash near the end of the flight and flight testing continued some months later after the crash investigation was concluded. On November 30, 2005, the aircraft successfully completed its first flight with a new 290 kW (390 hp) 6-cylinder gasoline-powered piston engine, hovering about the airfield for about half an hour. A follow-up turboshaft -powered version, the A160T,

1813-596: The help of researchers from UC Berkeley , MIT , and Georgia Tech , Boeing developed a variant of its Maverick UAV platform which became known as the Renegade UAV. This aircraft successfully performed various maneuvers and flew routes without real-time human input. The development program for the A160 began when DARPA awarded a 30-month technology demonstration contract to San Diego–based Frontier Systems in March 1998, owned by UAV pioneer Abe Karem . In June 1999, Frontier tested

1862-612: The incident was caused when sensor data stopped being updated to the flight computer: with the feedback loop for the control system effectively cut, the helicopter "departed controlled flight and impacted the ground at a near-vertical angle." Much of the forensic evidence was burned in the post-crash fire. A number of potential areas that could have caused the software feedback update thread to stop were found, and those known problem areas were addressed and flight testing resumed on March 26, 2008. On May 9, 2008, at Yuma Proving Ground in Arizona ,

1911-578: The lift came from the wings and 40% from the rotor. At the same time, the US Air Force was investigating fast VTOL aircraft. McDonnell developed what became the McDonnell XV-1 , the first of the V-designated types, which flew in 1955. It was a tip-jet driven gyrodyne, which turned off rotor thrust at high airspeeds and relied on a pusher propeller to maintain forward flight and rotor autorotation. Lift

1960-782: The main rotor; by using a dedicated propulsion device such as a propeller or jet engine , the rotor burden is lessened. If wings are also used to lift the aircraft, the rotor can be unloaded (partially or fully) and its rotational speed further reduced, enabling higher aircraft speed. Compound helicopters use these methods, but the Boeing A160 Hummingbird shows that rotor-slowing is possible without wings or propellers, and regular helicopters may reduce turbine RPM (and thus rotor speed) to 85% using 19% less power. Alternatively, research suggests that twin-engine helicopters may decrease fuel consumption by 25%-40% when running only one engine, given adequate height and velocity well inside

2009-399: The retreating blade is not well understood, however some research has been conducted, particularly for scaled rotors. The US Army Aviation Applied Technology Directorate runs a supporting program in 2016 aiming at developing transmissions with a 50% rotor speed reduction. The profile drag of a rotor corresponds to the cube of its rotational speed . Reducing the rotational speed

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2058-427: The safe areas of the height–velocity diagram . As of 2012, no compound or hybrid wing/rotor (manned) aircraft had been produced in quantity, and only a few had been flown as experimental aircraft, mainly because the increased complexities have not been justified by military or civilian markets. Varying the rotor speed may induce severe vibrations at specific resonance frequencies. Contra-rotating rotors (as on

2107-539: The state of the art theory still gave unrealistically low values for rotor drag. Fairey Aviation in the UK worked on gyrodynes in the late 1940s and 1950s developing tip-jet propulsion which eliminated the need for countertorque. They culminated in the Fairey Rotodyne , the prototype for a VTOL passenger aircraft, which could combine the vertical landing of a helicopter with the speed of a fixed wing aircraft. The Rotodyne had

2156-543: The tip airspeed is the aircraft speed minus relative blade tip speed, or V t = V - u . At mu=1, the tip airspeed is zero. At a mu between 0.7 and 1.0, most of the retreating side has reverse airflow. Although rotor characteristics are fundamental to rotorcraft performance, little public analytical and experimental knowledge exists between advance ratios of 0.45 to 1.0, and none is known above 1.0 for full-size rotors. Computer simulations are not capable of adequate predictions at high mu. The region of reverse flow on

2205-556: Was first flown on June 15, 2007. It was flown for 8 hours on September 27, 2007 while carrying a 1,000-pound payload. On October 12 it flew for 12 hours while carrying a 500-pound payload, simulating a multi-sensor military reconnaissance mission. This latter flight used up less than 60% of the Hummingbird's maximum fuel load. On December 10, 2007, one of the A160T prototypes crashed during a flight test at Boeing Advanced Systems' test facility in Victorville. A Boeing investigation determined

2254-484: Was no longer in the best interest of the government." Vibration was among the issues. The stop-work order left the A160 still officially developmental, but close to termination. By December 2012, the Army Training and Doctrine Command had reviewed the Army's idea for a VTOL helicopter UAV for ISR missions and decided that, because of budget constraints, they would not continue to pursue the idea. They instead decided that

2303-630: Was recognized as the longest un-refueled flight of any rotorcraft, and the Fédération Aéronautique Internationale (FAI) awarded Boeing the official endurance record in the 500 kg to 2,500 kg autonomously controlled UAV class for the flight. Earlier, in May 2004, the U.S. Army Communications-Electronics Command awarded Syracuse Research Corp. a $ 13.3 million contract for the ultra high frequency, foliage penetrating, real-time moving target indicator/synthetic aperture radar for use in

2352-467: Was shared between the rotor and stub wings. It established a rotorcraft speed record of 170 knots (200 mph; 310 km/h). 0.95. 180-410 (50% ). 85% \ 15%. 6.5 (Wind tunnel tests at 180 RPM with no propeller. ) The Lockheed AH-56 Cheyenne military attack helicopter for the US Army arose out of Lockheed's ongoing research programme into rigid rotors, which began with the CL-475 in 1959. Stub wings and

2401-569: Was the former chief designer for the Israeli Air Force — who built his first drone during 1973's Yom Kippur War — and has been described by The Economist as the man who "created the robotic plane that transformed the way modern warfare is waged — and continues to pioneer other airborne innovations". He emigrated to the United States in the late 1970s. Under his previous company, Leading Systems Inc. (LSI), Karem led teams that developed

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