106-579: The Northrop Grumman X-47B is a demonstration unmanned combat aerial vehicle (UCAV) designed for aircraft carrier -based operations. Developed by the American defense technology company Northrop Grumman , the X-47 project began as part of DARPA 's J-UCAS program, and subsequently became part of the United States Navy 's Unmanned Combat Air System Demonstration (UCAS-D) program. The X-47B
212-399: A V-tail configuration, are used to move the boom by creating aerodynamic forces. They are actuated hydraulically and controlled by the boom operator using a control stick. The boom operator also telescopes the boom to make the connection with the receiver's receptacle. To complete an aerial refueling, the tanker and receiver aircraft rendezvous, flying in formation. The receiver moves to
318-520: A carrier air wing ) to extend the range of its strike aircraft. In other cases, using the buddy store method allows a carrier -based aircraft to take-off with a heavier than usual load less fuel than might be necessary for its tasking. The aircraft would then topped-up with fuel from an HDU-equipped "buddy" tanker, a method previously used by the Royal Navy in operating its Supermarine Scimitar , de Havilland Sea Vixen , and Blackburn Buccaneers ; in
424-509: A 15-month concept-exploration program. Design considerations for a naval UCAV included dealing with the corrosive saltwater environment, deck handling for launch and recovery, command and control system integration, and operation in an aircraft carrier's high- electromagnetic -interference environment. The Navy was interested in using UCAVs for reconnaissance, to penetrate protected airspace and identify targets for follow-on attacks. Northrop Grumman's proof-of-concept X-47A Pegasus , which provided
530-455: A Hose Drum Unit (HDU). When not in use, the hose/drogue is reeled completely into the HDU. The receiver has a probe , which is a rigid, protruding or pivoted retractable arm placed on the aircraft's nose or fuselage to make the connection. Most modern versions of the probe are usually designed to be retractable, and are retracted when not in use, particularly on high-speed aircraft. At the end of
636-587: A Return-To-Launch-Site abort capability if necessary. At its most efficient altitude and speed, the Blackbird was capable of flying for many hours without refueling. The SR-71 used a special fuel, JP-7 , with a very high flash point to withstand the extreme skin temperatures generated during Mach 3+ cruise flight. While JP-7 could be used by other aircraft, its burn characteristics posed problems in certain situations (such as high-altitude, emergency engine starts) that made it less than optimal for aircraft other than
742-540: A boom system followed quickly in the autumn of 1948. The first use of aerial refueling in combat took place during the Korean War, involving F-84 fighter-bombers flying missions from Japanese airfields, due to Chinese-North Korean forces overrunning many of the bases for jet aircraft in South Korea, refueling from converted B-29s using the drogue-and-probe in-flight refueling system with the probe located in one of
848-580: A feat made possible by four aerial refuelings from four pairs of KB-29M tankers of the 43d ARS. Before the mission, crews of the 43rd had experienced only a single operational air refueling contact. The flight started and ended at Carswell Air Force Base in Fort Worth, Texas with the refuelings accomplished over the Azores , Saudi Arabia , the Pacific Ocean near Guam , and between Hawaii and
954-403: A flexible hose that trails from the tanker aircraft. The drogue (or para-drogue ), sometimes called a basket , is a fitting resembling a shuttlecock , attached at its narrow end (like the "cork" nose of a shuttlecock) with a valve to a flexible hose. The drogue stabilizes the hose in flight and provides a funnel to aid insertion of the receiver aircraft probe into the hose. The hose connects to
1060-404: A four-aircraft strike package. USAF KC-135 and French Air Force KC-135FR refueling-boom equipped tankers can be field-converted to a probe-and-drogue system using a special adapter unit. In this configuration, the tanker retains its articulated boom, but has a hose/drogue at the end of it instead of the usual nozzle. The tanker boom operator holds the boom still while the receiver aircraft flies
1166-493: A hose-and-drogue system, dubbed UPAZ, and thus later Russian aircraft may be equipped with probe and drogue. The Chinese PLAF has a fleet of Xian H-6 bombers modified for aerial refueling, and plans to add Russian Ilyushin Il-78 aerial refueling tankers. Tankers can be equipped with multipoint hose-and-drogue systems, allowing them to refuel two (or more) aircraft simultaneously, reducing time spent refueling by as much as 75% for
SECTION 10
#17327869639321272-416: A much smaller position-keeping tolerance, staying properly connected to a KC-135 adapter unit is considerably more difficult than staying in a traditional hose/drogue configuration. When fueling is complete, the receiver carefully backs off until the probe refueling valve disconnects from the valve in the basket. Off center disengagements, like engagements, can cause the drogue to "prang" the probe and/or strike
1378-444: A new jet endurance record. FRL still exists as part of Cobham plc . Modern specialized tanker aircraft have equipment specially designed for the task of offloading fuel to the receiver aircraft, based on drogue and probe, even at the higher speeds modern jet aircraft typically need to remain airborne. In January 1948, General Carl Spaatz, then the first Chief of Staff of the new United States Air Force , made aerial refueling
1484-484: A pioneer of long-distance aviation. During the 1920s, he made long-distance flights to places as far afield as Africa and Australia and he began experimenting with the possibilities of in-flight refueling to extend the range of flight. Cobham was one of the founding directors of Airspeed Limited , an aircraft manufacturing company that went on to produce a specially-adapted Airspeed Courier that Cobham used for his early experiments with in-flight refueling. This craft
1590-407: A position behind the tanker, within safe limits of travel for the boom, aided by director lights or directions radioed by the boom operator. Once in position, the operator extends the boom to make contact with the receiver aircraft. Once in contact, fuel is pumped through the boom into the receiver aircraft. While in contact, the receiver pilot must continue to fly within the "air refueling envelope",
1696-522: A series of tests, including arrested landings and catapult launches, to validate its ability to conduct precision approaches to an aircraft carrier. Its first land-based catapult launch was conducted successfully on 29 November 2012. On 26 November 2012, the X-47B began its carrier-based evaluation aboard the USS ; Harry S. Truman (CVN-75) at Naval Station Norfolk , Virginia. On 18 December 2012,
1802-584: A similar dropped line from the receiver, allowing the refueling to commence. In 1935, Cobham sold off the airline Cobham Air Routes Ltd to Olley Air Service and turned to the development of inflight refueling, founding the company Flight Refuelling Ltd . Atcherly's system was bought up by Cobham's company, and with some refinement and continuous improvement through the late '30s, it became the first practical refueling system. Sir Alan Cobham 's grappled-line looped-hose air-to-air refueling system borrowed from techniques patented by David Nicolson and John Lord, and
1908-417: A single mission, without landing to install an adapter. Other tankers are equipped with hose-and-drogue attachments that do not interfere with the operation of the centerline boom: many KC-135s are equipped with dual under-wing attachments known as Multi-point Refueling System (MPRSs), while some KC-10s and A330 MRTTs have similar under-wing refueling pods (referred to as Wing Air Refueling Pods or WARPs on
2014-509: A small number of FRL looped-hose units and fitted a number of B-29s as tankers to refuel specially equipped B-29s and later B-50s. The USAF made only one major change in the system used by the RAF. The USAF version had auto-coupling of the refueling nozzle, where the leader line with the refueling hose is pulled to the receiver aircraft and a refueling receptacle on the belly of the aircraft, allowing high-altitude air-to-air refueling and doing away with
2120-575: A squadron of Javelin air defense aircraft was refueled in stages from the UK to India and back (exercise "Shiksha"). After the retirement of the Valiant in 1965, the Handley Page Victor took over the UK refueling role and had three hoses (HDUs). These were a fuselage-mounted HDU and a refueling pod on each wing. The center hose could refuel any probe-equipped aircraft, the wing pods could refuel
2226-434: A stand-alone form of computer art. Sales Engineering staff, often bearing the title Sales Engineer or Presales Consultant, will prepare technology demonstrations for business meetings or seminars to show capabilities of business products. This can include both software and hardware products, and can show multiple products integrating together. Usually, a demonstration is less than a Proof of concept , but can come some of
SECTION 20
#17327869639322332-564: A three-year test program with 50 tests at Edwards AFB and NAS Patuxent River, Maryland , culminating in sea trials in 2013. However, they performed so consistently that preliminary tests ended after 16 flights. The Navy decided to have them demonstrate carrier launches and recoveries, as well as autonomous inflight refueling with a probe and drogue . In November 2011, the Navy announced that aerial refuelling equipment and software would be added to one X-47B in 2014 for testing; they also affirmed that
2438-600: A top priority of the service. In March 1948, the USAF purchased two sets of FRL's looped-hose in-flight refueling equipment, which had been in practical use with British Overseas Airways Corporation (BOAC) since 1946, and manufacturing rights to the system. FRL also provided a year of technical assistance. The sets were immediately installed in two Boeing B-29 Superfortresses , with plans to equip 80 B-29s. Flight testing began in May 1948 at Wright-Patterson Air Force Base , Ohio , and
2544-578: A total of 16 precision approaches to the carrier flight deck, including five tests of wave-off functions, nine touch-and-go landings, two arrested landings, and three catapult launches. On 10 November 2013, testing continued on board the USS Theodore Roosevelt (CVN-71) . During this phase, the X-47B's digitized carrier-controlled environment was tested, such as between the UAV and carrier personnel during launching, recovering, and flight operations. Trials on Theodore Roosevelt in 2014 were intended to test
2650-518: A variety of follow-on evaluations. In January 2017, the first X-47B departed NAS Patuxent River, Md. for Northrop Grumman's manufacturing plant in Palmdale, Calif. In August 2017, Aviation Week published photos of a modified X-47B as a testbed for Northrop Grumman's MQ-25 bid. On 25 October 2017, the company announced its withdrawal from the MQ-25 competition, saying it would be unable to operate under
2756-413: Is a prototype , rough example or otherwise incomplete version of a conceivable product or future system, put together as proof of concept with the primary purpose of showcasing the possible applications, feasibility, performance and method of an idea for a new technology. They can be used as demonstrations to the investors , partners, journalists or even to potential customers in order to convince them of
2862-461: Is a tailless jet -powered blended-wing-body aircraft capable of semi-autonomous operation and aerial refueling . The X-47B first flew in 2011, and as of 2015, its two active demonstrators have undergone extensive flight and operational integration testing, having successfully performed a series of land- and carrier-based demonstrations. In August 2014, the US Navy announced that it had integrated
2968-472: Is not compatible with flying boom equipment, creating a problem for military planners where mixed forces are involved. Incompatibility can also complicate the procurement of new systems. The Royal Canadian Air Force currently wish to purchase the F-35A , which can only refuel via the flying boom, but only possess probe-and-drogue refuelers . The potential cost of converting F-35As to probe-and-drogue refueling (as
3074-447: Is relatively light (typically soft canvas webbing) and subject to aerodynamic forces, it can be pushed around by the bow wave of approaching aircraft, exacerbating engagement even in smooth air. After initial contact, the hose and drogue is pushed forward by the receiver a certain distance (typically, a few feet), and the hose is reeled slowly back onto its drum in the HDU. This opens the tanker's main refueling valve allowing fuel to flow to
3180-618: Is the process of transferring aviation fuel from one aircraft (the tanker ) to another (the receiver) while both aircraft are in flight. The two main refueling systems are probe-and-drogue , which is simpler to adapt to existing aircraft and the flying boom , which offers faster fuel transfer, but requires a dedicated boom operator station. The procedure allows the receiving aircraft to remain airborne longer, extending its range or loiter time. A series of air refuelings can give range limited only by crew fatigue /physical needs and engineering factors such as engine oil consumption. Because
3286-479: Is used on US Navy & Marine Corps F-35Bs and F-35Cs ) added to the early-2010s political controversy which surrounded F-35 procurement within the RCAF. These concerns can be addressed by drogue adapters (see section "Boom drogue adapter units" above) that allow drogue aircraft to refuel from boom-equipped aircraft, and by refuelers that are equipped with both drogue and boom units and can thus refuel both types in
Northrop Grumman X-47B - Misplaced Pages Continue
3392-709: The Aéro-Club de France and the 34th Aviation Regiment of the French Air Force were able to demonstrate passing fuel between machines at the annual aviation fete at Vincennes in 1928. The UK's Royal Aircraft Establishment was also running mid-air refueling trials, with the aim to use this technique to extend the range of the long-distance flying boats that serviced the British Empire . By 1931 they had demonstrated refueling between two Vickers Virginias , with fuel flow controlled by an automatic valve on
3498-618: The Short Empire flying boat Cambria from an Armstrong Whitworth AW.23 . Handley Page Harrows were used in the 1939 trials to perform aerial refueling of the Empire flying boats for regular transatlantic crossings. From 5 August to 1 October 1939, sixteen crossings of the Atlantic were made by Empire flying boats, with fifteen crossings using FRL's aerial refueling system. After the sixteen crossings further trials were suspended due to
3604-478: The USS George H.W. Bush (CVN-77) on 14 May 2013 in the Atlantic Ocean , marking the first time that a UAV was catapulted off an aircraft carrier. On 17 May 2013, another first was achieved when it performed touch-and-go landings and take-offs from George H.W. Bush while underway. On 10 July 2013, the X-47B launched from Patuxent River and landed on the deck of George H.W. Bush , conducting
3710-476: The West Coast . Cobham's company FRL soon realized that their looped-hose system left much to be desired and began work on an improved system that is now commonly called the probe-and-drogue air-to-air refueling system and today is one of the two systems chosen by air forces for air-to-air refueling, the other being the flying-boom system. In post-war trials the RAF used a modified Lancaster tanker employing
3816-433: The "receptacle" in the receiver aircraft during fuel transfer. A poppet valve in the end of the nozzle prevents fuel from exiting the tube until the nozzle properly mates with the receiver's refueling receptacle. Once properly mated, toggles in the receptacle engage the nozzle, holding it locked during fuel transfer. The "flying" boom is so named because flight control surfaces , small movable airfoils that are often in
3922-572: The Blackbird constantly leaked fuel before heating expanded the airframe enough to seal its fuel tanks. Following the supersonic dash the SR-71 would then rendezvous with a tanker to fill its now nearly empty tanks before proceeding on its mission. This was referred to as the LTTR (for "Launch To Tanker Rendezvous") profile. LTTR had the added advantage of providing an operational test of the Blackbird's refueling capability within minutes after takeoff, enabling
4028-582: The Boeing plant at Renton, Washington . Boeing went on to develop the world's first production aerial tanker, the KC-97 Stratofreighter , a piston-engined Boeing Stratocruiser (USAF designation C-97 Stratofreighter ) with a Boeing-developed flying boom and extra kerosene (jet fuel) tanks feeding the boom. The Stratocruiser airliner itself was developed from the B-29 bomber after World War II . In
4134-509: The Buccaneer's case using a bomb-bay-mounted tank and HDU. The tanker aircraft flies straight and level and extends the hose/drogue, which is allowed to trail out behind and below the tanker under normal aerodynamic forces. The pilot of the receiver aircraft extends the probe (if required) and uses normal flight controls to "fly" the refueling probe directly into the basket. This requires a closure rate of about two knots (walking speed) to push
4240-452: The F-84's wing-tip fuel tanks. The flying boom is a rigid, telescoping tube with movable flight control surfaces that a boom operator on the tanker aircraft extends and inserts into a receptacle on the receiving aircraft. All boom-equipped tankers (e.g. KC-135 Stratotanker , KC-10 Extender , KC-46 Pegasus ) have a single boom and can refuel one aircraft at a time with this mechanism. In
4346-405: The HDU. If the hose is pushed in too far or not far enough, a cutoff switch will inhibit fuel flow, which is typically accompanied by an amber light. Disengagement is commanded by the tanker pilot with a red light. The US Navy , Marine Corps , and some Army aircraft refuel using the "hose-and-drogue" system, as do most aircraft flown by western European militaries. The Soviet Union also used
Northrop Grumman X-47B - Misplaced Pages Continue
4452-457: The KC-10). A small number of Soviet Tu-4s and Tu-16s (the tanker variant was Tu-16Z). used a wing-to-wing method. Similar to the probe-and-drogue method but more complicated, the tanker aircraft released a flexible hose from its wingtip. An aircraft flying alongside had to catch the hose with a special lock under its wingtip. After the hose was locked and the connection was established, the fuel
4558-452: The KC-97, the mixed gasoline/kerosene fuel system was clearly not desirable and it was obvious that a jet-powered tanker aircraft would be the next development, having a single type of fuel for both its own engines and for passing to receiver aircraft. The 230 mph (370 km/h) cruise speed of the slower, piston-engined KC-97 was also a serious issue, as using it as an aerial tanker forced
4664-521: The Navy's fiscal 2014 budget, but the X-47B nonetheless conducted a successful autonomous refuelling demonstration in April 2015. After the USAF made plans for a next generation bomber following the 2006 Quadrennial Defense Review, Northrop Grumman proposed a variety of derivatives based on the X-47B, informally called "X-47C" by the company. One iteration was a bomber to have a payload of 10,000 pounds (4,500 kg) of bombs, significantly exceeding that of
4770-417: The UAV's ability to swiftly take off, land, and hold in a pattern among manned aircraft without disrupting carrier operations. It also used a jet-blast deflector on deck for the first time, enabling takeoff without impacting operations behind it. On 10 April 2014, the X-47B performed its first night flight. On 17 August 2014, it took off and landed on Theodore Roosevelt alongside an F/A-18 Hornet , marking
4876-562: The USAF to build jet tankers based on the Boeing 367-80 (Dash-80) airframe. The result was the Boeing KC-135 Stratotanker , of which 732 were built. The flying boom is attached to the rear of the tanker aircraft. The attachment is gimballed , allowing the boom to move with the receiver aircraft. The boom contains a rigid pipe to transfer fuel. The fuel pipe ends in a nozzle with a flexible ball joint. The nozzle mates to
4982-522: The USSR first had it been ordered to do so. The bombers would fly orbits around their assigned positions from which they were to enter Soviet airspace if they received the order, and the tankers would refill the bombers' fuel tanks so that they could keep a force in the air 24 hours a day, and still have enough fuel to reach their targets in the Soviet Union. This also ensured that a first strike against
5088-882: The X-47A. Although Northrop Grumman estimated that the X-47C could enter service in 2018, the NGB program was shelved in 2010. Original proof-of-concept prototype with a 27.8-foot (8.5 m) wingspan, first flown in 2003. Demonstrator aircraft with a 62-foot (19 m) wingspan, first flown in 2011. Proposed larger version intended for the Navy's UCLASS project or as an Air Force straegic bomber. Data from General characteristics Performance Armament Avionics Related development Aircraft of comparable role, configuration, and era Related lists Technology demonstration A technology demonstration (or tech demo ), also known as demonstrator model ,
5194-432: The X-47B completed its first at-sea test phase; it was remarked to have performed "outstandingly", having proved compatible with the flight deck , hangar bays, and communication systems of an aircraft carrier. With deck testing completed, the X-47B returned to NAS Patuxent River for further tests. On 4 May 2013, it successfully performed an arrested landing on a simulated carrier deck at Patuxent River. The X-47B launched from
5300-467: The X-47B from a surveillance and strike aircraft into a reconnaissance and aerial refuelling drone with "limited strike capability". The change followed a top-level review and restructuring of the now-defunct unmanned carrier-launched airborne surveillance and strike (UCLASS) project, with later budgets instead funding the MQ-25 Stingray carrier-based aerial refuelling system (CBARS). The project
5406-476: The X-47B into carrier operations alongside manned aircraft, and by May 2015 the primary test program was declared complete. The X-47B demonstrators themselves were intended to become museum exhibits after completing flight testing, but the Navy later decided to maintain them in flying condition pending further development. The US Navy did not commit to practical UCAS efforts until 2000, when it awarded contracts of US$ 2 million each to Boeing and Northrop Grumman for
SECTION 50
#17327869639325512-508: The X-47B to demonstrate unmanned aerial refueling capabilities. On 28 August 2013, a Calspan-flown Learjet 25 refueled from a Boeing 707 tanker while flying autonomously as a surrogate aircraft uploaded with the X-47B's technology. The test was to demonstrate that unmanned and optionally manned aircraft can have an automated aerial refueling capability, significantly increasing their range, persistence, and flexibility. Plans to further demonstrate autonomous aerial refueling were reportedly cut in
5618-554: The X-47B won the 57th Annual Laureate Award for "extraordinary achievements" in aeronautics and propulsion hosted by Aviation Week . On 9 April 2014, the National Aeronautic Association selected Northrop Grumman, the United States Navy, and the X-47B's development team as the joint recipients of the 2013 Collier Trophy for excellence in aeronautic technology. The Navy used software from
5724-414: The X-47B's fifth test period at sea, having completed eight catapult launches from a carrier, 30 touch-and-goes, and seven arrested landings aboard George H.W. Bush and Theodore Roosevelt . Testing was successfully completed on 24 August 2014, with the X-47B completing five catapult launches, four arrestments, and nine touch-and-go landings; nighttime taxi and deckhandling operations were also performed for
5830-452: The X-47B. In February 2015, the Navy stated that the competition for private tenders for constructing the UCLASS fleet would begin in 2016, with the aircraft expected to enter service in the early 2020s. Reportedly, despite the X-47B's success in test flights, officials were concerned that it would be too costly and insufficiently stealthy for the needs of the UCLASS project. In April 2015, it
5936-501: The aircraft having to fly to a lower altitude to be depressurized so a crew member could manually do the coupling. This air-to-air refueling system was used by the B-50 Superfortress Lucky Lady II of the 43rd Bomb Wing to make its famous first non-stop around-the-world flight in 1949. From 26 February to 3 March 1949, Lucky Lady II flew non-stop around the world in 94 hours and 1 minute,
6042-483: The aircraft made its mission impossible without aerial refueling. Based at Beale AFB in central California , SR-71s had to be forward-deployed to Europe and Japan prior to flying actual reconnaissance missions. These trans-Pacific and trans-Atlantic flights during deployment were impossible without aerial refueling. The SR-71's designers traded takeoff performance for better high-speed, high-altitude performance, necessitating takeoff with less-than-full fuel tanks from even
6148-408: The aircraft to be refueled (very close "line astern" formation flying) has resulted in the activity only being used in military operations ; there are no regular civilian in-flight refueling activities. Originally trialed shortly before World War II on a limited scale to extend the range of British civilian transatlantic flying boats , and then employed after World War II on a large scale to extend
6254-449: The aircraft's fuselage and causing damage. The other major difference with this system is that when contacted, the hose does not "retract" into an HDU. Instead, the hose bends depending on how far it is pushed toward the boom. If it is pushed too far, it can loop around the probe or nose of the aircraft, damage the windscreen, or cause contact with the rigid boom. If not pushed far enough, the probe will disengage, halting fueling. Because of
6360-409: The aircraft's fuselage. Some tankers have both a boom and one or more complete hose-and-drogue systems. The USAF KC-10 has both a flying boom and a separate hose-and-drogue system manufactured by Cobham . Both are on the aircraft centerline at the tail of the aircraft, so only one can be used at once. However, such a system allows all types of probe- and receptacle-equipped aircraft to be refueled in
6466-416: The area in which contact with the boom is safe. Moving outside of this envelope can damage the boom or lead to mid-air collision, for example the 1966 Palomares B-52 crash . If the receiving aircraft approaches the outer limits of the envelope, the boom operator will command the receiver pilot to correct their position and disconnect the boom if necessary. When the desired amount of fuel has been transferred,
SECTION 60
#17327869639326572-538: The basis for the X-47B, first flew in 2003. The J-UCAS program was terminated in February 2006 following the Quadrennial Defense Review . The US Air Force and Navy proceeded with their own UAV programs. The Navy selected Northrop Grumman's X-47B as its unmanned combat air system demonstrator (UCAS-D) program. To provide realistic testing, the demonstrator was built to be the same size and weight as
6678-574: The bombers' airfields could not obliterate the US's ability to retaliate by bomber. In 1958, Valiant tankers in the UK were developed with one HDU mounted in the bomb-bay. Valiant tankers of 214 Squadron were used to demonstrate radius of action by refueling a Valiant bomber non-stop from UK to Singapore in 1960 and a Vulcan bomber to Australia in 1961. Other UK exercises involving refueling aircraft from Valiant tankers included Javelin and Lightning fighters, also Vulcan and Victor bombers. For instance, in 1962
6784-528: The brothers John, Kenneth, Albert, and Walter Hunter set a new record of 553 hours 40 minutes over Chicago using two Stinson SM-1 Detroiters as refueler and receiver. Aerial refueling remained a very dangerous process until 1935, when brothers Fred and Al Key demonstrated a spill-free refueling nozzle, designed by A. D. Hunter . They exceeded the Hunters' record by nearly 100 hours in a Curtiss Robin monoplane, staying aloft for more than 27 days. The US
6890-403: The demonstrators would never be armed. In 2012, Northrop Grumman tested a wearable remote control system , designed to allow ground crews to steer the X-47B while on the carrier deck. In May 2012, AV-1 began high-intensity electromagnetic interference testing at Patuxent River, to test compatibility with planned electronic warfare systems. In June 2012, AV-2 arrived at Patuxent River to begin
6996-585: The development of Alexander P. de Seversky , between two planes occurred on 25 June 1923, between two Airco DH-4B biplanes of the United States Army Air Service . An endurance record was set by three DH-4Bs (a receiver and two tankers) on 27–28 August 1923, in which the receiver airplane remained aloft for more than 37 hours using nine mid-air refueling to transfer 687 US gallons (2,600 L) of aviation gasoline and 38 US gallons (140 L) of engine oil. The same crews demonstrated
7102-402: The drogue under the appropriate pressure (assuming the tanker crew has energized the pump). Tension on the hose is aerodynamically 'balanced' by a motor in the HDU so that as the receiver aircraft moves fore and aft, the hose retracts and extends, thus preventing bends in the hose that would cause undue side loads on the probe. Fuel flow is typically indicated by illumination of a green light near
7208-552: The first ever arrested landing of a UAV on a carrier at sea. It subsequently completed a second successful arrested landing on George H.W. Bush , but a third attempt was diverted to the Wallops Flight Facility in Virginia due to a technical issue. One of the UAV's three navigational sub-systems failed, which was identified by the other two sub-systems and indicated to the operator, who followed procedures to abort
7314-467: The first time a UAV operated in conjunction with manned aircraft aboard an aircraft carrier. The Hornet launched from the carrier, followed by the X-47B. After a brief flight, the X-47B touched down and immediately took off again to verify system behavior. After 24 minutes, the X-47B landed on the flight deck and taxied away to give the Hornet room to land. The demonstration met all test objectives, and marked
7420-413: The first time. It met its objective of performing launches and recoveries at 90-second intervals with manned Hornets. In April 2015, the X-47B successfully conducted the world's first fully autonomous aerial refuelling with an Omega Air KC-707 tanker over the coast of Maryland . This marked the completion of all primary demonstration tasks required of it. In February 2016, the Navy decided to repurpose
7526-554: The flying boom system, along with Australia (KC-30A), the Netherlands (KDC-10), Israel (modified Boeing 707), Japan (KC-767), Turkey (KC-135Rs), and Iran (Boeing 707 and 747). The system allows higher fuel flow rates (up to 1,000 US gallons (3,800 L) / 6,500 pounds (2,900 kg) per minute for the KC-135, but does require a boom operator, and can only refuel one aircraft at a time. The probe-and-drogue refueling method employs
7632-399: The hose several feet into the HDU and solidly couple the probe and drogue. Too little closure will cause an incomplete connection and no fuel flow (or occasionally leaking fuel). Too much closure is dangerous because it can trigger a strong transverse oscillation in the hose, severing the probe tip. The optimal approach is from behind and below (not level with) the drogue. Because the drogue
7738-458: The hose was connected, the tanker climbed sufficiently above the receiver aircraft to allow the fuel to flow under gravity. When Cobham was developing his system, he saw the need as purely for long-range transoceanic commercial aircraft flights, but modern aerial refueling is used exclusively by military aircraft. In 1934, Cobham had founded Flight Refuelling Ltd (FRL) and by 1938 had used its looped-hose system to refuel aircraft as large as
7844-460: The hose which would cut off if contact was lost. Royal Air Force officer Richard Atcherley had observed the dangerous aerial-refueling techniques in use at barnstorming events in the US and determined to create a workable system. While posted to the Middle East he developed and patented his 'crossover' system in 1934, in which the tanker trailed a large hooked line that would reel in
7950-457: The landing. The Navy stated that the problem's detection demonstrated the X-47B's reliability and ability to operate autonomously. On 15 July 2013, the second X-47B, designated 501, was forced to abort another planned landing on George H.W. Bush due to technical issues. Officials asserted that the program only required one successful at-sea landing, though testers were aiming for three, while two out of four were achieved. The Navy continued flying
8056-478: The late 1940s, General Curtis LeMay , commander of the Strategic Air Command (SAC), asked Boeing to develop a refueling system that could transfer fuel at a higher rate than had been possible with earlier systems using flexible hoses, resulting in the flying boom system. The B-29 was the first to employ the boom, and between 1950 and 1951, 116 original B-29s, designated KB-29Ps, were converted at
8162-432: The longest runways. Once airborne, the Blackbird would accelerate to supersonic speed using afterburners to facilitate structural heating and expansion. The magnitude of temperature changes experienced by the SR-71, from parked to its maximum speed, resulted in significant expansion of its structural parts in cruise flight. To allow for the expansion, the Blackbird's parts had to fit loosely when cold, so loosely, in fact, that
8268-475: The more maneuverable fighter/ground attack types. A byproduct of this development effort and the building of large numbers of tankers was that these tankers were also available to refuel cargo aircraft , fighter aircraft , and ground attack aircraft , in addition to bombers, for ferrying to distant theaters of operations. This was much used during the Vietnam War , when many aircraft could not have covered
8374-527: The much improved probe-and-drogue system, with a modified Gloster Meteor F.3 jet fighter, serial EE397 , fitted with a nose-mounted probe. On 7 August 1949, the Meteor flown by FRL test pilot Pat Hornidge took off from Tarrant Rushton and remained airborne for 12 hours and 3 minutes, receiving 2,352 imperial gallons (10,690 L) of fuel in ten refuelings from a Lancaster tanker. Hornidge flew an overall distance of 3,600 mi (5,800 km), achieving
8480-404: The newer jet-powered military aircraft to slow down to mate with the tanker's boom, a highly serious issue with the newer supersonic aircraft coming into service at that time, which could force such receiving aircraft in some situations to slow down enough to approach their stall speed during the approach to the tanker. It was no surprise that, after the KC-97, Boeing began receiving contracts from
8586-506: The outbreak of World War II. During the closing months of World War II, it had been intended that Tiger Force 's Lancaster and Lincoln bombers would be in-flight refueled by converted Halifax tanker aircraft, fitted with the FRL's looped-hose units, in operations against the Japanese homelands , but the war ended before the aircraft could be deployed. After the war ended, the USAF bought
8692-445: The probe into the basket. Unlike the soft canvas basket used in most drogue systems, the adapter units use a steel basket, grimly known as the "iron maiden" by naval aviators because of its unforgiving nature. Soft drogues can be contacted slightly off center, wherein the probe is guided into the hose receptacle by the canvas drogue. The metal drogue, when contacted even slightly off center, will pivot out of place, potentially "slapping"
8798-585: The probe is a valve that is closed until it mates with the drogue's forward internal receptacle, after which it opens and allows fuel to pass from tanker to receiver. The valves in the probe and drogue that are most commonly used are to a NATO standard and were originally developed by the company Flight Refuelling Limited in the UK and deployed in the late 1940s and 1950s. This standardization enables drogue-equipped tanker aircraft from many nations to refuel probe-equipped aircraft from other nations. The NATO-standard probe system incorporates shear rivets that attach
8904-561: The projected operational craft, with a full-sized weapons bay capable of carrying existing missiles. The X-47B industry team included subcontractors Lockheed Martin , Pratt & Whitney , GKN Aerospace , Eaton , General Electric , UTC Aerospace Systems , Dell , Honeywell , Moog , Wind River , Parker Aerospace , Sargent Aerospace & Defense , and Rockwell Collins . The X-47B prototype rolled out from Air Force Plant 42 in Palmdale, California , on 16 December 2008. Its first flight
9010-414: The range of strategic bombers , aerial refueling since the Vietnam War has been extensively used in large-scale military operations. Some of the earliest experiments in aerial refueling took place in the 1920s; two slow-flying aircraft flew in formation, with a hose run down from a hand-held fuel tank on one aircraft and placed into the usual fuel filler of the other. The first mid-air refueling, based on
9116-420: The range of 35–40% have been estimated for long-haul flights (including the fuel used during the tanker missions). Usually, the aircraft providing the fuel is specially designed for the task, although refueling pods may be fitted to existing aircraft designs in the case of "probe-and-drogue" systems. The cost of the refueling equipment on both tanker and receiver aircraft and the specialized aircraft handling of
9222-462: The receiver aircraft is topped-off with extra fuel in the air, air refueling can allow a takeoff with a greater payload which could be weapons, cargo, or personnel: the maximum takeoff weight is maintained by carrying less fuel and topping up once airborne. Aerial refueling has also been considered as a means to reduce fuel consumption on long-distance flights greater than 3,000 nautical miles (5,600 km; 3,500 mi). Potential fuel savings in
9328-430: The refueling valve to the end of the probe. This is so that if a large side or vertical load develops while in contact with the drogue, the rivets shear and the fuel valve breaks off, rather than the probe or receiver aircraft suffering structural damage. A so-called "broken probe" (actually a broken fuel valve, as described above) may happen if poor flying technique is used by the receiver pilot, or in turbulence. Sometimes
9434-655: The same flight, such as the KC-10, MPRS KC-135, or Airbus A330 MRTT. The development of the KC-97 and Boeing KC-135 Stratotankers was pushed by the Cold War requirement of the United States to be able to keep fleets of nuclear -armed B-47 Stratojet and B-52 Stratofortress strategic bombers airborne around-the-clock either to threaten retaliation against a Soviet strike for mutual assured destruction , or to bomb
9540-541: The same year, but these early experiments were not yet regarded as a practical proposition, and were generally dismissed as stunts. As the 1920s progressed, greater numbers of aviation enthusiasts vied to set new aerial long-distance records, using inflight air refueling. One such enthusiast, who would revolutionize aerial refueling was Sir Alan Cobham , member of the Royal Flying Corps in World War I , and
9646-412: The terms of the service's request for proposals. A modified Deck Handling System demonstration was planned, but efforts were suspended. One X-47B performed a required upkeep static engine run in spring 2019. The other remained stored in a hangar. The older X-47A Pegasus Air Vehicle was also kept in a covered open air hangar at Palmdale. The general public can not enter the Palmdale facility. In March 2014,
9752-624: The transoceanic distances without aerial refueling, even with intermediate bases such as Hickam Air Force Base , Hawaii and Kadena Air Base , Okinawa. In addition to allowing the transport of the aircraft themselves, the cargo aircraft could also carry matériel , supplies, and personnel to Vietnam without landing to refuel. KC-135s were also frequently used for refueling of air combat missions from air bases in Thailand. The USAF SR-71 Blackbird strategic reconnaissance aircraft made frequent use of air-to-air refueling. Indeed, design considerations of
9858-588: The two X-47Bs through 2014, after it was criticised for prematurely retiring them. The Navy subsequently deployed the X-47Bs to carriers for three further test phases between 2013 and 2015, with the intent of demonstrating that UAVs could seamlessly work with a 70-plane carrier air wing. On 18 September 2013, the X-47B flew the 100th flight for the UCAS-D program. The program objectives were completed in July, which included
9964-522: The two aircraft disconnect and the receiver aircraft departs the formation. When not in use, the boom is stored flush with the bottom of the tanker's fuselage to minimize drag. In the KC-97 and KC-135 the boom operator lies prone, while the operator is seated in the KC-10 , all viewing operations through a window at the tail. The KC-46 seats two operators at the front of the aircraft viewing camera video on 3D screens. The US Air Force fixed-wing aircraft use
10070-775: The utility of the technique on 25 October 1923, when a DH-4 flew from Sumas, Washington , on the Canada–United States border , to Tijuana, Mexico , landing in San Diego , using mid-air refuelings at Eugene, Oregon , and Sacramento, California . Similar trial demonstrations of mid-air refueling technique took place at the Royal Aircraft Establishment in England and by the Armée de l'Air in France in
10176-465: The valve is retained in the tanker drogue and prevents further refueling from that drogue until removed during ground maintenance. A "buddy store" or "buddy pod" is an external pod loaded on an aircraft hardpoint that contains a hose and drogue system (HDU). Buddy stores allow fighter / bomber aircraft to be reconfigured for "buddy tanking" other aircraft. This allows an air combat force without dedicated/specialized tanker support (for instance,
10282-411: The viability of the chosen approach, or to test them on ordinary users. Technology demonstrations are often used in the computer industry, emerging as an important tool in response to short development cycles in software and hardware development. Computer technology demos should not be confused with demoscene -based demos , which, although often demonstrating new software techniques, are regarded as
10388-417: The way to showing how a business project may be justified. Large companies with tens or hundreds of Sales Engineers will often have a team who specialize in the production of demonstration systems and plans. Aerial refueling Aerial refueling ( en-us ), or aerial refuelling ( en-gb ), also referred to as air refueling , in-flight refueling ( IFR ), air-to-air refueling ( AAR ), and tanking ,
10494-470: Was eventually modified by Airspeed to Cobham's specification, for a non-stop flight from London to India , using in-flight refueling to extend the plane's flight duration. Meanwhile, in 1929, a group of US Army Air Corps fliers, led by then Major Carl Spaatz , set an endurance record of over 150 hours with a Fokker C-2A named the Question Mark over Los Angeles. Between 11 June and 4 July 1930,
10600-519: Was initially funded under a US$ 635.8 million contract awarded by the Navy in 2007. By January 2012, the X-47B's total program cost had grown to an estimated $ 813 million. Government funding for the X-47B UCAS-D program was to run out at the end of September 2013, with the close of the fiscal year . However, in June 2014 the Navy provided an additional $ 63 million for "post-demonstration" development of
10706-417: Was mainly concerned about transatlantic flights for faster postal service between Europe and America. In 1931 W. Irving Glover, the second assistant postmaster, wrote an extensive article for Popular Mechanics concerning the challenges and the need for such a regular service. In his article he even mentioned the use of aerial refueling after takeoff as a possible solution. At Le Bourget Airport near Paris,
10812-712: Was planned for November 2009, but the project fell behind schedule. On 29 December 2009, Northrop Grumman oversaw towed taxi tests of the aircraft at the Palmdale facility, with it taxiing under its own power for the first time in January 2010. The first flight of the X-47B demonstrator, designated Air Vehicle 1 (AV-1), took place at Edwards Air Force Base, California , on 4 February 2011. It first flew in cruise configuration with its landing gear retracted on 30 September 2011. A second X-47B demonstrator, designated AV-2, conducted its maiden flight at Edwards Air Force Base on 22 November 2011. The two X-47Bs were initially planned to have
10918-416: Was publicly demonstrated for the first time in 1935. In the system the receiver aircraft, at one time an Airspeed Courier , trailed a steel cable which was then grappled by a line shot from the tanker, a Handley Page Type W10 . The line was then drawn back into the tanker where the receiver's cable was connected to the refueling hose. The receiver could then haul back in its cable bringing the hose to it. Once
11024-495: Was pumped. Some historic systems used for pioneering aerial refueling used the grappling method, where the tanker aircraft unreeled the fuel hose and the receiver aircraft would grapple the hose midair, reel it in and connect it so that fuel can be transferred either with the assistance of pumps or simply by gravity feed . This was the method used on the Question Mark endurance flight in 1929. The probe-and-drogue system
11130-522: Was reported that the X-47B demonstrators would become museum exhibits upon completing flight testing. In June 2015, United States Secretary of the Navy Ray Mabus stated that the X-47B program should continue but that Northrop-Grumman should not gain an unfair advantage in the competition for the UCLASS contract. In July 2015, the Navy stated that the X-47Bs would remain in flying condition rather than being converted to museum exhibits, allowing for
11236-422: Was so successful that in June orders went out to equip all new B-50s and subsequent bombers with receiving equipment. Two dedicated air refueling units were formed on 30 June 1948: the 43d Air Refueling Squadron at Davis-Monthan Air Force Base , Arizona , and the 509th Air Refueling Squadron at Walker Air Force Base , New Mexico . The first ARS aircraft used FRL's looped-hose refueling system, but testing with
#931068