The Ryan AQM-91 Firefly was a developmental drone developed during the Vietnam War to perform long-range reconnaissance, especially into China .
112-659: The Ryan Model 147 Lightning Bug reconnaissance drone was enjoying success in Vietnam in the early 1960s, but it lacked the range to fly deep into China and back out again. In particular, the Chinese nuclear development facility at Lop Nor was far out of reach of the Lightning Bugs, and was barely within reach of the Lockheed U-2 spyplane, which had become far too vulnerable to SAMs . US intelligence thus needed
224-411: A General Electric YJ97-GE-3 turbojet providing 4,000 pounds (1,815 kg) thrust, with the engine exhaust mixed with cool air to reduce its infrared signature. The YJ97 was derived from a General Electric demonstrator engine designated the "GE1". The Model 154 was launched by a DC-130 Hercules director aircraft, and recovered in midair by helicopter. It had a precision-navigation autopilot system,
336-433: A temperature measurement of an object using an infrared imager, it is necessary to estimate or determine the object's emissivity. For quick work, a thermographer may refer to an emissivity table for a given type of object, and enter that value into the imager. The imager would then calculate the object's contact temperature based on the value entered from the table and the object's emission of infrared radiation as detected by
448-427: A thermal camera captures and creates an image of an object by using infrared radiation emitted from the object in a process, which are examples of infrared imaging science . Thermographic cameras usually detect radiation in the long- infrared range of the electromagnetic spectrum (roughly 9,000–14,000 nanometers or 9–14 μm ) and produce images of that radiation, called thermograms . Since infrared radiation
560-949: A 1280 x 720 focal plane array (FPA). Some of the materials used for the sensor arrays are amorphous silicon (a-Si), vanadium(V) oxide (VOx), lanthanum barium manganite (LBMO), lead zirconate titanate (PZT), lanthanum doped lead zirconate titanate (PLZT), lead scandium tantalate (PST), lead lanthanum titanate (PLT), lead titanate (PT), lead zinc niobate (PZN), lead strontium titanate (PSrT), barium strontium titanate (BST), barium titanate (BT), antimony sulfoiodide (SbSI), and polyvinylidene difluoride (PVDF). Some specification parameters of an infrared camera system are number of pixels , frame rate , responsivity , noise-equivalent power , noise-equivalent temperature difference (NETD), spectral band, distance-to-spot ratio (D:S), minimum focus distance, sensor lifetime, minimum resolvable temperature difference (MRTD), field of view , dynamic range , input power, and mass and volume. IR film
672-401: A Firebee with minimal changes. A US$ 1.1 million contract was issued on 2 February 1962, requesting four Firebee drones modified for aerial reconnaissance. The modified Firebees were funded from a program named " Big Safari ", established in the 1950s to fund fast-track conversions of existing aircraft for the reconnaissance mission. Big Safari would continue to work on reconnaissance drones during
784-499: A certain direction at a certain altitude for a certain time, and then turn around and return the way it came. This aircraft was intended only as a demonstrator and to evaluate the new guidance system; it carried no cameras. Three test flights were performed in April 1962 and demonstrated the validity of the concept, with the drone performing a mission which ranged from New Mexico , north into Utah , and then back again with no guidance from
896-512: A cover story, describing the drones as high-altitude targets for surface-to-air missiles (SAMs) in case one of them came down in a public area. The flights demonstrated that the modifications did not compromise the Firebee's performance. Ryan actually wanted to build a completely new drone, the Ryan Model 136 , for the reconnaissance mission. The Model 136, or Red Wagon , was optimized for
1008-429: A diplomatic effort to build ties with China, and reconnaissance overflights were cancelled. Satellite reconnaissance capabilities had improved through the 1960s, leading to the first launch of the advanced KH-9 Hexagon satellite on 15 June 1971, which provided strategic intelligence without diplomatic consequences. The Model 154 program lingered on for a few more years, but in 1973 all were put in mothballs, and scrapped
1120-702: A diverse series of variants configured for a wide array of mission-specific roles, with multiple new systems, sensors and payloads used, modified and improved upon during the operational deployment of these drones in Southeast Asia. Missions performed by the Model 147 series RPVs included high- and low- altitude photographic and electronic aerial reconnaissance, surveillance , decoy , electronic warfare , signals intelligence , and psychological warfare . The Ryan drones were designed without landing gear for simplicity and to save weight. Like its Firebee predecessor,
1232-553: A dual-camera payload synchronized to a bright white strobe light fitted into the drone's belly. The strobe lit up the sky when it went off. Both the 147NREs and 147NPs went into action in Vietnam in spring of 1967. The first 147NRE mission was in late May, with the first 147NP mission following a week later. The Model 147NREs were painted black as appropriate to their night mission, while the Model 147NPs were painted in jungle camouflage colors. The Model 147NPs performed as desired, but
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#17327827943341344-651: A fast track. The new variant was the Model 147NP , which was derived from the initial Model 147A. The Model 147NP had the older J69-T-29A engine and a 15-foot (4.6 m) wingspan, plus a fuselage stretched to 28 feet (8.5 m). While Ryan was working on the Model 147NP, the Air Force also came forward with an urgent requirement for a low-altitude night reconnaissance drone. Four Model 147NPs were pulled from production and modified as Model 147NRE s, where "NRE" stood for "night reconnaissance electronic". The Model 147NREs had
1456-408: A few years after that. Twenty-eight had been built, including 20 production models. The Model 154 had an engine on the top of the fuselage to reduce its radar cross-section and infrared signature as seen from below, as well as twin inward-canted tailfins to conceal the exhaust stream. It had a fuselage with flat bottom. A ground radar would need to be directly below the drone to detect it, but by
1568-418: A high price range (often US$ 3,000 or more) due to the expense of the larger pixel array (state of the art 1280 x 1024), while less expensive models (with pixel arrays of 40x40 up to 160x120 pixels) are also available. Fewer pixels reduce the image quality making it more difficult to distinguish proximate targets within the same field of view. There is also a difference in refresh rate. Some cameras may only have
1680-519: A highly modified Firebee intended to perform photographic and signals intelligence (SIGINT) reconnaissance from outside Soviet airspace. Lucy Lee seemed to be on track, but was then abruptly cancelled in January 1962. Just as the whole idea of reconnaissance drones seemed to be completely dead, the USAF came to rescue the program. The Air Force selected the cheapest option, a reconnaissance drone based on
1792-427: A layer of amorphous silicon , or a thin film vanadium(V) oxide sensing element suspended on silicon nitride bridge above the silicon-based scanning electronics. The electric resistance of the sensing element is measured once per frame. Current improvements of uncooled focal plane arrays (UFPA) are focused primarily on higher sensitivity and pixel density. In 2013 DARPA announced a five-micron LWIR camera that uses
1904-521: A long-range drone with a high degree of survivability. Such requirements spelled out a completely new design, not a modification of a target drone. Ryan pursued advanced drone concepts on a part-time basis. After discussions with the CIA that went nowhere, Ryan pitched their advanced reconnaissance drone concepts to the Air Force in early 1966. The USAF was interested, and opened up a design competition, with Ryan competing with North American Aviation . Ryan won
2016-461: A miniature Stirling cycle refrigerator or liquid nitrogen . Thermal images, or thermograms, are actually visual displays of the amount of infrared energy emitted, transmitted, and reflected by an object. Because there are multiple sources of the infrared energy, it is difficult to get an accurate temperature of an object using this method. A thermal imaging camera is capable of performing algorithms to interpret that data and build an image. Although
2128-545: A modern thermographic camera is often similar to a camcorder . Often the live thermogram reveals temperature variations so clearly that a photograph is not necessary for analysis. A recording module is therefore not always built-in. Specialized thermal imaging cameras use focal plane arrays (FPAs) that respond to longer wavelengths (mid- and long-wavelength infrared). The most common types are InSb , InGaAs , HgCdTe and QWIP FPA. The newest technologies use low-cost, uncooled microbolometers as FPA sensors. Their resolution
2240-462: A number of Model 147J drones were lost in development. Among the 77 missions flown by the drones in 1965 were three flights by a special SIGINT modification of the Model 147B, designated the Model 147E , another "SAM sniffer" variant. Three Model 147Es were sent to South Vietnam in October 1965 as part of a program codenamed UNITED EFFORT. The SIGINT packages failed on all three initial missions, and
2352-468: A percent. The guidance system proved to be very tricky, and first powered flight of a Model 154 did not take place until September 1968. General characteristics Performance Related development Ryan Model 147 Lightning Bug The Ryan Model 147 Lightning Bug is a jet -powered drone, or unmanned aerial vehicle , produced and developed by Ryan Aeronautical from the earlier Ryan Firebee target drone series. Beginning in 1962,
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#17327827943342464-487: A radar codenamed Fan Song and it was simple enough to pick up its signals with a normal SIGINT aircraft. The SA-2 was also radio-controlled to the target by a ground command guidance link, with the missile carrying a transponder that sent back a signal to the Fan Song radar to allow tracking. Picking up these radio command signals was hazardous, since they only came on when a missile was launched. The proximity fuze signal
2576-461: A reconnaissance payload, a self-destruct system to ensure that none of its sensitive gear fell into enemy hands, and was to carry electronic countermeasures to further improve its survivability. The primary reconnaissance payload was an Itek KA-80A Optical Bar Camera , but in principle it could also carry thermographic camera or a SIGINT payload. The guidance system was designed to provide navigation accuracies with an error of no more than half
2688-461: A rice paddy. The drone, however was dragged over the ground by the parachute which badly damaged the machine. Its film payload was recovered intact and although the drone's navigation hadn't been as accurate as hoped, images of several primary targets were recovered. A total of five Lightning Bug missions were performed over China into early September 1964, with only two of them successful. The Nationalist Chinese , however were very enthusiastic about
2800-453: A series of mathematical algorithms. Since the camera is only able to see the electromagnetic radiation that is impossible to detect with the human eye , it will build a picture in the viewer and record a visible picture, usually in a JPG format. In order to perform the role of non-contact temperature recorder, the camera will change the temperature of the object being viewed with its emissivity setting. Other algorithms can be used to affect
2912-427: A side-to-side scan camera and a new paint job. The high-altitude Lightning Bugs had been painted black which is a high-visibility color at low altitude. Model 147Js were painted gray on top and white underneath. The fast-moving 147J drones flew low, making them difficult targets and increasing their odds of returning from a mission. Up to then the drones had parachuted to the ground upon return, but were often damaged by
3024-473: A small antenna fairing on top of the fin and ability to carry chaff dispensers and active jamming pods. While they were a good asset to USAF capabilities during Operation Rolling Thunder , these medium-altitude Combat Angel ECM RPVs saw little use after the November 1968 official halt to air strikes on North Vietnam. The Model 147NC , which entered service in 1969 with the 11th Tactical Drone Squadron
3136-429: A statement that the aircraft was a "high altitude target". Test flights were halted for a few weeks while procedures were reviewed. Flights were resumed, culminating in long-range evaluations in late 1971. Testing concluded with the Model 154 exceeding its altitude requirements and proving almost invisible to radar. However, by this time the need for the Model 154 had vanished. In July 1971, President Richard Nixon began
3248-502: A thermal imaging camera. Emitted radiant power is generally what is intended to be measured; transmitted radiant power is the radiant power that passes through the subject from a remote thermal source, and; reflected radiant power is the amount of radiant power that reflects off the surface of the object from a remote thermal source. This phenomenon occurs everywhere, all the time. It is a process known as radiant heat exchange, since radiant power × time equals radiant energy . However, in
3360-654: A total of 20 reconnaissance drone flights in 1964. The flights were controlled by the Strategic Air Command (SAC) from Monkey Mountain Facility in South Vietnam. The controller was stationed at Bien Hoa and the support staff was located at Da Nang Air Base , consisting of two SAC Single Sideband Operators, SSgt Willie V Collier nicknamed "Willie VC" and SSgt Walter J Dawson from the 46th Comm Gp Barksdale AFB . The Chinese were extremely eager to shoot
3472-702: A wide range of narrow gap semiconductors including indium antimonide (3-5 μm), indium arsenide , mercury cadmium telluride (MCT) (1-2 μm, 3-5 μm, 8-12 μm), lead sulfide , and lead selenide . Infrared photodetectors can be created with structures of high bandgap semiconductors such as in quantum well infrared photodetectors . A number of superconducting and non-superconducting cooled bolometer technologies exist. In principle, superconducting tunneling junction devices could be used as infrared sensors because of their very narrow gap. Small arrays have been demonstrated. They have not been broadly adopted for use because their high sensitivity requires careful shielding from
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3584-451: A wingspan extended to 15 feet (4.6 m), and incorporated the no-contrail system. Three of this batch of Model 147Cs were modified to become special-purpose Model 147D s. The 147D combined the functions of reconnaissance and the original Firebee mission of aerial target: it was to be used as bait for SA-2 SAMs to obtain data on signals associated with the SA-2. The SAM was targeted by
3696-416: Is a device that creates an image using infrared (IR) radiation, similar to a normal camera that forms an image using visible light . Instead of the 400–700 nanometre (nm) range of the visible light camera, infrared cameras are sensitive to wavelengths from about 1,000 nm (1 micrometre or μm) to about 14,000 nm (14 μm). The practice of capturing and analyzing the data they provide
3808-596: Is a term that is often misunderstood and misused. It represents a material's ability to emit thermal radiation and is an optical property of matter . Each material has a different emissivity, which may vary by temperature and infrared wavelength. For example, clean metal surfaces have emissivity that decreases at longer wavelengths; many dielectric materials, such as quartz (SiO 2 ), sapphire (Al 2 O 3 ), calcium fluoride (CaF 2 ), etc. have emissivity that increases at longer wavelength; simple oxides, such as iron oxide (Fe 2 O 3 ) display relatively flat emissivity in
3920-498: Is able to find deterioration, i.e., higher temperature components prior to their failure. It can be used to measure or observe in areas inaccessible or hazardous for other methods. It is a non-destructive test method. It can be used to find defects in shafts, pipes, and other metal or plastic parts. It can be used to detect objects in dark areas. It has some medical application, essentially in physiotherapy . There are various cameras cheaper and more expensive. Quality cameras often have
4032-402: Is both energy-intensive and time-consuming. The camera may need several minutes to cool down before it can begin working. The most commonly used cooling systems are peltier coolers which, although inefficient and limited in cooling capacity, are relatively simple and compact. To obtain better image quality or for imaging low temperature objects Stirling engine cryocoolers are needed. Although
4144-465: Is called thermography . Thermographic cameras can be broadly divided into two types: those with cooled infrared image detectors and those with uncooled detectors. Cooled detectors are typically contained in a vacuum-sealed case or Dewar and cryogenically cooled. The cooling is necessary for the operation of the semiconductor materials used. Typical operating temperatures range from 4 K (−269 °C) to just below room temperature, depending on
4256-420: Is considerably lower than that of optical cameras, mostly 160x120 or 320x240 pixels , up to 1280 x 1024 for the most expensive models. Thermal imaging cameras are much more expensive than their visible-spectrum counterparts, and higher-end models are often export-restricted due to the military uses for this technology. Older bolometers or more sensitive models such as InSb require cryogenic cooling, usually by
4368-408: Is due to differences in their fabrication processes, limited by currently available technology. An uncooled thermal camera also needs to deal with its own heat signature. Uncooled detectors are mostly based on pyroelectric and ferroelectric materials or microbolometer technology. The material are used to form pixels with highly temperature-dependent properties, which are thermally insulated from
4480-521: Is emitted by all objects with a temperature above absolute zero according to the black body radiation law , thermography makes it possible to see one's environment with or without visible illumination. The amount of radiation emitted by an object increases with temperature; therefore, thermography allows one to see variations in temperature. When viewed through a thermal imaging camera, warm objects stand out well against cooler backgrounds; humans and other warm-blooded animals become easily visible against
4592-411: Is sensitive to infrared (IR) radiation in the 250 to 500 °C (482 to 932 °F) range, while the range of thermography is approximately −50 to 2,000 °C (−58 to 3,632 °F). So, for an IR film to work thermographically, the measured object must be over 250 °C (482 °F) or be reflecting infrared radiation from something that is at least that hot. Night vision infrared devices image in
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4704-424: Is to use an infrared vision device, usually a focal plane array (FPA) infrared camera capable of detecting radiation in the mid (3 to 5 μm) and long (7 to 14 μm) wave infrared bands, denoted as MWIR and LWIR, corresponding to two of the high transmittance infrared windows . Abnormal temperature profiles at the surface of an object are an indication of a potential problem. In passive thermography ,
4816-462: Is to use gases bottled at high pressure, nitrogen being a common choice. The pressurised gas is expanded via a micro-sized orifice and passed over a miniature heat exchanger resulting in regenerative cooling via the Joule–Thomson effect . For such systems the supply of pressurized gas is a logistical concern for field use. Materials used for cooled infrared detection include photodetectors based on
4928-544: The FDA warning that "those who opt for this method instead of mammography may miss the chance to detect cancer at its earliest stage". Government and airport personnel used thermography to detect suspected swine flu cases during the 2009 pandemic. Thermography has a long history, although its use has increased dramatically with the commercial and industrial applications of the past fifty years. Firefighters use thermography to see through smoke , to find persons, and to localize
5040-576: The Soviet Union after launch from the Barents Sea , with recovery in Turkey . The Firebee has a low radar cross-section , making it hard to detect. With lengthened wings, the drone would also be able to fly at high altitude, further increasing its elusiveness. It could be launched by a Lockheed DC-130 , or JATO -boosted from a land site or ship . Ryan presented its report on the studies to
5152-496: The imperialist United States ." Although self-destruct charges were considered for installation on overflight Lightning Bugs it was finally decided not to, and the United States simply adopted a policy of "no comment" when asked about the reconnaissance drones. With no American crews lost in the shoot-downs, the U.S. press paid very little attention to the Chinese reports. The Air Force had enthusiastically embraced
5264-440: The 147E and 147F SIGINT missions and the 147N and 147NX decoys . One of the 147Js actually took a picture of an SA-2 SAM streaking past it. The Air Force was very pleased with the low-altitude Model 147J and feared there would not be enough of them to keep up with operational attrition. Some Model 147Gs were modified to the 147J configuration, but the USAF also asked Ryan to come up with a new low-altitude reconnaissance drone on
5376-445: The 147NC was not deployed in its intended role. When bombing resumed in 1972, chaff was dropped by piloted F-4 Phantom fighters instead. Model 147NCs did get into action during the "political offensive" of 1972 by dropping propaganda leaflets . The project was codenamed Litterbug, but the troops called them "bullshit bombers". A medium altitude training version of the 147NC designated the Model 147NC(M1) lacked underwing pylons and
5488-430: The 1990s did substantial interest, organization and funding again emerge from the U.S. Air Force and intelligence agencies to develop, acquire and widely deploy combat UAVs. In 1959, Ryan Aeronautical performed a study to investigate how the company's Firebee target drone could be used for long-range reconnaissance missions. Ryan engineers concluded they could increase the Firebee's range to allow it to fly south over
5600-535: The Air Force awarded Ryan a US$ 200,000 contract to perform further studies. Ryan conducted radar measurements on sub-scale Firebee models and determined that their radar signature could be reduced by placing a wire screen over the jet intake, painting parts of the drone with non-conductive paint, and placing radar-absorbent material pads on both sides of the fuselage. Test flights of the modified Firebees were performed in September and October 1961. Flights were given
5712-487: The Fan Song radar. The AN/ALQ-51 was a deception jammer, meaning it manipulated radar signals to mislead the targeting radar into thinking the target was somewhere other than its actual location. Since the Americans had not actually acquired a Fan Song at the time, the box had been tested against a radar simulating a Fan Song. The jammer worked well in tests, but fielding it without sending it up against an actual enemy radar
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#17327827943345824-537: The Lightning Bug and was trying to refine the type, working with Ryan to obtain an improved version of the high-altitude Model 147B, designated the Model 147G . The Model 147G featured a more powerful Continental J69-T-41A turbojet, with 1,920 pounds of thrust (871 kgp), replacing the J69-T-29A used in its predecessors, and a fuselage stretched to 29 feet (8.8 m), to accommodate more fuel. The no-con system
5936-569: The Lightning Bugs to monitor Chinese activities. The drones were sent with their DC-130 director aircraft to Kadena Air Base on Okinawa to conduct overflights of southern China . The first Lightning Bug mission took place on 20 August 1964, though there were problems. The DC-130 controlling the mission was loaded with a pair of Model 147Bs. One drone failed to launch, and was later lost when it fell off its underwing pylon. The second 147B successfully completed its mission over China, flew back to Taiwan , deployed its parachute and splashed down in
6048-653: The Lightning Bugs. They had been flying U-2 spy planes over mainland China on behalf of the Central Intelligence Agency and were experiencing increased losses from SA-2 SAMs . To expand reconnaissance flights to North Vietnam , in early October 1964 these operations were shifted to Bien Hoa Air Base in South Vietnam . The first Lightning Bug mission flown from Bien Hoa took place on 11 October 1964. Increasing numbers of Model 147B missions were flown over North Vietnam and southern China, with
6160-451: The Model 147 could either be air-launched from a larger carrier aircraft or launched from the ground using a solid rocket booster; at completion of its mission the drone deployed its own recovery parachute which could be snatched in mid-air by a recovery helicopter (in a combat environment it was naturally not desired to recover the drone on, from or near enemy territory and ground or water impact could also cause damage to or loss of
6272-417: The Model 147 was introduced as a reconnaissance RPV (Remotely Piloted Vehicle, nomenclature of that era) for a United States Air Force project named Fire Fly. Over the next decade – assisted with secret funding from the recently formed National Reconnaissance Office along with support of the Strategic Air Command and Ryan Aeronautical's own resources – the basic Model 147 design would be developed into
6384-486: The Model 147Es were sent back to the U.S. for environmental tests to track down the problem; it turned out that the SIGINT package failed when overheated. The problem was corrected and the Model 147Es were sent back to the combat zone. On 13 February 1966 — the fourth Model 147E mission — the drone was destroyed by an SA-2, but not before it relayed the vital signal data. The U.S. had been desperate to get this data ever since
6496-436: The Model 147NREs did not quite meet expectations. The "footprint" of the strobe light was fairly small, and the drone's navigation system lacked the accuracy to put the cameras precisely on target. Despite these drawbacks the Air Force did obtain useful intelligence from the drone's cameras even when they were not on target, as well as some minor psychological warfare effect from the startling bright strobe flashes, and felt that
6608-504: The U.S. Air Force in mid-April 1960. On 1 May 1960 an American Lockheed U-2 spy plane was shot down over the USSR and its pilot, Francis Gary Powers , captured. On 1 July a Boeing RB-47H reconnaissance aircraft flying an electronic intelligence mission in international airspace near the Soviet border was shot down; four of its crew were killed and the other two captured. A few days later,
6720-527: The Vietnam War, and would also assist UAV programs in later wars. The new reconnaissance drones were designated Model 147A and codenamed Fire Fly . Specifications dictated a 1,200 miles (1,900 kilometres) range and a cruise altitude of 55,000 feet (17 km). The first Model 147A was a standard Firebee with a new guidance system consisting of no more than a timer-programmer, a gyrocompass , and an altimeter . The Fire Fly could be programmed to fly in
6832-478: The background radiation. Superconducting detectors offer extreme sensitivity, with some able to register individual photons. For example, ESA 's Superconducting camera (SCAM) . However, they are not in regular use outside of scientific research. Uncooled thermal cameras use a sensor operating at ambient temperature, or a sensor stabilized at a temperature close to ambient using small temperature control elements. Modern uncooled detectors all use sensors that work by
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#17327827943346944-401: The base of a fire. Maintenance technicians use thermography to locate overheating joints and sections of power lines , which are a sign of impending failure. Building construction technicians can see thermal signatures that indicate heat leaks in faulty thermal insulation and can use the results to improve the efficiency of heating and air-conditioning units. The appearance and operation of
7056-478: The case of infrared thermography, the above equation is used to describe the radiant power within the spectral wavelength passband of the thermal imaging camera in use. The radiant heat exchange requirements described in the equation apply equally at every wavelength in the electromagnetic spectrum . If the object is radiating at a higher temperature than its surroundings, then power transfer will be taking place and power will be radiating from warm to cold following
7168-544: The change of resistance , voltage or current when heated by infrared radiation. These changes are then measured and compared to the values at the operating temperature of the sensor. Uncooled infrared sensors can be stabilized to an operating temperature to reduce image noise, but they are not cooled to low temperatures and do not require bulky, expensive, energy consuming cryogenic coolers. This makes infrared cameras smaller and less costly. However, their resolution and image quality tend to be lower than cooled detectors. This
7280-559: The chlorosulfonic acid was very corrosive which required use of high-grade stainless steel plumbing. During the Cuban Missile Crisis a U-2 was shot down over Cuba on 27 October 1962 by an SA-2 and its pilot killed. Afterwards the Model 147As were authorized for reconnaissance missions in place of the U-2. The drones were mounted under the wings of their DC-130 Hercules controller aircraft, its propellers turning, at ready on
7392-480: The competition in June 1966, and the new design was designated the "Model 154 / AQM-91A Firefly". The basic design concept resembled that of the Model 136 Red Wagon drone that Ryan had proposed earlier in the decade, but which had been turned down in favor of a modified Firebees . The name "Firefly" was resurrected from the early Model 147 program for the new drone, though it was also referred to as " Compass Arrow " after
7504-464: The concept was worth further development. Another low-altitude reconnaissance variant was derived from the Model 147NP, the Model 147NQ . Its main distinction: instead of using an automatic guidance system, it was radio-controlled by a crewman on its DC-130 launch aircraft. The Model 147NA was a medium-altitude electronic warfare Lightning Bug variant developed under the USAF's Compass Bin and Combat Angel programs. The 147NA had extended-span wings,
7616-417: The contact temperature of a thermally uniform black body radiator were 50 °C (122 °F), the black body would emit thermal radiation characteristic of 50 °C (122 °F). An ordinary object emits less infrared radiation than a theoretical black body. The fraction of its actual emission to the theoretical emission (of the black body) is its emissivity (or emissivity coefficient). In order to make
7728-453: The cooling apparatus may be comparatively bulky and expensive, cooled infrared cameras provide greatly superior image quality compared to uncooled ones, particularly of objects near or below room temperature. Additionally, the greater sensitivity of cooled cameras also allow the use of higher F-number lenses, making high performance long focal length lenses both smaller and cheaper for cooled detectors. An alternative to Stirling engine coolers
7840-558: The deployment of the SA-2, and officials claimed that this single flight justified the entire Model 147 program. The information was immediately put to use to develop a simple warning system that would tell the pilot when an SA-2 command signal was turned on, meaning a missile launch was imminent; this device would go into production as the AN/APR-26. Another countermeasure, the AN/ALQ-51 "Shoe Horn", had been developed to help deal with
7952-532: The destroyer USS Maddox was sailing in international waters off the North Vietnamese coast when it was allegedly attacked by three North Vietnamese PT boats in what is known as the Gulf of Tonkin incident , which became a pretext for a major expansion of U.S. involvement in the war in Vietnam . The Johnson Administration feared Communist Chinese intervention in the widening war, and decided to use
8064-472: The detector technology. Most modern cooled detectors operate in the 60 Kelvin (K) to 100 K range (-213 to -173 °C), depending on type and performance level. Without cooling, these sensors (which detect and convert light in much the same way as common digital cameras, but are made of different materials) would be 'blinded' or flooded by their own radiation. The drawbacks of cooled infrared cameras are that they are expensive both to produce and to run. Cooling
8176-511: The drone or its payload). At the end of the Vietnam War in 1975 the U.S. military 's available funding and need for combat drones severely declined, even as Teledyne Ryan introduced further advanced developments of the Model 147 series such as the BGM-34 strike and defense suppression RPVs. Costs of maintaining the Lightning Bugs at full readiness could no longer be justified. Only by
8288-538: The drone out to sea, and other fighters were lost due to "friendly fire" accidents while hunting the drones. The decoys worked so well that the Air Force ordered another batch of ten with a few minor improvements, and designated them Model 147NX . The initial Model 147Ns had been programmed to turn back and head for home in order to simulate a normal operational drone flight profile, and a few of them surprisingly did make it back even with their limited fuel supply. They crashed since they were not designed to be recovered, but
8400-422: The drones down and managed to destroy one on November 15, 1964. Lightning Bug overflights continued and so did Chinese efforts to intercept them. The Chinese succeeded in destroying five drones by mid-April, and on 20 April 1965 put the wrecks of three of them on public display. With every shoot-down, the Chinese issued verbose press reports praising China's "great victory" in shooting down "reconnaissance planes of
8512-521: The environment and read electronically. Ferroelectric detectors operate close to phase transition temperature of the sensor material; the pixel temperature is read as the highly temperature-dependent polarization charge. The achieved NETD of ferroelectric detectors with f/1 optics and 320x240 sensors is 70-80 mK. A possible sensor assembly consists of barium strontium titanate bump-bonded by polyimide thermally insulated connection. Silicon microbolometers can reach NETD down to 20 mK. They consist of
8624-445: The environment, day or night. As a result, thermography is particularly useful to the military and other users of surveillance cameras. Some physiological changes in human beings and other warm-blooded animals can also be monitored with thermal imaging during clinical diagnostics. Thermography is used in allergy detection and veterinary medicine . Some alternative medicine practitioners promote its use for breast screening , despite
8736-433: The features of interest are naturally at a higher or lower temperature than the background. Passive thermography has many applications such as surveillance of people on a scene and medical diagnosis (specifically thermology ). In active thermography , an energy source is required to produce a thermal contrast between the feature of interest and the background. The active approach is necessary in many cases given that
8848-414: The first mission performed by one alongside a Model 147G on March 3, 1966. The two drones followed a parallel path until they reached the target area, where they diverged. North Vietnamese air defenses tracked the "brighter" 147N instead of the 147G, which was recovered. As an added bonus the 147Ns resulted in a few "kills" of North Vietnamese fighter aircraft. One fighter ran out of fuel when the pilot chased
8960-432: The ground (though accompanied by a B-57 chase plane ). The second Model 147A had an 35-inch (89 cm) "plug" inserted into the fuselage to carry an additional 68 US gallons (258 litres) of fuel, increasing overall length from 22 feet (6.71 m) to 25 feet 9 inches (7.85 m). It also had a new nose containing a camera from the U-2. After four successful test flights performed in April and early May 1962,
9072-415: The image shows the viewer an approximation of the temperature at which the object is operating, the camera is actually using multiple sources of data based on the areas surrounding the object to determine that value rather than detecting the actual temperature. This phenomenon may become clearer upon consideration of the formula: where incident radiant power is the radiant power profile when viewed through
9184-426: The imager. In order to get a more accurate temperature measurement, a thermographer may apply a standard material of known, high emissivity to the surface of the object. The standard material might be as complex as industrial emissivity spray produced specifically for the purpose, or as simple as standard black insulation tape , with an emissivity of about 0.97. The object's known temperature can then be measured using
9296-441: The impact. The Air Force then devised a retrieval method using a Sikorsky CH-3E helicopter that snagged the parachute in mid-air and winched it in. Mid-air retrieval proved effective, with an eventual 2,655 successful recoveries in 2,745 attempts, a 97% recovery rate. A total of 105 drone missions were flown over North Vietnam and Communist China in 1966. Most of these were 147G flights, along with some 147Js, as well as
9408-520: The infrared spectrum. A material's emissivity can range from a theoretical 0.00 (completely not-emitting) to an equally theoretical 1.00 (completely emitting). An example of a substance with low emissivity would be silver, with an emissivity coefficient of .02. An example of a substance with high emissivity would be asphalt, with an emissivity coefficient of .98. A black body is a theoretical object with an emissivity of 1 that radiates thermal radiation characteristic of its contact temperature. That is, if
9520-445: The inspected parts are usually in equilibrium with the surroundings. Given the super-linearities of the black-body radiation , active thermography can also be used to enhance the resolution of imaging systems beyond their diffraction limit or to achieve super-resolution microscopy . Thermography shows a visual picture so temperatures over a large area can be compared. It is capable of catching moving targets in real time. It
9632-400: The meantime, so the new drones were given the codename Lightning Bug . In July 1963, the Lightning Bugs reached full operational status, though they had yet to fly an operational mission. In late December 1963, the Air Force ordered fourteen more Model 147Bs. By this time Fidel Castro was threatening to shoot down U-2s flying over Cuba , and a May 1964 study concluded that the Lightning Bug
9744-404: The measurement, including the transmission ability of the transmitting medium (usually air) and the temperature of that transmitting medium. All these settings will affect the ultimate output for the temperature of the object being viewed. This functionality makes the thermal imaging camera an excellent tool for the maintenance of electrical and mechanical systems in industry and commerce. By using
9856-503: The near-infrared, just beyond the visual spectrum, and can see emitted or reflected near-infrared in complete visual darkness. However, again, these are not usually used for thermography due to the high temperature requirements, but are instead used with active near-IR sources. Starlight-type night vision devices generally only magnify ambient light . All objects above the absolute zero temperature (0 K ) emit infrared radiation . Hence, an excellent way to measure thermal variations
9968-522: The next decade. Ryan Aeronautical 's engineering expertise and feedback from the USAF's operational experience with the drones would also cause them be continually modified, redesigned and optimized for better performance, and further developed to take on an array of new missions. During this time operational deployment of Model 147 drones would be undertaken by the Air Force's Strategic Air Command and its reconnaissance wings, equipped with DC-130 launch aircraft and recovery helicopters. Continued behind
10080-471: The principle stated in the second law of thermodynamics . So if there is a cool area in the thermogram, that object will be absorbing the radiation emitted by the warm object. The ability of objects to emit is called emissivity , to absorb radiation is called absorptivity . Under outdoor environments, convective cooling from wind may also need to be considered when trying to get an accurate temperature reading. The thermal imaging camera would next employ
10192-520: The program name. The test flights were conducted over the US Southwest. The project was highly secret, but on 4 August 1969 one of the prototypes failed and parachuted to ground inside the Los Alamos nuclear research complex during lunch hour. Unfortunately, it didn't land in a restricted area, and local newspeople were able to take and publish photographs of the aircraft. The Air Force released
10304-481: The proper camera settings and by being careful when capturing the image, electrical systems can be scanned and problems can be found. Faults with steam traps in steam heating systems are easy to locate. In the energy savings area, the thermal imaging camera can do more. Because it can see the effective radiation temperature of an object as well as what that object is radiating towards, it can help locate sources of thermal leaks and overheated regions as well. Emissivity
10416-405: The recovery system was not expensive and so the Model 147NX was fitted with recovery parachutes and gear as well as a cheap camera. If the decoy survived the mission, it might provide useful intelligence. By March 1966 the low-altitude Model 147J was ready for operational service; it featured a "barometric altitude control system" (BLACS), a dual camera payload featuring a front-to-back scan camera,
10528-452: The role with long straight wings for high-altitude flight, an engine set on the back of the fuselage to reduce its radar and infrared signatures as seen from below, and inward-canted twin tail fins to conceal the exhaust plume. The project stalled, however as the incoming Kennedy Administration was certain to reassess many military projects and Red Wagon was put on hold. Ryan then proposed another drone project named "Lucy Lee" consisting of
10640-580: The runway when notification came from Air Force Chief of Staff Curtis LeMay that the mission was scrubbed. The U-2s were used for reconnaissance over Cuba instead, with missions resuming on 5 November 1962. LeMay wanted to reserve the Fire Fly for later. Although the Fire Fly had yet to be used operationally, the Air Force was enthusiastic enough about the concept to issue contracts for follow-on variants. The USAF ordered nine Model 147B s, including two prototypes and seven production aircraft. The Model 147B
10752-594: The scenes support from the National Reconnaissance Office , which had allocated project funds from its outset via the classified Program D for developing airborne intelligence collection platforms, also ensured that the Lightning Bug project would grow into a full-fledged aerial reconnaissance program. The Lightning Bugs remained a potentially valuable reconnaissance asset. The first opportunity for operational use came in August 1964. On 2 August,
10864-494: The skies were mostly overcast, and even in fair weather smoke or ground haze could obscure reconnaissance targets. For this reason, the Air Force decided to develop a low-altitude version of the Lightning Bug. In October 1965, the service issued a contract to Ryan to develop the Model 147J , a fast-track modification of the Model 147G with a low-altitude navigation system. Low-altitude flight was more demanding than high-altitude flight, since there were many more things to run into, and
10976-530: The standard emissivity. If desired, the object's actual emissivity (on a part of the object that is not covered by the standard material) can then be determined by adjusting the imager's setting to the known temperature. There are situations, however, when such an emissivity test is not possible due to dangerous or inaccessible conditions. In these situations, the thermographer must rely on tables. A thermographic camera (also called an infrared camera or thermal imaging camera , thermal camera or thermal imager )
11088-459: The third and fourth Model 147As (which were almost identical to the second example) were declared operational and deployed at Holloman Air Force Base in New Mexico with a Lockheed DC-130 Hercules launch aircraft. Tests conducted that summer showed the drone was almost invisible to ground radar , and interceptors that were scrambled to find it ended up chasing each other. The only problem
11200-402: The time it is detected, the aircraft is travelling away, which makes tracking difficult. The sides of the fuselage are sloped flat to deflect radar signals. It was built using a high percentage of plastic composite materials , which had a lower radar reflectivity than metal. The leading and trailing edges of the wings had inset triangles of a radar-absorbent material . The aircraft was powered by
11312-495: Was also installed. The first 147G was delivered to the USAF in July 1965. By this time U-2 overflights of defended airspace had been phased out, with that mission left to the Lightning Bugs. The Model 147G performed its first mission in October 1965, and the Model 147B flew its last mission that December. High-altitude reconnaissance over North Vietnam proved somewhat impractical. During the monsoon season, from November through March,
11424-409: Was capable of reaching 65,000 feet (20 km) altitudes and had a new camera payload that provided both greater area coverage and finer resolution. " Stealthy " features that had been built into the original Lightning Bugs were becoming less and less effective, so the Model 147H was designed with new features to improve survivability, including a radar warning receiver (RWR) to alert the drone if it
11536-426: Was designed for high-altitude reconnaissance, with wingspan extended from the 13 feet (4.0 m) span of the Model 147A to 27 feet (8.2 m), raising the 147B's operational ceiling to 62,500 feet (19.1 km). The delivery schedule for the high-altitude Model 147B was several months out, so the Air Force also ordered seven Model 147C s, a production version of the 147A, as an interim solution. The Model 147C had
11648-540: Was generally similar to the Model 147NA, with the addition of endplate auxiliary fins on its tailplane . It had been designed a few years earlier to fly at medium altitude carrying AN/ALE-2 chaff dispensers under each wing to counter enemy radar systems. The Model 147NC had originally been intended to support bombing raids over North Vietnam under Compass Bin and Combat Angel, but air strikes on North Vietnam were scaled back in March 1968 and stopped completely by November so
11760-526: Was illuminated by fighter or SAM radars, an improved guidance system that sent it into a right turn when alerted by the RWR, an ECM box named "Rivet Bouncer" to jam the SA-2 Fan Song radar, a coating in the jet intake to reduce radar reflectivity, and an improved no-contrail system. Thermographic camera Infrared thermography ( IRT ), thermal video or thermal imaging , is a process where
11872-400: Was operated for reconnaissance RPV training with the 11th Tactical Drone Squadron . Some of these were later updated to AQM-34V ( Ryan Model 255 ) standard in the mid-1970s. Despite the Air Force's attention to the low-altitude mission, the service hadn't given up on using Lightning Bugs for high-altitude reconnaissance and in fact continued to improve the high-altitude variants. The result
11984-508: Was out of the question. The Model 147 was then used to operationally test the AN/ALQ-51. A single Model 147B was fitted with the package and redesignated Model 147F , flying a number of missions in July 1966. It was finally lost after almost a dozen SA-2s had been fired at it. A primary virtue of the Lightning Bugs was that they were far more expendable than piloted reconnaissance aircraft; but by early 1966 an average of four out of five Lightning Bugs failed to return from missions. This loss rate
12096-409: Was that the drone generated a contrail , which gave it away. A "no-con" (no-contrail) program was initiated to fix the problem in subsequent variants, though apparently it wasn't fitted to the Model 147A. The system injected chlorosulfonic acid into the engine tailpipe when the drone entered hostile territory, creating tiny ice crystals which formed a transparent contrail. An effective system, although
12208-499: Was the Model 147H third-generation high-altitude Lightning Bug which made its first operational flight in March 1967 after two years of development. It was better optimized for its mission than earlier Model 147s, many of which had been modified and put into service as quickly as possible. The Model 147H had the more powerful J69-T-41A engine of the Model 147G, a lighter airframe, and a wing further stretched to 32 feet (9.8 m) span with internal fuel tanks to increase range. The 147H
12320-610: Was the best alternative. After information about the proposal leaked to the press, the U.S. administration decided to back up the U-2s with the Lockheed A-12 , precursor of the SR-71 Blackbird spy plane. While the fledgling Ryan Model 147 drones had thus far played only backstage roles, U.S. relations with China and North Korea and events in Southeast Asia would significantly ramp up their operational involvement in
12432-572: Was the most dangerous because it would only be detected moments before the SAM detonated. A special "SAM sniffer" Radar MASINT payload was installed on the Fire Fly to pick up these signals, with the drone relaying the data to an ERB-47H electronic warfare aircraft. An active radar enhancement device was installed to encourage the enemy to take shots at the drone. The three Model 147Ds were delivered in December 1962. The Fire Fly code name had leaked in
12544-453: Was unacceptable even for a relatively cheap drone, and the Air Force asked Ryan to quickly convert ten standard Firebee target drones to expendable decoys . They were fitted with traveling-wave tube (TWT) active radar enhancement devices to make them look like a bigger aircraft on radar. There were no provisions for recovery or long-range fuel capacity, since their missions were to be one-way only. The decoys were designated Model 147N , with
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