The Evolution Of Stealth Technology

On January 17, 1991, at 2:30 a.m. m., the initial attack of Operation Desert Storm was launched, the objective of which was to paralyze the Iraqi commander, control the tomahawk aboard a ship, and launch AGM-86 B-52 cruise missiles to infiltrate targets within Baghdad along with this initial attack. The emergence of deep strike assets was a new class of weapon. This attack was the first public debut of a

stealth

aircraft that took on one of the largest air defense networks in the region. The iconic Lockheed F-117 Nighthawk. The first

stealth

attack platform was among the first raids to enter Baghdad's heavily defended airspace, supported by EF-111 electronic jamming aircraft and without radar weapons, missiles or defensive countermeasures, it relied completely on its ability to remain hidden from the public. radar to penetrate Baghdad and launch its two 2,000-pound laser-guided missiles. bombs and sorties with impunity The success of these initial attacks, along with the punching of a hole in Iraq's early warning air defenses by Apache attack helicopters paved the way for a massive bombing effort over the next 24 hours composed for more than 2,600 raids aimed at command and control. bunkers missile launch platforms equipment storage areas communication facilities and airfields that night the need for stealth was demonstrated, consolidating itself on the list of essential capabilities of any new aircraft program, but where did this peculiar classified aircraft come from and what technologies Did they make it so stealthy?

It all started in the 1960s with a Soviet physicist and his underrated equations. To understand how stealth

technology

came about, we need to quantify what stealth is. Stealth is not a specific

technology

but rather a design mantra that incorporates low observability and the ability to detect. an aircraft can range from simple visual and acoustic detection to more sophisticated means such as infrared and radar emitted radiation detection and tracking a crash the potential threats faced by fighter aircraft radar detection and tracking represent the greatest risk on which optical and infrared radar detection is based is based on the bouncing of electromagnetic radiation off an object to collect information from it, however, radar differs in that the source of the reflected radiation is actively emitted by the observer with passive detection methods, the target's own emissions or ambient light are used. emit radiation to a volume of space and analyze the resulting reflected energy to detect and track apart the radiation source, the wavelength of the radiation differs between detection methods visible light has a wavelength range of 380 nanometers for violet light up to 700 nanometers for red light, infrared light occupies the wavelength range below between 700 nanometers and 1 millimeter below this is the realm of radar, the region of the spectrum known as microwaves and then the radius ranging from one millimeter to 3 meters while detecting an aircraft. a warning to defend against it must be tracked tracking is the determination of the target's position, speed and course from a reflected signal attracting aircraft is, in fact, targeting of missiles and anti-aircraft artillery smaller wavelengths allow obtain more resolvable details, making tracking easier but this is compromised by range as a general rule, the shorter the wavelength, the greater the atmospheric absorption and wave attenuation, while some air defense weapons can Optically Tracking Infrared tracking is the predominant method for closed air defense due to its ability to see an aircraft's heat through the atmosphere.

Infrared tracking works by using a camera-like infrared sensor to search the highly contrasting signature of hot aircraft exhaust gases and the hot body of the aircraft with the ambient air temperature due to atmospheric absorption. Infrared radiation can only be used to track over short distances, typically 20 miles or less. Infrared homing weapons are usually found on short-range anti-aromatics. In contrast, the longer wavelengths of radar detection and tracking are what make it so powerful than its ability to penetrate the atmosphere at much greater distances. The first military use of radar began around the beginning of World War II.

One of the most notable uses was in the air defense of England in 1939. A chain of radar stations protected the east and south coasts providing early warning to incoming aircraft. This first radar operated. on the longer wavelengths of radio and offered very basic information about incoming contacts that same year, a breakthrough in research resulted in the invention of the resonant cavity magnetron, which enabled the generation of microwave radiation of long shorter wave with large amounts of power. More details can now be obtained. assess targets such as altitude and heading speed, practical tracking radar was now possible fast forward to today and most airborne military radars, including those found, and based anti-aircraft missiles In radar they operate in the microwave wavelength range of 5 centimeters to one centimeter, as it provides a good compromise between the resolution of the range and the size of the antenna at these wavelengths it is possible to perform monitoring at distances of approximately 50 to 80 miles.

It should be noted that wavelengths from 5 centimeters to 30 centimeters are also used in ground-based early warning radars that can track targets. up to 250 miles away with proper radar tracking a firing solution can be determined with only evasion of electronic interference and the distribution of cloudy radar known as chaff which offers any form of defense because the missiles are effectively guided Rockets have limited amounts of energy available to them to maneuver if the target can exhaust this energy before it is within range of that nation or obstruct the missile's ability to maintain radar tracking the missile can be defeated this is known as going on the defensive in air combat The goal of radar stealth is to mask and have aircraft detected, tracked and fired upon from a distance, this is known as beyond visual range engagement as close ranges can transition to an infrared based attack either at low altitude or between adversary aircraft within an aerial combat, while radar energy from airborne defenses can be detected.

Infrared-guided missiles are particularly dangerous to fighter jets because they offer no warning of being tracked. The only indicator of an infrared-guided missile launch is through visual identification, although newer fighters, such as the F-35, employ external sensors that attempt to detect launches to defend against infrared missiles involve a combination of maneuvers. evasive actions and the deployment of flares designed to imitate the escape of aircraft that distract the missile seeker. However, due to the use of sophisticated signal processing in modern heat-seeking missiles, the effectiveness of infrared countermeasures is reduced due to reflective behavior. because a give is not as intuitively obvious as optical properties.

Early attempts at stealth were based on radar observations on existing designs. It was discovered early on that the shape of an aircraft determined its radar visibility, its radar cross section or RCS, for example, the British bomber of the 1960s, the Avro Vulcan, was noted to have a cross section of peculiarly small radar despite its large size, while the similarly sized Russian Tupolev 95 long-range bomber had an extremely prominent radar cross section. Other observations pointed towards the internal construction of the fuselage. Certain configurations of the internal structure of the fuselage can trap radiation causing reflections between the internal faces until the energy is dissipated.

This pseudo-technique was implemented on both the A12 and SR-71, while these observations pointed the designs in the right direction for truly effective stealth. A better understanding of radar. Diffraction was needed. The first steps to overcome this technological obstacle occurred in 1964, that year the Soviet mathematician and physicist Peter Youth himself published an article entitled Edge wave method in the physical theory of fraction in the Journal of the Moscow Radio Engineering Institute , expanding the theory. The work published by German physicist Arnold Sommerfeld in the defensive paper demonstrated the first major breakthrough in understanding the behavior of radar waves.

One woman's conclusion was that the radar force returned by an object is related to the configuration of its edges, not its size. His paper also demonstrated the ability to calculate the radar cross section along the surface of a wing and along its edge, the implications of this discovery were that even a large aircraft could reduce its radar signature by exploiting these. beginning. Surprisingly, the Soviet administration considered his work to have no military importance or economic value which allowed it to be published internationally during that period. Lockheed's elite design team was working on a stealthy proof-of-concept demonstrator called half blue.

The engineering team had trouble predicting stealth, as the program they created to analyze radar cross sections called echo one failed to produce accurate results. Denis Overholser, a stealth engineer on the project, had read it. FEM says the document He realized that he had created the mathematical theory and tools to do a finite analysis of radar reflection. The offensive work was incorporated into echo 1, allowing for more refined results. and accurate results Despite the objection of Skunk Works director Kelly Johnson, the faceted design was chosen due to its intended effectiveness. The iconic early stealth look was a direct byproduct of the computational limits of computers of the time, which limited the ability to perform calculations on curves.

Wooden mockups covered with metal sheets were built and the radar cross sections were later tested, confirming that Ecco wants predictions. His stealthiness was attributed to the difficulty of constructing his faceted body. Irregular edges. Using a wing sweep angle of 72 and 1/2 degrees. The inwardly inclined vertical tails known as an edge-aligned planned shape, the matching set of angles of the overall shape, work together to reduce the radar cross section. This worked by reflecting and scattering radar energy away from its source, making it difficult to detect and track simultaneously. Developed radar absorbing material was applied to the plane surfaces of the aircraft.

Special coatings were also applied to the windshield giving them metallic characteristics to reduce their infrared signature. Non-circular exhaust pipes were used to minimize the exhaust cross-sectional volume and maximize the mixing of hot exhaust gases with cold ambient air. It was also made subsonic to avoid detection by sonic boom. It was discovered that the rotating components of an engine Jet engines greatly increase radar observability to counter this the engine inlets were mounted on the top of the wings with the engine inlet covered by a low radar cross-section group during takeoff The inlet doors mounted on the The upper part would be opened to allow greater airflow because stealth was the top priority the shape of the plane made it inherently unstable a redundant quad-wire flight control system banned on the F-16 was integrated into the plane to give it flight characteristics.

Despite the loss of both demonstration aircraft, the aerodynamics and combat usability of the design were further refined, the aircraft was expanded in size, larger engines were installed, and two internal weapons bays were added. 117 Nighthawk was born out of these changes and reached a fully operational status in 1983. It was deployed in the 1989 US Forces invasion of Panama, but its capabilities were truly tested and Operation Desert Storm because The F-117 diverted radar energy away from its source, it was still possible to detect it using passive receivers located at different angles from the radar source, furthermore, its shape was so critical to its stealth that opening the weapons bay doors and Not retracting the antennas into the surface of the aircraft would significantly increase its radar cross section because this operational tactic played a large part of the stealth equation.

The missions were designed to avoid known vulnerabilities. The dependenceof tactics to mask their flaws would prove disastrous on March 27, 1999 during NATO's bombing campaign of Yugoslavia during raids. The F-117 would perform routine weapons bay door checks as they entered their targets because opening the weapons bay doors would increase radar. This was momentarily noted by Yugoslavia and army air defense operators with this knowledge were placing anti-aircraft missile batteries in advantageous positions and their radars configured to use longer wavelengths than those of the F-117 were designed so that the combination of These factors allowed the successful detection and subsequent shooting down of one of the stealth aircraft because the plane crashed almost intact was a severe blow to the United States. stealth advantage as the wreckage was reportedly sent to Russia and China for reverse engineering in 2008, the f-117 was eventually retired due to its old design, costly maintenance and being replaced by a new generation of stealth aircraft at as the blue program progressed.

Northrop began work on a technical demonstrator of its own known as Tacitus Blue, Tacitus Blue attempted to demonstrate a number of then-advanced technologies, including forms of stealth employing curved surfaces and the use of less radar-reflective composite materials in the late 1970s. Due to the success of the Han Blue and Tacit Blue programs were gaining momentum for the development of a deep penetration stealth bomber in 1979. The highly secret advanced tactical bomber program was initiated under the code name Aurora with the recent development of more advanced supercomputers that replaced what was available during the development of Echo. Complex radar cross-section calculations could be performed, allowing the design and analysis of combined curved shapes.

Northrop would eventually win as the best design option with its flying wing design with no protruding vertical surfaces. The flying wing design has an almost perfect Stealth shape. It offers no angles to reflect radar and an additional benefit of this design is the inherently small visual silhouette of the fuselage, which creates visual stealth and adds. Additionally, the majority of the aircraft was made of radar-absorbing carbon graphite composites and the parts are covered with radar absorbing materials. The internal fuselage structures are also designed to trap radiation similar to that of the F-117. The motors were buried deep within the frame, highly concealed. reflective opponents of the rotating engine to reduce its infrared signature the engines are mounted on the wings masking the exhaust in addition cold air is injected into the exhaust stream further reducing its heat signature the circulating cold fuel is also used to cool the exhaust sections of the aircraft as well as driving Aircraft surfaces that are heated with air friction additives are also dispensed into the exhaust stream under certain conditions to eliminate contrails designated as the b-2 spirit.

This flying wing design also offered efficient aerodynamics that gave it a range of 6,000 miles, but without vertical. Surfaces require fly-by-wire computer control to maintain stability. The B2 became fully operational in 1997 and its combat debut took place in 1999 during the Kosovo War. Its stealth and incredible range has allowed the B2 to participate in some of the missions. longest bombing runs During Operation Enduring Freedom, with more than 70 hours of flight around the planet to this day, it remains the stealthiest aircraft ever produced, while the F-117 was designated as a fighter, both it and The B2 were exclusively penetrating bombers without an air vent. -Air capability, this limited use of technology would soon change: in the early 1980s, the Air Force would submit a request for a new generation of air superiority aircraft, with stealth being high on the list of requirements, unlike of a bomber, the demands of a fighter.

Aircraft are more intensive, requiring speed, maneuverability and powerful radar and sensor packages. All of these requirements compete against stealth within a fighter design due to these trade-offs. The implementation of stealth and a fighter is not about total stealth, but about being the first to detect and fire at a target, the f-22 was designed to be fast and extremely agile in air-to-air combat using powerful engines. thrust vectoring with supersonic capability and traditional control surfaces. It carried low radar cross-section design cues from previous stealth programs that used edge shape refinements. coated deck, buried engines with masked entry design, composite construction, radar absorbing materials and internal weapons base.

The radar's low cross section was given higher priority at angles at which it would engage other aircraft, making it difficult to easily detect and track missiles, plus its stealthy surfaces were designed to evade radar wavelengths. smaller used by other aircraft, it also relied less on radar absorbing material due to its higher maintenance requirements. Tactically, the F-22 uses sensor fusion that links battlespace data from other aircraft and non-emitting sensors to avoid revealing its own position through radar emission overlapping with the F-22 program. Program work began on the F-35 stealth fighter in 1992. Design cues and technology from the F-22 found their way into the F-35.

Similar techniques were used to reduce radar cross sections. Notable differences are the use of stealthier tines instead of leading-edge extensions to improve maneuverability, an engine inlet that masks rotating components, and the use of more durable radar-absorbing materials similar to the F-22. More attention was paid to the radar wavelengths used by others. aircraft and missiles With the success and dominance of the US stealth program the technology has made its way into other applications, the canceled RH-66 Comanche reconnaissance helicopter, for example, was an attempt to employ stealth in an aircraft rotary wing. Other examples include naval programs such as the Sea Shadow and the USS Zumwalt, with unmanned aviation becoming The next frontier of stealth combat aviation technology is also being incorporated into the next generation of unmanned aerial combat vehicles, such as seen by the Grumman combat aviation.