SHORT FEATURE ARNAB CHATTERJEE ITH the advent of the First World enemy. Modern stealth aircraft employ discharges its weapon to attack its target. WWar in the early 20th century, various methods to reduce their radar Aircraft engines are often set within the defense technology began advancing at a and infrared signatures. Stealth bomber fuselage which reduces radar signature. great pace. All countries involved in this aircraft like the Northrop Grumman B-2 Of the earlier stealth aircraft, the devastating war started stepping up their Spirit, which is capable of delivering Lockheed SR-71 Blackbird utilized technologies in order to outsmart and in nuclear weapons, become virtually composite materials in strategically turn defeat their enemies. invisible to radar detection by having a important locations and had canted Aviation technology was also very negligible signature. vertical stabilizers along with Radar revolutionized as nations realized the The primary factor in a stealth aircraft Absorbent paint to signifi cantly reduce potential of an aerial attack which has the is its design. Stealth aircraft are designed its radar cross section although it mainly capacity to devastate the morale of people to decrease their radar cross section relied on its high cruising altitude and its and can easily inhibit the war effort by so that the waves that are transmitted supersonic speed. eliminating strategically important targets towards the aircraft are either absorbed Lockheed Martin F-117 Nighthawk such as industrial parks. Consequently, or are largely defl ected. A stealth aircraft was the fi rst military stealth aircraft detecting such enemy aircraft assumed avoids rounded aerodynamic surfaces to come under service, but its radical importance as a defensive system. which are unable to defl ect radio waves design to counter radar waves made it After the First World War, many transmitted perpendicularly on its surface aerodynamically unstable and thus it nations secretly started developing and thus compromising its position. could not be controlled without fl y-by- researching on the radar and its potential Stealth aircraft also absorb radar wire controls. use to serve as an early warning system signatures by usage of RAM or Radar With the advent of thrust vectoring before the actual attack took place. Absorbent Material. Although most Radar technology and advanced avionics, Research on radar technology rapidly Absorbent Material are classifi ed, the stealth fi ghter aircraft like the Lockheed continued throughout the war years and most common type of Radar Absorbent Martin F-22 Raptor gained greater the British were the fi rst to use radar as Material that was used in early stealth a defensive measure to detect incoming aircraft such as the Lockheed Martin enemy aircraft during the Battle of Britain F-117 Nighthawk and the Lockheed SR- B-2 Stealth Bomber in 1940. 71 Blackbird was “Iron Ball Paint”. In this This rapid growth of radar process, the aircraft’s surface is painted technology was subsequently countered with tiny metallic spheres coated with by stealth technology which could make ferrite. When radar waves fall on this aircraft virtually undetectable to radars. surface, they cause molecular oscillations One of the fi rst aircraft on which this in these spheres thus turning the incident technology was put to practice was radar energy into heat which is dissipated. the Horten Ho 229. The aircraft was a The design of a stealth aircraft has fl ying wing design and its employment also to deal with protrusions that can of charcoal with the wood glue of the compromise its stealth. Thus, all modern airplane made it absorb radio waves. stealth aircraft mostly store their entire A stealth aircraft’s primary job is to payload inside their wing or fuselage complete its mission undetected by its which is only compromised when it SCIENCE REPORTER, JULY 2014 36 SHORT FEATURE F-22 Raptor (Courtesy: www.en.wikipedia.org) Northrop experimental stealth aircraft maneuverability along with stealth aircraft like F-117 Nighthawk by tilting corrections by the digital fl y-by-wire technology which gave them a greater their tail surface or as in case of the B-2 control system onboard the aircraft. They edge over conventional fi ghter aircraft. Spirit, a presence of a vertical stabilizer is also lacked afterburners which were The Raptor can also conduct small completely eradicated. necessary to give them an extra boost bombing missions virtually undetected, Along with radar, aircraft were also of thrust for speed as it would make thus also claiming greater versatility over detectable by infrared rays and thus to them susceptible to infrared detection conventional fi ghter-bombers. keep the title of being a stealth aircraft, by the heat emitted. However, with the All stealth aircraft have a radical engine exhausts of early stealth aircrafts utilization of modern design techniques, design as compared to other conventional were set in the fuselage like that of the this has been avoided in newer stealth aircraft. The Northrop Grumman B-2 B-2 Spirit. The exhaust is thereby cooled aircrafts like the F-22 Raptor and the Spirit is a fl ying wing design which by the air following the surface of the F-35 Lightning which are now able to uses split rudders as it has no distinct wing. Also positioning fuel lines or incorporate afterburners like conventional empennage. The Lockheed Martin F-35 tanks near the exhaust makes them act fi ghter aircrafts. Lighting II has also incorporated V/STOL as heat absorbers thus reducing infrared Stealth aircraft can also give away capability (Vertical/Short Take Off and signature. their position due to externally mounted Landing) along with its stealth and thus Stealth aircraft have a great aerial payloads which cannot be stored has achieved even greater versatility as advantage over conventional aircraft internally inside the aircraft as their it needs very less space to operate from. as they can penetrate deep into enemy internal payload capacity is quite reduced Aircraft like the F-35 Lightning and F-22 territory without being detected and thus due to design considerations. Raptor use planform alignment, which reduce life risk factor for the pilots. Also Modern stealth aircraft, especially involves using small number of surface with the major involvement of computer stealth fi ghter aircraft have overcome orientations in the shape of its structure systems in the cockpits of modern aircraft, these shortcomings due to more to avoid radar detection while corner a lot of work can be done easier and advanced design techniques and avionic refl ections of radar waves are reduced by quicker thus making it possible for as little technologies. Stealth aircraft also give as four people to successfully complete a military operators the element of surprise. Stealth aircraft also give military mission which would previously require The F-22 and F-35 can conduct strikes at operators the element of surprise. more crew and support aircraft. supersonic speeds under the full cover of The F-22 and F-35 can conduct In spite of having an upper hand in stealth minimising loss of human life as strikes at supersonic speeds under modern aerial warfare, stealth aircraft systems on board can pinpoint targets and the full cover of stealth minimising do have a few limitations. They utilize a destroy them without causing damage to loss of human life. variety of composite and radar absorbent the surroundings. Pilots operating inside material to inhibit detection by stealth aircraft feel a lot safer than while infrared and radar. However, conducting missions on conventional aircraft that have radar absorbent aircraft as they can accomplish their skin are comparatively sensitive mission undetected by the enemy. than conventional aircraft skins. Even though stealth aircraft are Stealth aircraft also spend undoubtedly one of the greatest military a long time on the assembly aviation technologies that the world has line before they are fi nally come up with, we just hope we do not get fi nished and are much more to see them in action on real battlefi elds. expensive than conventional military aircraft. Aerodynamic Arnab Chatterjee is a student and a NASA DashLink Researcher, which is a part of NASA’s instabilities also often bothered Aviation Safety Program under NASA’s Aeronautics F-117A Nighthawk aircraft like the F-117 Nighthawk Research Mission Directorate. Address: C/o Amit and the B-2 Spirit which would Chatterjee, 32, Muktarpara, 1st Lane, Hatkhola, have been highly instable to Chandannagar, West Bengal-712136; Email: rnb. control without the constant [email protected] 37 SCIENCE REPORTER, JULY 2014.