Article by Karanveer Singh
Since, the aircrafts being fabricated for military use, element of surprise is the huge factor determining the survivability of airplane and outcome of any operation. Today, a number of fighter jets are in use that can hunt any enemy aircraft down without being detected called as
Stealth aircrafts or 5th generation aircrafts. But, Stealth technology (Low observable technology) has come a long way to reach the present face and this article is going to deal with background, need, evolution, Present scenario and future of stealth technology.
During the World War 1, aircrafts were having only small roles such as reconnaissance but in year 1935 , a British inventor Sir Robert Watson Watt invented the 1st practical RADAR system and further developments worldwide enabled to trace the speed, size and altitude of any incoming threat/object. That is where the requirement of stealth technology was felt and endeavours changed the aviation and military industry. In 1940, a DE Havilland Mosquito aircraft was the first aircraft to keep Stealth factor in mind. The aircraft was mainly made of wood due to which it had low RADAR signature and further advancements were followed.
Before digging directly into Stealth technology, we need to understand how it was felt to be necessary and how research data to be applicable over the world’s 1st Stealth aircraft “F117 Nighthawk”. In year 1945, after the surrender of Germany, as the World War 2 ended , in order to maintain the regional supremacy over the Eastern Europe, it lead to eruption of cold war between two super powers – USA and USSR. The cold war was an on-going political rivalry of USA, USSR and their allies due to which all nations were pushing hard to develop their military and regional dominance for any future war. A lot of nuclear tests were being done by both the superpowers that lead to treaties be signed by superpowers after UN intervention. Americans were not having any trust on Russians and that is why, America developed a series of spy De Havilland Mosquito light bomber planes for reconnaissance from the skies of USSR and to catch every little information about military bases, nuclear tests, aircraft development and many more through aerial photographs. In order to develop such series without being known by world lead to the birth of “Skunk Works” which was a pen name of Lockheed Martin and in the Area 51 ( Edward’s Air Force Base ) engineers incorporated Skunk Works designed and fabricated some of the most advanced aircrafts like U-2 Spy-plane , SR-71 Blackbird ( Strategic Reconnaissance -71) and F117 Night Hawk while the research data obtained was used to develop more advanced fighter jets such as F22 Raptor , F35 Lightning , YF-23 Black Widow (Prototype) and B-2.
One of the most renowned aircraft designers of the time ,“Clarence „Kelly‟ Johnson” became the chief of Skunk Works and vectored the operations with his ideas, creativity and calibre that lead to aerospace industry be changed setting new milestones. The first aircraft being developed by Skunk Works was U-2 spy plane which was being designed to fly at the altitude of 50,000 feet because the RADARs on that time were not such advanced to track an object at this much height. It was a light, single seat with a wingspan of 31 meters due to which it was called as “Flying Cross” as well. U-2 brought a lot of information to Americans until Russians came up with better RADARs and development in air defence missile systems lead U-2 spy plane to be shot multiple times by Russian missiles and hence its was abrogated.
Kelly Johnson (Then chief of Skunk Works ) realised the situation and summoned his team to work on a never being known before aircraft that could fly at the altitude of 85000 feet with a speed of Mach 3+. The project lead to development of well-known SR-71 Blackbird which was a pioneer in aviation history. SR – 71 being capable to fly at the altitude of 85000 feet maintaining the speed of Mach 3.2 for multiple hours was beyond enemy range in any way as no RADAR could detect it and even if it is detected and an interceptor missile is being fired over it, it was practically untouchable due to its speed. SR-71 incorporated various stealth features which were broadly used to avoid detection.
The airframe consisted of chines U 2 Spy plane (Blended wing type structures ) which is highly used in stealth aircrafts with triangular (reflecting geometry) structure to dissipate the RADAR wave‟s energy. The aircraft was coated with RADAR absorbing paint which comprises of microscopic iron balls that dissipate the energy of RADAR waves in the form of heat and hence avoid detection. In order to reduce the heating effect and overcome infrared detection, aircraft was painted in black because of whom it got its name “Blackbird”. Highly powerful Pratt & Whitney J-58 engines were employed with Turbo-RAM configuration ( Bypassing the air directly to afterburner after compression at a particular speed ) along with retractable nose cone for shock wave management and pressure recovery enabling engines to work at a wide range of speeds with ease providing high thrust .
As the reconnaissance through satellites and air defence systems improved , SR-71 was retired and Ben Rich (2nd chief of Skunk Works) came with an idea to make the aircraft invisible to RADAR. Initially ,the concept was criticized due to aerodynamic unstable design and also regarded as “Hopeless Diamond” but in June 1981, the aircraft proved its potential during a test flight and researchers saw great potential and this is how Modern stealth came into play where not only special surfaces along with coatings were employed to make an aircraft invisible to RADAR but also using special propulsion airframe integration to acquire thermal camouflage as well.
The experimentation results were employed to develop modern 5th generation fighters such as YF -23 BlackWidow, F -22 Raptor , F-35 and so on. 5th generation airplanes not only incorporate stealth features but also carry a wide range of capabilities such as beyond visual range targeting, high maneuverability etc. These aircrafts are equipped with better computer systems comprises of electronic warfare suit , thermal tiles in nozzles, Planform alignment (identical sweep angle of leading edge and trailing edge of wings and tail), canted vertical stabilizer, toothed canopy seam and bay , internal weapon bay , extensive composite material SR-71 Blackbird use, serpent inlet duct , deep seated turbine vanes and specially designed nozzles for optimum performance and low thermal signature along with low acoustic signature. All this could be possible because of highly advanced computer systems that can perform various simulation united with the years of thorough research and experimentation for curve and contour correction enabling better aerodynamic performance coupled with stealth status.
Weapon systems of 5th generation aircrafts mainly comprises of BVRAAMs ( Beyond Visual Range Missiles ) , precision guided weapons , electronic jamming etc. As the modern airplanes have acquired huge capabilities, the name “Supersonic Assassins” completely suit them.
Looking upon the potential trends and development in the field of aerospace industry and the areas specially being focused at, one can predict the expected future. Upcoming generation or 6th generation aircrafts are expected to be having all – aspect stealth with passive detection. As the control surfaces are highly responsible for RADAR signature, some concepts have formulated to control the aircraft by supersonic ejection of air to generate turning moments hence making an aircraft to roll, pitch or yaw. 6th generation aircrafts might not be having vertical stabilizer as being showcased in the FA-XX concept of US Navy and Chinese conceptual fighters. These aircrafts would be equipped with laser based weapon systems in which a high energy laser would be used to neutralize any incoming target and the field is still under extensive research followed by extensive research on propulsion systems making aircrafts capable to climb at further high altitudes, high range , endurance including better and optimized nozzles for low thermal signature as well as higher thrust efficiency. In a nutshell , we can assume that 6th generation aircrafts might be just upgraded versions of 5th F22 Raptor (5th generation fighter) generation aircrafts with increment or addition in capabilities.
In the end of day, Stealth technology have shaped the modern military aviation and beyond as well. The rivalry among the nations brought aircrafts with huge capabilities that are improving day by day reaching ultimate heights with maintaining the tag “SUPERSONIC ASSASIN”.