Fourth - generation jet fighter Fourth - generation jet fighter is a general classification of fighter aircraft in service from approximately 1980 to present day , and represent design concepts of the 1970s . Fourth - generation designs are heavily influenced by lessons learned from the previous generation of combat aircraft . Long - range air - to - air missile s , originally thought to make dogfight ing obsolete , proved less influential than expected precipitating a renewed emphasis on maneuverability . Meanwhile , the growing costs of military aircraft in general and the demonstrated success of aircraft such as the F - 4 Phantom II gave rise to the popularity of multirole fighter s in parallel with the advances marking the so - called fourth generation . During the period in question , maneuverability was enhanced by relaxed static stability , made possible by introduction of the fly - by - wire ( FBW ) flight control system ( FLCS ) , which in turn was possible due to advances in digital computers and system integration techniques . Analog avionics , required to enable FBW operations , became a fundamental requirement and began to be replaced by digital flight control systems in the latter half of the 1980s . The further advance of microcomputers in the 1980s and 1990s permitted rapid upgrades to the avionics over the lifetimes of these fighters , incorporating system upgrades such as Active Electronically Scanned Array ( AESA ) , digital avionics buses and Infra - red search and track ( IRST ) . Due to the dramatic enhancement of capabilities in these upgraded fighters and in new designs of the 1990s that reflected these new capabilities , the US government has taken to using the designation 4 . 5th generation to refer to these later designs . This is intended to reflect a class of fighters that are evolutionary upgrades of the 4th generation incorporating integrated avionics suites , advanced weapons efforts to make the ( mostly ) conventionally designed aircraft nonetheless less easily detectable , and trackable as a response to advancing missile and radar technology ( see stealth technology ) . Inherent airframe design features exist , and include masking of turbine - blades and application of advanced sometimes radar - absorbent material s , but not the distinctive low - observable configurations of the latest aircraft , referred to as fifth - generation fighter s or aircraft such as the F - 22 Raptor and the F - 35 Lightning II . The United States Government defines 4 . 5 generation fighter aircraft as fourth generation jet fighters that have been upgraded with AESA radar , high capacity data - link , enhanced avionics , and " the ability to deploy current and reasonably foreseeable advanced armaments . " Design considerations . Performance . General performance has traditionally been the most important class of design characteristics , as it enables a fighter to gain a favorable position to use its weapons while rendering the enemy unable to use theirs . This can occur at long range ( beyond visual range or BVR ) or short range ( within visual range or WVR ) . At short range , the ideal position is to the rear of the enemy aircraft , where it is unable to aim or fire weapons and the hot exhaust makes a good target for infrared - guided missiles . At longer BVR range , the probability of a successful missile intercept is improved by launch at high energy , kinetic ( the aircraft ' s speed towards its target ) and potential ( altitude advantage ) . Being able to maneuver violently , and without losing energy meanwhile increases the chance of evading enemy missiles , or escape out of range of the likely return - fire . These two scenarios have competing demands — interception requires excellent linear speed , while Within Visual Range or WVR engagements require excellent turn rate , while maintaining speed , rapid acceleration , and availability of control at low speeds and high angle of attack . Prior to the 1970s , a popular view in the defense community was that missiles would render WVR combat obsolete and hence maneuverability useless . Combat experience proved this untrue due to the poor quality of missiles and the recurring need to identify targets visually . Though improvements in missile technology may make that vision a reality , experience has indicated that sensors are not foolproof and that fighters will still need to be able to fight and maneuver at close ranges . So whereas the premier third - generation jet fighter s ( e . g . , the F - 4 and MiG - 23 ) were designed as interceptors with only a secondary emphasis on maneuverability , interceptors have been relegated to a secondary role in the fourth generation , with a renewed emphasis on maneuverability . While the trade - offs involved in combat aircraft design are again shifting towards BVR engagement , the management of the advancing environment of numerous information flows in the modern battle - space , and low - observability , arguably at the expense of maneuvering ability in close - combat , the application of thrust vectoring provides a way to maintain it , especially at low speed . There are two primary contributing factors to maneuverability — the amount of thrust delivered by the engines , and the ability of the aircraft ' s control surfaces to efficiently generate aerodynamic forces , and hence alterations in the plane ' s direction . Air - combat maneuvering ( ACM ) involves a great deal of energy management . The greater energy a fighter has , the more flexibility it has to move where it wants . An aircraft with little energy is immobile , and becomes a defenseless target . Note that available thrust does not necessarily equal speed ; while it does give greater acceleration , the maximum speed of an aircraft is also determined by how much drag it produces . Herein lies one important trade - off . Low - drag configurations have small , often highly swept wings that disrupt the airflow as little as possible . However , that also means they have greatly reduced ability to alter the airflow to maneuver the aircraft . There are two rough indicators of these factors . A plane ' s turning ability can be roughly measured by its wing loading , defined as the mass of the aircraft divided by the area of its lifting surfaces . A highly loaded wing has little capacity to produce additional lift , and so has limited turning ability , whereas a lightly loaded wing has much greater potential lifting power . A rough measure of acceleration is a plane ' s thrust - to - weight ratio . Fly - by - wire . The fourth generation jet fighter defining point is fly - by - wire , like 4 . 5 is defined on AESA radar . YF - 16 was the world ’ s first aircraft intentionally designed to be slightly aerodynamically unstable . This technique , called " relaxed static stability " ( RSS ) , was incorporated to further enhance the aircraft ’ s performance . Most aircraft are designed with " positive " static stability , which induces an aircraft to return to its original attitude following a disturbance . However , positive static stability ; the tendency to remain in its current attitude ; opposes the pilot ’ s efforts to maneuver . On the other hand , an aircraft with " negative " static stability will , in the absence of control input , readily deviate from level and controlled flight . An aircraft with negative static stability can therefore be made more maneuverable . At supersonic airspeed , a negatively stable aircraft can exhibit positive static stability due to aerodynamic center migration . To counter this tendency to depart from controlled flight — and avoid the need for constant minute trimming inputs by the pilot — the 4th gen aircraft has a quadruplex ( four - channel ) fly - by - wire ( FBW ) flight control system ( FLCS ) . The flight control computer ( FLCC ) , which is the key component of the FLCS , accepts the pilot ’ s input from the stick and rudder controls , and manipulates the control surfaces in such a way as to produce the desired result without inducing a loss of control . The FLCC also takes thousands of measurements per second of the aircraft ’ s attitude , and automatically makes corrections to counter deviations from the flight path that were not input by the pilot . Coordinated turn is also achieved in the same way , processing thousands of instructions per second to synchronize yawing and rolling to minimize sideslip drag in turns . Thrust vectoring . Thrust vectoring is a technology introduced to further enhance a fighter ' s turning ability , introduced in Soviet fighters . By redirecting the jet exhaust , it is possible to directly translate the engine ' s power into directional changes more efficiently than via the plane ' s control surfaces . The Sukhoi Su - 27 was the first aircraft to display publicly thrust vectoring for pitch ( called 2D TVC ) , making the aircraft highly maneuverable , capable of near - zero airspeed at high angles of attack without stalling , and dynamic aerobatics at low speeds like Pugachev ' s Cobra . The TVC nozzles of the MKI are mounted 32 degrees outward to longitudinal engine axis ( i . e . in the horizontal plane ) and can be deflected ±15 degrees in the vertical plane . This produces a corkscrew effect , greatly enhancing the turning capability of the aircraft . The MiG - 35 with its RD - 33OVT engines with the vectored thrust nozzles allows it to be the first twin - engine aircraft with vectoring nozzles that can move in two directions ( that is , 3D TVC ) . Other existing thrust vectoring aircraft , like the Su - 30MKI and the F - 22 , have nozzles that vector in one direction . The technology has been fitted to the Sukhoi Su - 47 Berkut and later derivatives . The U . S . explored fitting the technology to the F - 16 and the F - 15 , but only introduced it on the F - 22 Raptor . Supercruise . Supercruise is the ability of aircraft to cruise at supersonic speeds without the afterburner . Because of parasitic drag effects , fighters carrying external weapons stores encounter a vastly increased drag divergence near the speed of sound . This can prevent safe acceleration through the transonic regime , or make it too fuel - expensive to be effective on missions . Meanwhile , maintaining supersonic speed without ( periodic ) afterburner use saves large quantities of fuel too , increasing the range at which an aircraft can in reality still take advantage of its full performance . According to the German Air Force the Typhoon can cruise at about Mach 1 . 2 without afterburner . The manufacturer claims that the maximum level speed possible without reheat is Mach 1 . 5 . An EF T1 DA ( Development Aircraft trainer version ) demonstrated supercruise ( 1 , 21M ) with 2 SRAAM , 4 MRAAM and drop tank ( plus one tonne flight test equipment , plus 700 kg more weight for the trainer version ) during the Singapore evaluation . The Dassault Rafale can supercruise , in dry power , even with four missiles and a 1 , 250 - liter belly drop tank and even in the naval version ( Rafale M ) . Sukhoi Su - 35 can also supercruise at speed of Mach 1 . 6 Avionics . Avionics is a catch - all term for the electronic systems aboard an aircraft , which have been growing in complexity and importance . The main elements of an aircraft ' s avionics are its communication and navigation systems , sensors ( Radar and IR ) , computers and data bus , and user interface . Because they can be readily swapped out as new technologies become available , they are often upgraded over the lifetime of an aircraft . Details about these systems are highly classified . Thus , many export aircraft have downgraded avionics , and buyers often replace them with domestically developed avionics , sometimes considered superior to the original . Examples are the Sukhoi Su - 30MKI sold to India , the F - 15I and F - 16I sold to Israel , and the F - 15K sold to South Korea . The primary sensor for all modern fighters is radar . The U . S . fielded its first modified F - 15Cs equipped with APG - 63 ( V ) 2 AESA radars , which have no moving parts and are capable of projecting a much tighter beam and quicker scans . Later on , it was introduced to the F / A - 18E / F Super Hornet and the block 60 ( export ) F - 16 also , and will be used for future American fighters . A European coalition GTDAR is developing an AESA radar for use on the Typhoon and Rafale , and Russia has an AESA radar on its MIG - 35 and their newest Su - 27 versions . For the next - generation F - 22 and F - 35 , the U . S . will use Low Probability of Intercept ( LPI ) capacity . This will spread the energy of a radar pulse over several frequencies , so as not to trip the radar warning receivers that all aircraft carry . In response to the increasing American emphasis on radar - evading stealth designs , Russia turned to alternate sensors , with emphasis on infra - red search and track ( IRST ) sensors , first introduced on the American F - 101 Voodoo and F - 102 Delta Dagger fighters in the 1960s , for detection and tracking of airborne targets . These measure IR radiation from targets . As a passive sensor , it has limited range , and contains no inherent data about position and direction of targets - these must be inferred from the images captured . To offset this , IRST systems can incorporate a laser rangefinder in order to provide full fire - control solutions for cannon fire or for launching missiles . Using this method , German MiG - 29 using helmet - displayed IRST systems were able to acquire a missile lock with greater efficiency than USAF F - 16 in wargame exercises . IRST sensors have now become standard on Russian aircraft . With the exception of the F - 14D ( officially retired as of September 2006 ) , no 4th - generation Western fighters carry built - in IRST sensors for air - to - air detection , though the similar FLIR is often used to acquire ground targets . The Eurofighter Typhoon designated ' 4 . 5th generation ' ( beginning with Tranche 1 Block 5 aircraft , while previously build aircraft are being retrofited since spring 2007 ) and the F - 35 s will have built - in , PIRATE IRST sensors , a feature adopted early in the design , meanwhile beginning in 2012 the Super Hornet will also have an IRST . The tactical implications of the computing and data bus capabilities of aircraft are hard to determine . A more sophisticated computer bus would allow more flexible uses of the existing avionics . For example , it is speculated that the F - 22 is able to jam or damage enemy electronics with a focused application of its radar . A computing feature of significant tactical importance is the datalink . All modern European and American aircraft are capable of sharing targeting data with allied fighters and AWACS planes ( see JTIDS ) . The Russian MiG - 31 interceptor also has some datalink capability , so it is reasonable to assume that other Russian planes can also do so . The sharing of targeting and sensor data allows pilots to put radiating , highly visible sensors further from enemy forces , while using that data to vector silent fighters toward the enemy . Stealth technology . Stealth technology is an extension of the notion of visual camouflage to modern radar and IR detection sensors . While not rendering an aircraft " invisible " as is popularly conceived , stealth makes an aircraft much more difficult to discern among the sky , clouds , or distant aircraft , conferring a significant tactical advantage . While the basic principles of shaping aircraft to avoid detection were known at least since the 1960s , it was not until the availability of supercomputers that shape computations could be performed from every angle , a complex task . The use of computer - aided shaping , combined with radar - absorbent materials , produced aircraft of drastically reduced radar cross section ( RCS ) that were much more difficult to detect on radar . Meanwhile advances in digital flight control make potentially destabilizing , or control - complicating effects of shape alterations easier to compensate for . During the 1970s , the rudimentary level of stealth shaping ( as seen in the faceted design of the F - 117 Nighthawk ) resulted in too severe a performance penalty to be used on fighters . Faster computers enabled smoother designs such as the B - 2 Spirit , and thought was given to applying the basic ideas to decrease , if not drastically reduce , the RCS of fighter aircraft . These techniques are also combined with methods of decreasing the IR , visual , and aural signature of the aircraft . While fighters designated 4 . 5th generation under the US - devised system incorporate some low - observable features , so - called fifth generation fighter s have more clearly been designed with this as a very high priority . The inclusion of this as a criterion for the designation of " fifth generation " serves to illustrate the degree to which US manufacturers and their clients appear to assign value to this capability . There are some reports that the Dassault Rafale ' s avionics , the Thales Spectra , includes " stealthy " radar jamming technology , and systems for the active cancellation of RADAR analogous to the acoustic noise suppression systems on the De Havilland Canada Dash 8 . Conventional jammers make locating an aircraft more difficult , but their operation is itself detectable , with missiles being designed more recently to endeavor to follow the jamming itself . The French system is hypothesized to interfere with detection without revealing that jamming is in operation . Such a system ought in principle to be able to make an aircraft entirely invisible , were it to be feasible to actively mimic an undisturbed RADAR signature ( canceling all reflections , and compensating for any RADAR shadow ) however such a system would be incalculably difficult and is not envisaged . Meanwhile the real effectiveness of systems that allegedly exist is unknown . Research continues into other ways of decreasing observability by radar . There are claims that Russian researchers are working on " plasma stealth " . Obviously , such techniques might well remove some of the envisaged advantages held by fifth generation aircraft , adding to skepticism over the real value of the " generation " label , which seems to assume the superiority and uniqueness of particular design philosophies . There are in any case ways to detect fighters other than radar . For instance , passive infra - red sensors can detect the heat of engines , and even the sound of a sonic boom ( which any supersonic aircraft will make ) can be tracked with a network of sensors and computers . However , using these to provide precise targeting information for a long - range missile is considerably less straightforward than radar . Combat performance . The F - 15 and F - 16 have the first and second best known overall combat records of modern jet fighters . F - 15s have a claimed combat record of 101 victories and zero losses in actual air to air combat . Such statistics may be of limited use in comparing aircraft since the quality of the opposition and other factors are not taken into account . Exercise reports . Different air forces regularly practice against each other in exercises , and when they fly different aircraft some indication of the relative capabilities of the aircraft can be gained . During the " Cope India ' 04 " exercise ( 2004 ) , USAF F - 15 Eagles were pitted against Indian Air Force Su - 30MKs , Mirage 2000s , MiG - 29s and aging MiG - 21 s . The results have been widely publicized . The " Cope India 2005 " exercise was conducted with teams that used a combination of United States and Russian - designed aircraft . The " Christian Science Monitor " ( CSM ) reported that “ both the Americans and the Indians won , and lost . ” According to the same article the Indian air force designed Cope 2005 in that the rules of engagement be that the forces fight within visual range , and both forces could not take advantage of their long range sensors or weapons . In July 2007 , the Indian Air Force fielded the Sukhoi Su - 30MKI during the " Indra - Dhanush " exercise with Royal Air Force ' s Eurofighter Typhoon . This was the first time that the two jets had taken part in such an exercise . The IAF did not allow their pilots to use the radar of the MKIs during the exercise so as to protect the highly - classified N011M Bars . " RAF Tornado pilots were frank about the shameful display of the lack of maneuverability in the Su - 30MKI , just as they had anticipated , but the IAF pilots were in complete awe by the Typhoon ' s superior agility in the air " . RAF Tornado pilots were candid in their admission of the Su - 30 MKI ' s superior manoeuvring in the air , just as they had anticipated , but the IAF pilots were also impressed by the Typhoon ' s agility in the air . http : / / www . airsceneuk . org . uk / hangar / 2007 / 441indians / indra . htm