In 1968, the United States started a new aircraft project. The requirements of the F-X project were 40,000 lb. MTOW, a maximum speed of 2.5 Mach, and a high thrust-to-weight ratio. In 1969, McDonnell-Douglas's F-15 was selected. As the F-X project continued, the challenges of equipping the Air Force with such a capable and expensive aircraft began to arise. The team that led the debate was nicknamed the "Fighter Mafia" at the time. The Fighter Mafia believed that the ideal fighter should be light and highly maneuverable. Thus, it could easily change its speed, altitude, and direction. The light, and therefore small, plane would also be cheaper to manufacture and operate. Later, the Fighter Mafia's ideas started to be valued. The Advanced Day Fighter concept emerged and was named the F-XX project. With the support of the Department of Defense, the Air Force Prototype Study Group was established in May 1971. Two of the six candidates were selected, and the Lightweight Fighter (LWF) project was initiated. The USAF requested a fast and high maneuverable aircraft that weighs 20,000 lb. and is optimized for combat at Mach 0.6 - 1.6 at an altitude of 30,000 - 40,000 feet. In May 1972, the proposals of General Dynamics and Northrop were selected, and the YF-16 and YF-17 prototypes were manufactured. With the U.S. Air Force's desire to replace its F-4 and F-105 aircraft, the LWF project later turned into the Air Combat Fighter (ACF). The YF-16 aircraft had also evolved into a multi-role fighter from a day fighter, and the number of its underwing pylons was increased from two to three. The radar requirements were also changed, and the Westinghouse APG-66 multi-mode mission radar was selected. On June 13, 1975, the U.S. Air Force announced that it had chosen the YF-16. In this choice, the P&W F100 turbofan engines used in the F-15 aircraft played a significant role as much as the YF-16's superior acceleration, climbing, and maneuverability to the YF-17. This selection also reduced engine unit costs and operating costs. Thus, with this decision of the U.S. Air Force, the F-16 legend was born. 

The resulting lightweight fighter incorporated various advanced technologies that were not previously used in operational aircraft. A LERX (leading-edge root extension), which is a small extension to an aircraft wing surface, is added forward of the leading edge to improve the airflow at high angles of attack and low airspeeds. Additionally, the aircraft's response time was reduced by using the fly-by-wire system instead of the heavier hydraulic system. The YF-16 is the first aircraft designed and manufactured to be aerodynamically unstable. This characteristic, which is also known as Relaxed Static Stability (RSS), increases the agility of the plane. By its very nature, a stable aircraft wants to switch to a level flight if its controls are released. This is called Positive Static Stability. RSS planes require numerous control inputs or trim changes to fly. On the other hand, these momentary changes are executed by the F-16's onboard computer, which is integrated into the fly-by-wire system to ensure that the aircraft flies properly. The ejection seat reclined 30 degrees from vertical to reduce the effect of g-forces on the pilot. The plane also features a side-mounted control stick to ease control while maneuvering. Thanks to HOTAS, HUD, and the bubble canopy, the pilot's situational awareness was increased. All these technologies had been tried in some aircraft and research programs before. But with the YF-16, it was the first time that they all came together in a production aircraft. 

The F-16 gained new capabilities over time, starting from the initial design phase. If you look at the latest F-16E/F Block 60 or F-16Vs, you'll see that they have completely different capabilities, although they are physically similar to the F-16A/B Block 1s produced in the late 1970s. All significant changes in the F-16 fighters are displayed in Block numbers. As block number increases, the aircraft's capabilities also increase. More than 4,500 planes were manufactured under 8 main models in 139 different configurations and were used by 29 countries. More than 3,000 operational F-16s are in service today.

F-16V "VIPER" Block 70/72

Lockheed Martin started to work on Block 70/72 to provide F-16 users with new capabilities needed in the current combat environment. The "Mid-Life Update" (MLU) program, which will be applied to existing F-16 aircraft, is aimed to be the same level as the new aircraft (Block 70/72). The Northrop Grumman AN/APG-83 SABR (Scalable Agile Beam Radar) radar forms the center of the program. Another important feature of the F-16V configuration is the CPD (Center Pedestal Display). With its high resolution 6 x 8-inch display, it allows the pilot to take full advantage of the AESA and Targeting Pod data. The Auto GCAS (Automatic Ground Collision Avoidance System) system has become standard with Viper configuration. Thanks to this system, the aircraft performs a self-rescue maneuver without pilot intervention to prevent collisions if the pilot passes out from high G force or if the aircraft loses altitude due to disorientation. Compared to previous models, the service life of the aircraft is increased by 50% to 12,000 hours, with structural reinforcement so that the aircraft can operate for many more years. 

The most important capability enhancement of this modernization is the Northrop Grumman AN/APG-83 SABR AESA radar (Scalable Agile Beam Radar / Active Electronically Scanned Array). It has approximately 1000 TRM (Transmit - Receive Module) in the 10kW class, which can detect aerial targets at a maximum distance of 300 km. While the AN/APG-68(V)9 radar can detect a target with a radar cross-section of 1 m2 at a distance of 70km, the AN/APG-83 radar can detect it at 135 km. The AN/APG-83 can simultaneously track more than 20 aerial targets along the 120° angle in front of the aircraft. Northrop Grumman states that the new radar is lighter and five times more reliable than the conventional AN/APG-68. The software of the AN/APG-83 is 95% similar to the software of the AN/APG-81 radar produced for the F-35. SABR also features high-resolution SAR (Synthetic Aperture Radar) capability. It can also perform automatic target recognition and target cueing (ATC) with the SAR mode and detect ground targets within 300 km with its GMTI (Ground Moving Target Indication) feature. In addition, the radar can operate in a contested electromagnetic spectrum environment and features all-weather, high-resolution synthetic aperture radar mapping to present the pilot with a large surface image for more precise target identification and strike capabilities. It can also simultaneously operate in both air-to-air and air-to-ground modes, while it is not possible to do this with the legacy AN/APG-68. APG-83 SABR is also fully integrated with L3Harris' ALQ-254(V)1 Viper Shield all-digital electronic warfare (EW) suite.

The first flight tests of the AN/APG-83 radar on the F-16 began in November 2009 at Edwards Air Base. The production process was accelerated when Taiwan chose the SABR for its F-16V modernization. The AN/APG-83 SABR has now become an important part of this modernization package and the standard radar for the new production F-16C/D Block 70/72 aircraft.

Another key feature of the F-16V configuration is the Center Pedestal Display (CPD), which provides critical tactical imagery to pilots on a high-resolution 6" x 8" screen. The high-resolution display allows the pilot to take full advantage of AESA, giving the pilot enhanced battlefield awareness with full color moving maps. The new CPD enables larger and easier to manage air-to-air Situation Displays, zoom functionality with the ability to switch information among displays, and digital display of Flight Instrument Data. 

Developed by Raytheon, the MMC7000 (Modular Mission Computer) has twice the processing power and 40 times the memory of the previous mission computer. The single, high-performance MMC7000 replaces the three original computers on the F-16V, reducing weight by 55%, volume by 42%, and power usage by 32%.

Another major capability enhancement that comes with the Viper is Lockheed Martin's Legion-ES (Embedded System) Infrared Search and Track (IRST) pod. The Legion-ES is basically a repackaging of the Long-wave infrared (LWIR) sensor developed for the Legion pod and IRST21. As the usable space in the F-16's front equipment compartment has increased with the Viper modernization, the electronics of the Legion-ES can be placed here. The 300 lb. and 77" long Legion-ES pod is installed to the pylon on the left side of the air intake. 

The F-16 has been the western block's best-selling and naturally the most-used aircraft for many years. It seems to keep its place in the future, both with Block 70/72 and V modernization. Bahrain 16, Taiwan 66, Morocco 24, Bulgaria 8, and Slovakia ordered 14 new production Block 70/72 aircraft. In addition, Morocco (23), Taiwan (142), Greece (85), South Korea (134), and Singapore (60) will upgrade their F-16s to V configuration. Last year, Turkey also applied to the United States to purchase 40 new production Block 70 fighters and 80 V modernization kits. Turkey was excluded from the F-35 program due to the S-400 missile system and faced CAATSA sanctions. While it is expected that Turkey's request will be answered negatively under normal conditions, Russia's invasion of Ukraine changed the balances in the region, and how the USA will respond to Turkey's request is eagerly awaited by those in defense industry circles.

Since its first flight, the evolution of the F-16 has continued. With its new radar, avionics, secure data link, and electronic warfare systems, Viper has now turned into a 4.5 generation aircraft that can perform joint operations with fifth-generation aircraft