The F-16 Fighting Falcon is a compact, multirole fighter aircraft. It is highly maneuverable and has proven itself in air-to-air combat and air-to-surface attack. It provides a relatively low-cost, high-performance weapon system for the United States and allied nations.
In an air combat role, the F-16’s maneuverability and combat radius (distance it can fly to enter air combat, stay, fight and return) exceed that of all potential threat fighter aircraft. It can locate targets in all weather conditions and detect low flying aircraft in radar ground clutter. In an air-to-surface role, the F-16 can fly more than 500 miles (860 kilometers), deliver its weapons with superior accuracy, defend itself against enemy aircraft, and return to its starting point. An all-weather capability allows it to accurately deliver ordnance during non-visual bombing conditions.
The F-16 was built under an unusual agreement creating a consortium between the United States and four NATO countries: Belgium, Denmark, the Netherlands and Norway. These countries jointly produced with the United States an initial 348 F-16s for their air forces. Final airframe assembly lines were located in Belgium and the Netherlands. The consortium’s F-16s are assembled from components manufactured in all five countries. Belgium also provides final assembly of the F100 engine used in the European F-16s. The long-term benefits of this program will be technology transfer among the nations producing the F-16, and a common-use aircraft for NATO nations. This program increases the supply and availability of repair parts in Europe and improves the F-16’s combat readiness.
USAF F-16 multi-mission fighters were deployed to the Persian Gulf in 1991 in support of Operation Desert Storm, where more sorties were flown than with any other aircraft. These fighters were used to attack airfields, military production facilities, Scud missiles sites and a variety of other targets.
Originally conceived as a simple air-superiority day fighter, the aircraft was armed for that mission with a single six-barrel Vulcan 20-mm cannon and two Sidewinder missiles, one mounted at each wingtip. Over the years, however, the mission capability of the aircraft has been extended to include ground-attack and all-weather operations With full internal fuel, the aircraft can carry up to 12 000 pounds of external stores including various types of ordnance as well as fuel tanks.
The original F-16 was designed as a lightweight air-to-air day fighter. Air-to-ground responsibilities transformed the first production F-16s into multirole fighters. The empty weight of the Block 10 F-16A is 15,600 pounds. The empty weight of the Block 50 is 19,200 pounds. The A in F-16A refers to a Block 1 through 20 single-seat aircraft. The B in F-16B refers to the two-seat version. The letters C and D were substituted for A and B, respectively, beginning with Block 25. Block is an important term in tracing the F-16’s evolution. Basically, a block is a numerical milestone.The block number increases whenever a new production configuration for the F-16 is established. Not all F-16s within a given block are the same. They fall into a number of block subsets called miniblocks. These sub-block sets are denoted by capital letters following the block number (Block 15S, for example). From Block 30/32 on, a major block designation ending in 0 signifies a General Electric engine; one ending in 2 signifies a Pratt & Whitney engine.
The US Air Force took delivery of its last F-16 Fighting Falcon on March 18, 2005, the last of 2,231 F-16s produced for the Air Force. The first delivery was in 1978.
The air war experience in Vietnam, where the lack of maneuverability of US fighters at transonic speeds provided advantages to nimble enemy fighters, was the stimulus for the Lightweight Fighter program. The Air Force and designers of the Lightweight Fighter therefore placed great emphasis on achieving unprecedented transonic maneuver capability with excellent handling qualities.
In January 1972, the Lightweight Fighter Program solicited design specifications from several American manufacturers. Participants were told to tailor their specifications toward the goal of developing a true air superiority lightweight fighter. General Dynamics and Northrop were asked to build prototypes, which could be evaluated with no promise of a follow-on production contract. These were to be strictly technology demonstrators. The two contractors were given creative freedom to build their own vision of a lightweight air superiority fighter, with only a limited number of specified performance goals. Northrop produced the twin-engine YF-17, using breakthrough aerodynamic technologies and two high-thrust engines. General Dynamics countered with the compact YF-16, built around a single F100 engine.
The evolution of the YF-16 design at LMTAS included studies of configuration variables such as wing design, maneuvering devices, number and location of engines, control surfaces, number and location of tail surfaces, and structural concepts. As the configuration options matured, two candidate configurations competed for priority. The first configuration was a simple wing, body, and empennage design, while the second design was a twin-tailed, blended-wing body with vertical and horizontal tails on booms. The LMTAS team selected the best features of both configurations for the final YF-16 design. After considerations of performance, stability, and control were addressed, the YF-16 configuration incorporated a rather wide, blended forebody that produced strong vortices at moderate angles of attack. LMTAS had attempted to weaken the strength of the vortices by promoting attached flow, but these attempts were not successful.
In the early 1960’s worldwide interest in the phenomenon known as “vortex lift” increased as a result of aerodynamic studies of highly swept configurations such as the Concorde supersonic transport. The favorable effects of vortex on lift were demonstrated during development of the Swedish Viggen canard configured aircraft. The favorable effects of the canard trailing vortex on the lifting capability of a close-coupled wing might also be extended to higher angles of attack by the strong leading-edge vortex flow of a slender lifting surface. The leading edge of the blended forebody be sharpened to increase (rather than decrease) the strength of the vortices, which could be exploited for additional lift. This modification allowed the forebody vortices to dominate and stabilize the flow field over the aircraft at high angles of attack, improve longitudinal and directional stability for the single-tail configuration, and stabilize the flow over the outer wing panels. In addition, the sharpened strake significantly reduced buffet intensity at transonic maneuvering conditions. The wing-body strake of the F-16 is regarded as a key contribution to its success as a maneuvering fighter.
When the YF-16 team analyzed the effects of deflected leading- and trailing-edge flaps and the sharp-edged wing-body strake on directional stability at high angles of attack, they found that the stability contributions of a single vertical tail were significantly enhanced. However, the contributions of twin vertical tails were markedly degraded. As a result of this analysis, the YF-16 was configured with a single vertical tail. Thus, the Langley recommendation for a sharpened wing-body strake favorably impacted other configuration features of the aircraft.
Increased maneuverability for the YF-16 necessitated extended flight at high angles of attack where aerodynamic deficiencies caused by separated airflow can result in sudden decreases in stability and controllability. Therefore, special emphasis was placed on tests to insure that the YF-16 could provide the pilot with “care-free” maneuverability. To provide superior handling characteristics at high angles of attack, any undesirable handling characteristics were pushed out of the operating envelope of the aircraft and the flight envelope was limited with an advanced fly-by-wire flight control system by LMTAS. This concept has proven to be highly successful and has been used in all variants of the F-16.
Reliance on the flight control system to insure satisfactory behavior at high angles of attack required research on the ability of fly-by-wire control systems to limit certain flight parameters during strenuous air combat maneuvers. The F-16 employs the concept of “relaxed static stability” in which the aircraft is intentionally designed to be aerodynamically unstable while the flight control system provides integrated stability by sensing critical flight variables and making the control inputs required to stabilize the aircraft. Of particular concern was the ability of the horizontal tails and longitudinal control system to limit the aircraft’s angle of attack during maneuvers with high roll rates at low airspeeds. Such maneuvers are critical because rapid rolling maneuvers produce large nose-up trim changes due to inertial effects, whereas the aerodynamic effectiveness of the horizontal tails becomes significantly reduced at low airspeeds and high angles of attack.
Early on, tests of a YF-16 model indicated that if angle of attack was not limited by the flight control system, the aircraft could pitch up and attain an undesirable trimmed condition at very high angles of attack with insufficient nose-down aerodynamic control to recover normal flight. NASA Langley researchers viewed this “deep” stall as a serious problem that would require significant research for resolution. High-angle-of-attack test results obtained on models of the early production version of the F-16 configuration showed the same deep-stall trimmed condition that was noted in the YF-16 results. In subsequent high-angle-of-attack flight evaluations at Edwards Air Force Base, an F-16 that had been subjected to rapid rolls at diminishing airspeeds in vertical zoom climbs suddenly entered a stabilized deep-stall condition and the pilot was unable to recover the aircraft with normal aerodynamic controls. Fortunately, the test aircraft was equipped with an emergency spin recovery parachute that was deployed to recover the aircraft to normal flight conditions. This event brought all high-angle-of-attack flight tests of the F-16 to a stand-still while a solution to the deep stall could be found. The ultimate fix for the problem (which also improved takeoff performance) was increasing the size of the horizontal tail about 25 percent. This solution has been incorporated in all F-16 production aircraft.
When the Lightweight Fighter competition was completed early in 1975, both the YF-16 and the YF-17 showed great promise. The two prototypes performed so well, in fact, that both were selected for military service. On 13 January 1975 the Air Force announced that the YF-16’s performance had made it the winner of its Air Combat Fighter (ACF) competition. This marked a shift from the original intention to use the two airplanes strictly as technology demonstrators. General Dynamics’ YF-16 had generally shown superior performance over its rival from Northrop. At the same time, the shark-like fighter was judged to have production costs lower than expected, both for initial procurement and over the life cycle of the plane. At the same time, the YF-16 had proved the usefulness not only of fly-by-wire flight controls, but also such innovations as reclined seat backs and transparent head-up display (HUD) panels to facilitate high-G maneuvering, and the use of high profile, one-piece canopies to give pilots greater visibility. Thus, the Air Force had its lightweight fighter, the F-16.
In designing the F-16, advanced aerospace science and proven reliable systems from other aircraft such as the F-15 and F-111 were selected. These were combined to simplify the airplane and reduce its size, purchase price, maintenance costs and weight. The light weight of the fuselage is achieved without reducing its strength. With a full load of internal fuel, the F-16 can withstand up to nine G’s — nine times the force of gravity — which exceeds the capability of other current fighter aircraft.
The aerodynamic configuration of the F-16 is a highly integrated synthesis of such components as wing, fuselage, and inlet, with the aim of achieving maximum favorable flow interaction with subsequent optimization of overall performance. Configuration features include a cropped delta wing mounted near the top of the fuselage with large strakes extending forward from the leading edge to the sides of the fuselage. A single vertical tail is utilized together with a small fixed ventral fin located on the bottom of the fuselage. The all-moving horizontal tail is mounted in the low position and incorporates a small amount of negative dihedral.
A fixed-geometry, chin-mounted inlet supplies air to the single Pratt & Whitney F100-PW-200 turbofan engine, which is a variant of the same power plant utilized in the F-15. Since the forward portion of the fuselage provides some external flow compression, reasonable inlet efficiency is obtained even at a Mach number of 2.0. Good inlet efficiency through a wide range of angle of attack is ensured by the location of the inlet on the bottom side of the fuselage at a fore-and-aft location behind the forward intersection of the wing strakes with the side of the fuselage.
The cropped delta wing blends into the fuselage sides with large strakes that extend forward from the wing leading edges. Vortexes generated by these strakes help prevent wing stall at high angles of attack and thus increase the lifting capability of the wing. Leading-edge sweepback angle is 45° and the airfoil-section thickness ratio is 4 percent. Trailing-edge flaparons serve the double purpose of high-lift flaps and ailerons for lateral control. Leading-edge maneuvering flaps are deployed automatically as a function of Mach number and angle of attack.
In some respects, the control system of the F-16 represents a complete departure from previous fighter design practice. Although conventional-type aerodynamic control surfaces are employed, the control system utilizes a novel method of transmitting pilot commands to these surfaces. In previous fighter designs, some form of mechanical device linked the control stick and the rudder pedals to the hydraulic actuating system that moved the control surfaces. In contrast, the F-16 utilizes a fly-by-wire system in which movement of the pilot’s controls initiates electrical signals that activate the hydraulic systems and cause the control surfaces to be moved in a prescribed manner. The fly-by-wire system is lighter, simpler, and more precise than the older mechanical systems, but it does raise questions relating to electrical system reliability. In the F-16, redundancy is provided in the electrical generating and distribution equipment, and four dedicated sealed-cell batteries give transient electrical power protection for the fly-by-wire system. Two completely separate and independent hydraulic systems supply power for actuation of the aerodynamic control surfaces and other utility functions.
Another novel feature in the control system of the F-16 is the incorporation of “relaxed static stability.” This means that the inherent longitudinal stability is reduced, to a level traditionally thought to be unacceptable, by moving the aircraft center of gravity to a point very near the aerodynamic center of the aircraft. Tall load and associated trim drag are reduced by this process. Compensation for the loss in inherent aerodynamic stability is provided by a combination electronic-hydraulic stability augmentation system that senses uncalled-for departures from the intended flight condition and injects corrective signals into the flight control system.
The cockpit and its bubble canopy give the pilot unobstructed forward and upward vision, and greatly improved vision over the side and to the rear. The seat-back angle was expanded from the usual 13 degrees to 30 degrees, increasing pilot comfort and gravity force tolerance. The pilot has excellent flight control of the F-16 through its “fly-by-wire” system. Electrical wires relay commands, replacing the usual cables and linkage controls. For easy and accurate control of the aircraft during high G-force combat maneuvers, a side stick controller is used instead of the conventional center-mounted stick. Hand pressure on the side stick controller sends electrical signals to actuators of flight control surfaces such as ailerons and rudder. The arrangement of the pilot’s control stick is a radical departure from standards that trace their origin to the early days of World War I. Traditionally, the fighter pilot’s control stick used for actuation of the ailerons and elevators has consisted of a lever mounted on the floor of the cockpit between the pilot’s legs. (There have, of course been many variations in the detail design of the control stick.) On the F-16, the traditional control stick has been replaced by a short “side-arm controller” mounted on the right-hand console of the cockpit. The side-arm controller is a small-displacement pressure-sensitive handle that, together with the fly-by-wire system, gives the pilot the ability to exercise very precise control of the aircraft. To help prevent unwanted commands to the control handle the pilot rests his right arm in a carefully designed support.
Avionics systems include a highly accurate inertial navigation system in which a computer provides steering information to the pilot. The plane has UHF and VHF radios plus an instrument landing system. It also has a warning system and modular countermeasure pods to be used against airborne or surface electronic threats. The fuselage has space for additional avionics systems.
The Fiber Optic Towed Decoy (FOTD) provides aircraft protection against modern radar-guided missiles to supplement traditional radar jamming equipment. The device is towed at varying distances behind the aircraft while transmitting a signal like that of a threat radar. The missile will detect and lock onto the decoy rather than on the aircraft. This is achieved by making the decoy’s radiated signal stronger than that of the aircraft.