An F-16XL refuels in-flight. Only two XLs were built, and NASA eventually operated both for experimental purposes, including an active supersonic laminar flow experiment.

The single-seat F-16XL, NASA 849, joins up with an SR-71A, NASA 844, as crews set up for one of the flights in the recent sonic boom research program conducted by the Dryden Flight Research Center, Edwards, California. During the missions, the F-16XL probed the shockwaves generated by the SR-71, while at lower altitudes sensors on an F-18 and on a YO-3A, and also on the ground, recorded data from the same shockwave.

Four different versions of the F-16 were used by Dryden in the 1990s. On the left and right sides are two F-16XLs. On the left is the F-16XL #2 (NASA 848), which is the two-seat version, used for advanced laminar flow studies until late 1996. On the right is the single-seat F-16XL #1 (NASA 849), used for laminar flow research and sonic boom research. (Laminar flow refers to smooth airflow over a wing, which increases lift and reduces drag compared to turbulent airflow). Between them at center left is an F-16A (NASA 816), the only civilian operated F-16. Next to it at center right is the U.S. Air Force Advance Fighter Technology Integration (AFTI) F-16, a program to test new sensor and control technologies for future fighter aircraft. Both F-16XLs are in storage at Dryden. The F-16A was never flown at Dryden, and was parked by the entrance to the center. The AFTI F-16 is in the Air Force Museum.

NASA Dryden flight test engineer Marta Bohn-Meyer is suited up for a research flight in the F-16XL laminar-flow control experiment in this 1993 photo.

The single-seat F-16XL, NASA 849, joins up with an SR-71A, NASA 844, as crews set up for one of the flights in the recent sonic boom research program conducted by the Dryden Flight Research Center, Edwards, California. During the missions, the F-16XL probed the shockwaves generated by the SR-71, while at lower altitudes sensors on an F-18 and on a YO-3A, and also on the ground, recorded data from the same shockwave.

The single-seat F-16XL, NASA 849, joins up with an SR-71A, NASA 844, as crews set up for one of the flights in the recent sonic boom research program conducted by the Dryden Flight Research Center, Edwards, California. During the missions, the F-16XL probed the shockwaves generated by the SR-71, while at lower altitudes sensors on an F-18 and on a YO-3A, and also on the ground, recorded data from the same shockwave.

NASA's single-seat F-16XL makes a drag chute landing on the runway at Edwards Air Force Base in California's Mojave Desert. The aircraft was most recently used in the Cranked-Arrow Wing Aerodynamics Project (CAWAP) to test boundary layer pressures and distribution. Previously it had been used in a program to investigate the characteristics of sonic booms for NASA's High Speed Research Program. Data from the program will be used in the development of a high speed civilian transport. During the series of sonic boom research flights, the F-16XL was used to probe the shock waves being generated by a NASA SR-71 and record their shape and intensity.

Apollo 11 astronaut Buzz Aldrin autographs NASA Dryden's F-16XL research aircraft, as his crewmate Neil Armstrong had previously done on the other side.

The support crew for the F-16A, the F-16XL no. 1, and the F-16 AFTI are, top row, left to right: Randy Weaver; mechanic, Susan Ligon; mechanic, Bob Garcia; Crew Chief, Rich Kelly; mechanic, Dale Edminister; Avionics Technician. Bottom row, left to right, Art Cope; mechanic, John Huffman; Avionics Technician, Jaime Garcia; Avionics Technician, Don Griffith, Avionics Tech. Co-op student. The F-16A (NASA 516), the only civil registered F-16 in existence, was transferred to Dryden from Langley, and was primarily used in engine tests and for parts. It was subsequently transfered from Dryden. The single-seat F-16XL no. 1 (NASA 849) was most recently used in the Cranked-Arrow Wing Aerodynamics Project (CAWAP) to test boundary layer pressures and distribution. Previously it had been used in a program to investigate the characteristics of sonic booms for NASA's High Speed Research Program. Data from the program will be used in the development of a high speed civilian transport. During the series of sonic boom research flights, the F-16XL was used to probe the shock waves being generated by a NASA SR-71 and record their shape and intensity. The Advanced Fighter Technology Integration (AFTI) F-16 was used to develop and demonstrate technologies to improve navigation and a pilot's ability to find and destroy enemy ground targets day or night, including adverse weather. Earlier research in the joint NASA-Air Force AFTI F-16 program demonstrated voice actuated controls, helmet-mounted sighting and integration of forward-mounted canards with the standard flight control system to achieve uncoupled flight.

The support crew for the F-16A, the F-16XL no. 1, and the F-16 AFTI are, top row, left to right: Randy Weaver; mechanic, Susan Ligon; mechanic, Bob Garcia; Crew Chief, Rich Kelly; mechanic, Dale Edminister; Avionics Technician. Bottom row, left to right, Art Cope; mechanic, John Huffman; Avionics Technician, Jaime Garcia; Avionics Technician, Don Griffith, Avionics Tech. Co-op student. The F-16A (NASA 516), the only civil registered F-16 in existence, was transferred to Dryden from Langley, and was primarily used in engine tests and for parts. It was subsequently transfered from Dryden. The single-seat F-16XL no. 1 (NASA 849) was most recently used in the Cranked-Arrow Wing Aerodynamics Project (CAWAP) to test boundary layer pressures and distribution. Previously it had been used in a program to investigate the characteristics of sonic booms for NASA's High Speed Research Program. Data from the program will be used in the development of a high speed civilian transport. During the series of sonic boom research flights, the F-16XL was used to probe the shock waves being generated by a NASA SR-71 and record their shape and intensity. The Advanced Fighter Technology Integration (AFTI) F-16 was used to develop and demonstrate technologies to improve navigation and a pilot's ability to find and destroy enemy ground targets day or night, including adverse weather. Earlier research in the joint NASA-Air Force AFTI F-16 program demonstrated voice actuated controls, helmet-mounted sighting and integration of forward-mounted canards with the standard flight control system to achieve uncoupled flight.

NASA's single-seat F-16XL makes a drag chute landing at the Dryden Flight Research Center, Edwards, California. The aircraft was most recently used in the Cranked-Arrow Wing Aerodynamics Project (CAWAP) to test boundary layer pressures and distribution. Previously it had been used in a program to investigate the characteristics of sonic booms for NASA's High Speed Research Program. Data from the program will be used in the development of a high speed civilian transport. During the series of sonic boom research flights, the F-16XL was used to probe the shock waves being generated by a NASA SR-71 and record their shape and intensity.

An image of the F-16XL #1 during its functional flight check of the Digital Flight Control System (DFCS) on December 16, 1997. The mission was flown by NASA research pilot Dana Purifoy, and lasted 1 hour and 25 minutes. The tests included pilot familiarly, functional check, and handling qualities evaluation maneuvers to a speed of Mach 0.6 and 300 knots. Purifoy completed all the briefed data points with no problems, and reported that the DFCS handled as well, if not better than the analog computer system that it replaced.

Photographed outside their hangar at the Dryden Flight Research Center, Edwards, California, part of Dryden's F-16 fleet is, left to right; an F-16A, the F-16XL no. 1, and the F-16 AFTI. The F-16A (NASA 516), the only civil registered F-16 in existence, was transferred to Dryden from Langley, and was primarily used in engine tests and for parts. It was subsequently transfered from Dryden. The single-seat F-16XL no. 1 (NASA 849) was most recently used in the Cranked-Arrow Wing Aerodynamics Project (CAWAP) to test boundary layer pressures and distribution. Previously it had been used in a program to investigate the characteristics of sonic booms for NASA's High Speed Research Program. Data from the program will be used in the development of a high speed civilian transport. During the series of sonic boom research flights, the F-16XL was used to probe the shock waves being generated by a NASA SR-71 and record their shape and intensity. The Advanced Fighter Technology Integration (AFTI) F-16 was used to develop and demonstrate technologies to improve navigation and a pilot's ability to find and destroy enemy ground targets day or night, including adverse weather. Earlier research in the joint NASA-Air Force AFTI F-16 program demonstrated voice actuated controls, helmet-mounted sighting and integration of forward-mounted canards with the standard flight control system to achieve uncoupled flight.

The F-16XL #1 (NASA 849) takes off for the first flight of the Digital Flight Control System (DFCS) on December 16, 1997. Like most first flight, the DFCS required months of preparations. During July 1997, crews worked on the engine, cockpit, canopy, seat, and instrumentation. By late August, the aircraft began combined systems tests and a flight readiness review. Although the Air Force Safety Review Board (AFSRB)- a group that provided double checks on all flight operations - approved the program in late November 1997, a problem with the aircraft flight computer delayed the functional check flight until mid-December.

A collection of NASA's research aircraft on the ramp at the Dryden Flight Research Center in July 1997: X-31, F-15 ACTIVE, SR-71, F-106, F-16XL Ship #2, X-38, Radio Controlled Mothership and X-36.

NASA 834, an F-14 Navy Tomcat, seen here in flight, was used at Dryden in 1986 and 1987 in a program known as the Variable-Sweep Transition Flight Experiment (VSTFE). This program explored laminar flow on variable sweep aircraft at high subsonic speeds. An F-14 aircraft was chosen as the carrier vehicle for the VSTFE program primarily because of its variable-sweep capability, Mach and Reynolds number capability, availability, and favorable wing pressure distribution. The variable sweep outer-panels of the F-14 aircraft were modified with natural laminar flow gloves to provide not only smooth surfaces but also airfoils that can produce a wide range of pressure distributions for which transition location can be determined at various flight conditions and sweep angles. Glove I, seen here installed on the upper surface of the left wing, was a "cleanup" or smoothing of the basic F-14 wing, while Glove II was designed to provide specific pressure distributions at Mach 0.7. Laminar flow research continued at Dryden with a research program on the NASA 848 F-16XL, a laminar flow experiment involving a wing-mounted panel with millions of tiny laser cut holes drawing off turbulent boundary layer air with a suction pump.

NASA 834, an F-14 Navy Tomcat, seen here in flight, was used at Dryden in 1986 and 1987 in a program known as the Variable-Sweep Transition Flight Experiment (VSTFE). This program explored laminar flow on variable sweep aircraft at high subsonic speeds. An F-14 aircraft was chosen as the carrier vehicle for the VSTFE program primarily because of its variable-sweep capability, Mach and Reynolds number capability, availability, and favorable wing pressure distribution. The variable sweep outer-panels of the F-14 aircraft were modified with natural laminar flow gloves to provide not only smooth surfaces but also airfoils that can produce a wide range of pressure distributions for which transition location can be determined at various flight conditions and sweep angles. Glove I, seen here installed on the upper surface of the left wing, was a "cleanup" or smoothing of the basic F-14 wing, while Glove II was designed to provide specific pressure distributions at Mach 0.7. Laminar flow research continued at Dryden with a research program on the NASA 848 F-16XL, a laminar flow experiment involving a wing-mounted panel with millions of tiny laser cut holes drawing off turbulent boundary layer air with a suction pump.

Dryden Flight Research Center - aircraft fleet on ramp