The NF-16D VISTA program was a rather interesting one to say the least. In 1991 they took an F-16D Block 30 (86-0048) and modified it into the
Variable-stability In-flight Simulator Test Aircraft, or VISTA, and later into the Multi-Axis Thrust Vectoring test aircraft (MATV).
For the VISTA program, a programmable center mounted control stick was added, as well as a larger hydraulic pump, and a custom designed variable
stability system controlled primarily by the back seater, although control could be shifted to the front seat by the rear seat controls.
Modifications for the MATV program included an Axisymmetric Vectoring Exhaust Nozzle (AVEN) thrust vectoring system (AVEN moves a ring in the exhaust
nozzle to achieve thrust vectoring and can be retrofitted on any F110 powered F-16 with a digital flight control system), 700 pounds of ballast, and a
spin recovery parachute. Interestingly the AVEN engine nozzle pushes the exhaust around, instead of moving the entire nozzle. This keeps air from
coming back into the engine, and shifts the pressure of the movement back to the engine instead of the airframe.
Because of the center and side mounted stick in the front cockpit, the aircraft can be configured to fly like a delta wing aircraft, to simulate
canards, or like a large cargo aircraft.
With the thrust vectoring installed, the aircraft is able to hold an 86 degree angle of attack, and a transitory 180 degree angle of attack, allowing
it to perform maneuvers such as the Cobra. The aircraft was tested in both 1v1 and 1v2 with other F-16s and with the MATV system was able to
outmaneuver the other aircraft quite well, and hold its own.
The modifications for the VISTA program were completed in 1992, and the first flight was made in April of that year. Shortly afterwards funds were
withdrawn. Some features of the VISTA program were removed for the MATV testing, and the F110 engine was replaced with the AVEN nozzle engine.
The program was considered very successful, and was promptly shuttered with very little of it to be seen again. The program was also responsible for
the virtual HUD, and direct voice input, both of which, along with some of the MATV technology, are in use on the F-35.
After the program ended, the modifications were left largely in place, and 0048 was transferred to the Air Force Test Pilot School where it can be
seen to this day. It's still used in the student curriculum and for some test flights.
Sorry, Boomer, you are thinking of the F-16XL with the cranked-arrow delta wing. If it had gone into production, it would have been the F-16E. The two
prototypes ended up with NASA and were used for a variety of research projects until their retirement. They both belong to the National Museum of the
U.S Air Force now, and the single-seater is currently on display in the Air Force Flight Test Museum at Edwards.
The AF Test Pilot School students still use the NF-16D VISTA for class projects.