YF-117 Nighthawk (79-10784) Tags

Developed by the Skunk Works in 1970s, the F-117 Nighthawk was the World’s very first stealth aircraft that entered active service in an air force.

The YF-117, serial number 79-10784, was the fifth and final prototype of the F-117. When the first two prototypes—79-10780 (Scorpion 1) and 79-10781 (Scorpion 2)—were retired early in 1992 and 1991 respectively, the remaining three full-scale development aircraft continued trials well into the early 2000s. The 79-10784 featured in this FIGHTERTAGS release was one of them!

Among all YF-117 prototypes and production F-117s, #784 was unique in many ways. It was the only airframe ever fitted with a B-1 PESA radar system in late 1985 and was used for flight tests involving the GBU-31 Joint Direct Attack Munition in 2004.

The most fascinating project involving 79-10784 took place in 1993, when the aircraft was selected to participate in a highly secret program called Senior Spud. Assigned to the 410th Test Squadron at Edwards AFB, the aluminum skin on the left half of #784 was coated with a mirror-like reflective material to evaluate methods for reducing its infrared signature. Beginning in July 1993, it completed four test flights, including low passes over the main runway at Edwards AFB, during which its infrared signature was measured by sensors onboard the NKC-135A Flying Infrared Signature Technology Aircraft (FISTA).

While the test results remain classified, the reflective coating was observed to dramatically increase the aircraft’s visual signature under sunlight, making it appear to “light up” on bright days. Despite this, the coating likely achieved its purpose of reducing the IR signature, as a similar mirror-like treatment was later tested on an F-22 Raptor in late 2021.

Several tags in this FIGHTERTAGS release were cut from the fuselage skin bearing this highly secret mirror-like coating that was applied to #784 during the Senior Spud project.