Fairchild AC-119 Shadow/Stinger
Design & Development

By late 1967, the idea of the fixed-wing gunship had been proven so successful that the United States Air Force was having a difficult time keeping up with demand. The newer AC-130s that had been created under Project Gunship II were effective, but were being mostly used for interdiction of the Ho Chi Minh Trail. Furthermore, the C-130 airframe was in active service as a transport, vital to the war effort in South East Asia. The Air Force desperately needed a new gunship to replace the vulnerable and underpowered AC-47 in supporting "Troops In Contact" (known as TIC), as well as, supplementing the AC-130 in attacking targets on the Ho Chi Minh Trail.

The C-119 Flying Boxcar presented an obvious choice, having been phased out of frontline service in favor of the C-123 and C-130, and with the stock of available airframes in U.S. Air Force Reserve being sufficient. In February 1968, under the USAF program Project Gunship III, 26 C-119Gs were converted to AC-119G standard, initially taking on the name "Creep," but later assigned the callsign "Shadow." These aircraft were primarily intended to replace the AC-47 in the TIC role. In addition, Fairchild-Hiller, which was contracted for all the conversions, converted 26 C-119Ks into AC-119Ks primarily for the "truck hunter" role over the Ho Chi Minh Trail. These aircraft were called "Stingers" primarily in reference to the two M61 Vulcan 20 mm cannons they carried in addition to the AC-119G's four GAU-2/A miniguns.

Project Gunship III, being a follow on to the success of the AC-130 series, meant that the AC-119 was a far more advanced aircraft in both its iterations than the AC-47. Even the TIC AC-119G featured some of the most up-to-date ECM and radar equipment, as well as more basic technology including an AVQ-8 Xenon light, a Night Observation Sight (NOS) and an LAU-74/A flare launcher.

The AC-119K, designed to hit trucks on the Ho Chi Minh Trail, was significantly more advanced. Included in the conversion was the AN/APN-147 Doppler Navigation radar, AN/AAD-4 Forward Looking Infrared (FLIR), AN/APQ-133 side-looking beacon tracking radar and AN/APQ-136 search radar.

The armament scheme for both aircraft was significantly simpler than that of the AC-130. The AC-119G had a total of four GAU-2A/A miniguns in SUU-11A/A pods, all on mounts similar to those used on early AC-47s. Like late model AC-47s, these were soon changed to the purpose-built MXU-470/A minigun modules. The AC-119K, needing a more powerful and longer range "punch" to take out vehicles, featured two M61 20 mm cannons in addition to the four Miniguns of the AC-119G.

Wikipedia: AC-119 Shadow/Stinger