Power was served through 2 x Pratt & Whitney R-1830 series air-cooled, radial piston engines developing 1,200 horsepower each. Coupled with the airframe's design, this allowed for a maximum airspeed of 230 miles per hour, a cruise speed nearing 175 miles per hour, a range out to 2,175 miles, and a service ceiling of 24,450 feet.
Testing of AC-47 aircraft in the Vietnam theater began in late 1964 and continued into early 1965 with success. The 4th Commando Squadron was then established in August 1965 to become its first formal operator. AC-47 gunships were pressed into service as convoy escorts/general strike and Forward Air Control (FAC) during daylight hours and as CAS platforms during low-light, nighttime hours - including illumination of enemy positions. In the latter, flares were dropped manually from the rear cargo door after a signal was delivered from the pilot in the cockpit. To ground troops, the aircraft became known as "Puff" or "Puff the Magic Dragon" for its ferocious portside lethality on unprotected enemies. AC-47s were later passed on to the South Vietnamese Air Force during "Vietnamization" in the U.S. drawdown of combat actions in the region.
Of note is that base C-47 transports arrived in the theater during earlier in February 1962 though these were strictly used on illumination runs - these aircraft known as "flareships".
Of the 53 AC-47s delivered, about 41 of this inventory saw combat service in the Vietnam War. Some twelve were lost to combat reason while nineteen airframes were lost in all - proving the aircraft was not invulnerable to all manner of battlefield dangers. It was slow and poorly protected which made for disastrous results in some cases. The AC-47 - forgotten by many in today's technology-laden world of military hardware - was a potent platform to the extreme - a life-saver to some and a life-taker to her enemies. Despite their age, some air forces continue their operation from ex-USAF stocks, this being Colombia and El Salvador for counter-insurgency work. They have been outfitted for the carrying of conventional drop ordnance and feature modern implements such as FLIR (Forward-Looking InfraRed).
Former operators beyond the United States have become Cambodia, Indonesia, Laos, Philippines, Rhodesia, South Africa, South Vietnam, and Thailand.
U.S. forces in Vietnam operated AC-47s through 3d Air Commando Squadron (from 1968 to 1969), the 4th Air Commando Squadron (from 1964 to 1969) and the 5th Air Commando Squadron of the 14th Special Operations Wing. From August 1968, their names were revised from "Air Commando" to "Special Operations".
Action reports concerning these early American gunships proved critical in the upcoming C-130 ("Gunship II") and the subsequent Fairchild C-119 ("Gunship III") conversion programs.