Douglas AC-47D

An interim version of the Douglas AC-47D equipped with 10 .30-cal. machine guns — two in each of the windows forward of the passenger door, two in the passenger door and four in the cargo door (aft of the passenger door). This aircraft is probably S/N 43-48991 “Git-em Bullett” of the 4th ACS. (U.S. Air Force photo)

 

In the early 1960s, Air Force Systems Command began experimenting with side-firing weapons systems for possible use in Vietnam in point defense and night Close Air Support (CAS) roles. In late 1964, the first gunship conversion of a World War II Douglas C-47D was done. The gunship version of the C-47D was initially designated FC-47D (Fighter-Cargo), but was changed to AC (Attack Cargo) primarily because of complaints by traditional fighter pilots. The aircraft had several nicknames: “Spooky,” “Puff the Magic Dragon” and “Puff.”

 

The AC-47D(S/N 43-48579) was equipped with three SUU-11A 7.62mm “miniguns” with a 6,000 round per minute rate of fire. The miniguns were mounted in the aft left fuselage. One gun was installed in the aft passenger door area; the other two guns were mounted just forward of the passenger door with the gun barrels pointed out window ports. The AC-47D carried about 16,500 rounds of ammunition on a typical mission.

 

For night missions, the aircraft carried approximately 48 MK-24 flares. Each flare would last up to three minutes (Mod 3 version) and produced a light of 2 million candlepower. The delivery system was extremely simple: the loadmaster armed and dropped the flare out the cargo door when the pilot signaled by flashing a cargo compartment light.

 

AC-47 Operations Bulletin #56 – 13 Feb 67 (PACAF)

As employed in Southeast Asia, the flight crew consisted of seven USAF personnel, as well as a Vietnamese observer assigned to aid in the “delta” missions. The aircraft commander (pilot) fired the gun while the co-pilot performed the normal piloting duties and coordinated the activities of the crew. In the target area the navigator and Vietnamese Air Force observer (eighth crewman if assigned) collaborated to accurately pinpoint objectives and coordinate with the ground forces. Two gunners accomplish the preflight, gun loading and in-flight troubleshooting of the SUU-11 guns. The loadmaster armed and manually dropped the flares from the rear entrance door upon a light signal from the aircraft commander. A flight mechanic rounded out the crew and was responsible for aircraft systems operation.

 

The basic missions on which the AC-47 was employed were:

 

1. Defense of ground positions (friendly forts and outposts)

2. Escort and patrol

3. Pre-planned strikes against suitable targets

4. Forward air controlling for fighter strikes

 

Initial attack procedures began with the aircraft in straight and level flight, and the target just outside and forward of the left prop dome. Usual altitude is between 2,500-3,000 feet above ground level (AGL); however, this could be adjusted to allow for such variables as weather, ground fire and target identification difficulties. As the target passed under the engine cowling, the aircraft was rolled into a level 30 degree bank turn. When the (gun site) pipper came on target, firing was commenced in bursts of 3-7 seconds, as required. When the pipper moved off the target to the rear, the firing was ceased and a slight turn was made away from the target for repositioning and subsequent firing passes. If the pipper moved off the target to the front, the degree of bank was increased to realign on target. Airspeed during the maneuver was normally 120 knots indicated air speed (KIAS). Each minigun fired at a rate of 6000 rounds per minute. This provided coverage over an elliptical area approximately 52 yards in diameter, placing a projectile within every 2.4 yards during a 3 second burst.

 

The guns were configured for a 12 degree declination to allow shallower bank angles and more precise aircraft control.

 

Combat Use of the AC-47

The combat use of the C-47 in Vietnam began in February 1962 when the aircraft was used to drop flares to illuminate outposts and small villages under night attack by Viet Cong forces. These C-47 flareships were based at Bien Hoa Air Base and were part of the Operation Farmgate (initially Jungle Jim) program to train VNAF forces in counterinsurgency operations.

 

When Operation Farmgate ended on July 28, 1963, the C-47 flareships were transferred to the 1st Air Commando Squadron at Bien Hoa Air Base. The first test use of the AC-47 gunship (initially FC-47) in combat occurred on Dec. 15, 1964, with testing continued into early 1965. One early and significant success happened on the night of Dec 23-24, 1964. The AC-47 defended a small outpost at Tranh Yend just 37 minutes after the request was issued. The “Spooky” fired 4,500 rounds of ammunition and broke the Viet Cong attack, forcing a retreat. The AC-47 was then called to defend another outpost (Trung Hung) about 20 miles away. The aircraft again broke the VC attack forcing a retreat.

 

The AC-47D combat test program was very successful and the Air Force created the 4th Air Commando Squadron in August 1965 as the first operational unit equipped with the “Spooky” gunship. Although the 4th ACS was based at Tan Son Nhut Air Base, it operated several forward operating locations throughout South Vietnam (Bien Hoa, Pleiku, Na Trang, Da Nang and Can Tho). In November 1965, the 4th ACS was assigned 16 operational aircraft with four more assigned as “advanced attrition” aircraft. Because of a shortage of SUU-11A gun pods, the AC-47Ds were fitted with only two miniguns rather than three. A few aircraft were temporarily fitted with 8 or 10 .30-cal. M2 machine guns, but all were later refitted with miniguns. By early 1966, production of the minigun increased so each of the 16 AC-47Ds was equipped with all three guns.

 

With the success of the AC-47 gunship, two more squadrons were created: the 3rd and 5th ACS, all under the 14th Air Commando Wing. In August 1968, the unit designations were changed from Air Commando to Special Operations.

 

The USAF converted 53 C-47s for use as gunships during the Vietnam War. Although the AC-47 was an effective attack system, it was also vulnerable to enemy fire. Fifteen aircraft were lost between Dec. 17, 1965, when the first AC-47 was lost due to ground fire and Sept. 5, 1969, when an VNAF AC-47D crashed due to pilot error. In 1969 the USAF turned over its AC-47Ds to the VNAF under the “Vietnamization” program.

 

The lessons learned with the AC-47D Gunship I program were used to design an improved version in the Gunship II program using the Lockheed C-130 as the base platform. Later, the Gunship III program converted Fairchild C-119s into side-firing gunships.

 

Although the museum does not have an AC-47D on display, a C-47D is on display in the Air Power Gallery.

 

 

Type                 Number built/

converted                 Remarks

AC-47D                 53                 Gunship version of C-47

 

 

TECHNICAL NOTES:

Armament: Three SUU-11A 7.62mm miniguns firing at up to 6,000 rpm. The AC-47D typically carried about 16,500 rounds of ammunition. Note: Three aircraft initially equipped with 8 or 10 .30-cal. machine guns and others had just two SUU-11A miniguns (due to lack of availability from the manufacturer). Later, the SUU-11As were replaced by specially designed General Electric MXU-470/A 7.62mm miniguns. 48 MK-24 Mod 3 flares with 2 million candlepower and a 3-minute maximum burn duration. Note: Initially (in 1964 and early 1965) 30 MK-6 flares of 750,000 candlepower were carried before the MK-24 flares were available. Later in the war, several replacements for the MK-24 flares were proposed including the MK-33 one million candlepower rocket and MLU-32/B99 “Briteye” 5 million candlepower flare

Engines: Two Pratt & Whitney R-1830s of 1,200 hp each

Maximum speed: 232 mph

Cruising speed: 175 mph

Attack speed: 120 knots

Combat duration: 7 hours maximum, although a typical combat mission was about 5 or 6 hours maximum

Span: 95 ft. 0 in.

Length: 64 ft. 5 in.

Height: 16 ft. 11 in.

Weight: 33,000 lbs. loaded

Service ceiling: 24,450 ft.

Crew: 7-8 (pilot, copilot, navigator, flight engineer, loadmaster, two gunners and a South Vietnamese observer)

Serial numbers: (not all serial numbers are listed, as no complete list is currently available) 43-16065, 43-16159, 43-48072, 43-48263, 43-48356, 43-48462, 43-48466, 43-48491, 43-48501, 43-48579, 43-48591, 43-48686, 43-48701, 43-48801, 43-48916, 43-48921, 43-48925*, 43-49021, 43-49124, 43-49211, 43-49268*, 43-49274, 43-49330, 43-49339, 43-49421, 43-49492*, 43-49499, 43-49502, 43-49517, 43-49546, 43-49852, 44-76207, 44-76290*, 44-76370, 44-76394, 44-76534, 44-76542, 44-76593, 44-76606, 44-76722, 44-77263, 45-00919, 45-00927, 45-01057, 45-01117, 45-01120*, 45-01121 (*Attrited Aircraft)

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