Cessna A-37 Dragonfly
Operational History

In August 1967, 25 of the A-37As were sent to Vietnam under the "Combat Dragon" evaluation program, and flew from Bien Hoa Air Force Base on USAF "air commando" missions, including close air support, helicopter escort, FAC, and night interdiction. Warloads included high-explosive bombs, cluster munition dispensers, unguided rocket packs, napalm tanks, and the SUU-11/A Minigun pod. For most missions, the aircraft also carried two additional external tanks on the inner stores pylons.

The A-37As flew thousands of sorties. None were lost to enemy fire, though two were wrecked in landing accidents. The A-37A was formally named the "Dragonfly", but most pilots called it the "Super Tweet." The Combat Dragon program was successful, but unsurprisingly the combat evaluation revealed some of the deficiencies of the A-37A. The most noticeable problem was that the aircraft lacked range and endurance. Other concerns were heavy control response during attack runs (the flight controls were not power-boosted) and the vulnerability of the aircraft's non-redundant flight control system.

The USAF signed a contract with Cessna in early 1967 for an improved Super Tweet, designated the "A-37B". The initial order was for 57 aircraft, but this was quickly increased to 127. The A-37Bs were primarily intended to be supplied to the VNAF South Vietnamese Air Force as replacements for their Skyraiders. The A-37B prototype was rolled out in September 1967, with deliveries to the South Vietnamese beginning in 1968.

The A-37Bs were all newly built airframes. These were stronger than those of the A-37A, capable of pulling 6 g instead of 5, and were built to have a longer fatigue life of 4,000 hours. Field experience would demonstrate that 7,000 hours between overhauls could be tolerated.

The A-37B weighed almost twice as much as the T-37C. A remarkable fraction of the loaded weight, 2.67 tonnes (5,880 lb), could be comprised of external stores. In practice, the A-37B usually operated with at least two and sometimes four underwing fuel tanks to improve combat endurance.

To get this increased weight off the ground, the A-37B was fitted with General Electric J85-GE-17A engines, providing 12.7 kN (2,850 lbf) thrust each. These engines were canted slightly outward and downward to improve single-engine handling. Air commando pilots in Vietnam operating the A-37A had found single-engine cruise an effective means of improving their flight endurance.

Modifications were made to control surfaces to improve handling. To improve aircraft and crew survivability, the A-37B was fitted with redundant elevator control runs that were placed as far apart as possible. The ejection seats were armored, the cockpit was lined with nylon flak curtains, and foam-filled self-sealing fuel tanks were installed.

The A-37B added a refueling probe to the nose, leading to pipes wrapped around the lower lip of the canopy, for probe-and-drogue aerial refueling. This was an unusual fit for USAF aircraft, which traditionally are configured for boom refueling. Other improvements included updated avionics, a redesigned instrument panel to make the aircraft easier to fly from either seat, an automatic engine inlet de-icing system, and revised landing gear. Like its predecessors, the A-37B was not pressurized.

The 20mm GPU-2/A and AMD 30mm cannon pods were tested with favorable results on the A-37B to give it more punch, but reports indicate that such pods were rarely or never used in operation.

A total of 577 A-37Bs were built, with 254 delivered to the South Vietnamese Air Force. They reportedly performed well in actions against Communist forces. Before South Vietnam fell in early April 1975, a South Vietnamese Air Force officer, Captain Nguyen Thanh Trung, defected to the Communists in his F-5E and then led strikes against South Vietnamese government positions, with NVAF pilots flying in two squadron of A-37B based at Phuoc Long airbase.

There were about 187 A-37Bs in South Vietnamese hands when the country fell. Ninety-two were recovered by the Americans, while the other 95 were later used by the Communist Vietnamese in missions over Cambodia and during the China conflict in 1979. These "renegade" aircraft were phased out of service in the late 1970s or early 1980s, in all probability due to lack of spares. Some of the aircraft were shipped to Vietnam's allies like Poland, the Soviet Union, and East Germany. Others were sold to private foreign owners, 6 of A-37B became property of American Warbird fans, 4 of A-37Bs are now privately-owned in Australia and New Zealand.

After the war, the USAF passed their A-37Bs from the USAF Tactical Air Command to Air National Guard and Air Force Reserve units. In the early 1980s these aircraft were assigned the FAC role and given the designation OA-37B. The OA-37Bs were eventually phased out and replaced in the FAC mission by the much more formidable Fairchild OA-10A Warthog.

The A-37B was also exported to Latin America, mostly during the 1970s. It was well suited to their needs because of its simplicity, low cost, and effectiveness for insurgent warfare. Most of the A-37Bs exported south had the refueling probe shortened to act as a single-point ground refueling probe, or deleted completely.

Wikipedia: A-37 Dragonfly