A-37 Dragonfly

The Cessna A-37 Dragonfly earned a reputation as one of the most effective close-support and counter-insurgency aircraft of the Vietnam war.

From a small jet trainer, the “Super Tweet” was transformed into a heavily armed CAS aircraft capable of carrying thousands of pounds of weapons. When the first A-37s arrived in Vietnam for the experimental Combat Dragon program, their crews were about to discover just how capable the little aircraft really was.

Flying thousands of sorties in some of the war’s most dangerous low-level missions, the Dragonfly proved remarkably accurate, rugged and reliable. Yet despite its extraordinary combat record, it remained largely overshadowed by aircraft like the F-4 Phantom and A-1 Skyraider. We think the A-37 Dragonfly was one of the most underrated attack aircraft of the Vietnam War.

 

Fighting irregular forces has become a core part of modern warfare. Many conflicts today feature some counterinsurgency element. During the 1950s, new compact technology, communications, weapons, and training from the Eastern Bloc allowed small militias to fight on a more even footing with big armies. As the Dutch and French soon found out, these new tactics were extremely effective. By the Vietnam War, insurgency and counterinsurgency doctrine was maturing and formed the entire basis for the Viet Cong.

The role of air power in counterinsurgency soon gained prominence; one pioneer on the modern battlefield was the A-37 Dragonfly, or Super Tweet. Unfortunately overlooked at the time, it was an unsung hero, flying missions ranging from convoy strikes to troop support.

BACKGROUND

One of the biggest military issues of the 1950s was the rise of modern guerrilla warfare. From North Africa to East Asia, European powers – namely the French, British, and Dutch – found themselves bogged down in guerrilla conflicts. New, unconventional tactics, smaller, more reliable weaponry, and better decentralised command and control systems meant smaller armies or militias could fight bigger adversaries more effectively.

The increasing frequency of these conflicts had highlighted several crucial gaps—some of them in the realm of air power. Since the end of World War 2, most air forces had pivoted away from small, slow, agile designs. At the time, the US Air Force had handed air-to-ground tasking to larger, faster platforms like the Hun.

By 1960, however, the prospect of a counter-insurgency conflict involving American forces had grown. The Eastern Bloc had seen considerable success in developing nations; the most immediate threats were in South and Central America, although larger-scale militia wars were flaring up in Africa and East Asia. In almost all cases, the conflicts were either predicted to be guerrilla wars or already were.

In 1962, both the US Air Force and the Army began reviewing ideas for a counterinsurgency (COIN) aircraft. Unlike existing planes retrofitted for the role, such as the A-1 Skyraider or T-28 Trojan, a dedicated COIN platform would be built around a small airframe, able to fly low and conduct long sorties over enemy territory. Once on station, it would need to be ready for dynamic engagements, with good mission endurance for loitering and a large assortment of weapons on hand.

The Army – despite being limited in fixed-wing operations – evaluated several existing designs for conversion, including the Skyhawk, Fiat G.91, and a Northrop N-156F (precursor to the F-5 Freedom Fighter). However, the most promising for an armed, reliable, and lightweight platform was the T-37 Tweet trainer, built by Cessna.

While an Army acquisition was barred, during the same period in late 1962, a proper review of the Tweet was conducted under the Special Air Warfare Centre at Eglin. Similar to the Army, the Air Force saw potential in adapting its methods to meet COIN standards. It was small, reliable, and easy to maintain, and it would be familiar to younger pilots who had trained on the type—something that couldn’t be said for more archaic and dangerous designs like the Skyraider.

In 1963, the USAF awarded Cessna the contract for two YAT-37D prototypes, the first of which flew on 22 October. The modifications would be extensive; the aircraft would need to be capable of short-field operations, with armour protection, improved engines, longer loiter time, and compatibility with a variety of modern weapons.

TWEET HISTORY

The Tweet itself had been conceived a decade earlier. First proposed by Cessna during the Korean War, it was intended to be the US Air Force’s next primary jet trainer. Having secured the TX (Trainer Experimental) contract in 1954, the Cessna design was finalised as a working prototype.

The resulting product was surprisingly impressive for a trainer—especially considering Cessna’s lack of experience in jet aviation at that point. Powered by two Continental J69 engines and weighing just 5000 pounds empty, the aircraft was both small and relatively fast. The instructor and student would sit side by side—something that was becoming less common in newer jet designs, but was nonetheless extremely helpful.

As outlined in the TX request, the jet met a very dynamic, ambitious set of parameters; to give the student as much latitude as possible, the aircraft could be flown at altitudes exceeding 30,000 feet while retaining safe handling for an amateur. These same predictable flight characteristics translated to good handling at low altitudes, with great handling in dense air near sea level and at low or near-stalling speeds.

A slow approach speed, plus engine attenuators, made it both easy and safe to land on shorter fields; the students would have more reaction time, and the instructor could keep the engines spooled up in case of a go-around.

Inside the cockpit, a dense instrument panel offered a look similar to what would be found in a frontline fighter, while the core controls and functionality were simple enough for a student to quickly get the hang of.

Finally, the aircraft itself was robust, reliable, and easy to maintain on the ground. Thanks to dozens of simple access panels, component replacement was particularly easy; for example, it was claimed that, in ideal conditions, a crew could swap out an engine in half an hour.

As a whole, the Cessna design not only made for a great trainer but also had all the characteristics the military believed would make a counterinsurgency platform.

DEVELOPMENT

Building on the base design and integrating the requested changes, the first working prototype emerged in October 1964. Designated the YATD-37D, it was close to what the Air Force envisioned. Cessna had stripped the old J69s, replacing them with the new General ElectricGeneral Electric (GE) Aerospace: A foundational American industrial corporation that pioneered the development of jet propulsion in the United States.... More J85-J2, which produced double the power per engine.

For stores, the wings were reinforced with new wingtip fuel tanks, complemented by three hardpoints per wing, and a GAU-2 minigun in the nose with 1500 rounds of 7.62.

The pylons, from inboard to outboard, were generally rated to carry 860 pounds on the inner four, 600 pounds on the middle two, and 500 pounds on the outer two. If needed, the aircraft could also carry up to four sidewinders on these outer pylons.

With new engines, it could operate up to 41,000 feet, with a top speed of 440 knots and a stall speed of 98 knots. With max payload, the aircraft could travel a decent distance, with a combat radius of 400 nautical miles and a max range of over 800 nautical miles with four drop tanks onboard. With its final engine – the J85-17A – it could produce over 5700 pounds of total thrust.

Thanks to this, take-offs were relatively short, and the climb rate was decent. As would later be noted by pilots operating out of Bien Hoa in Vietnam, Dragonfly crews could already be at 1000 feet by the end of the airstrip, while armed-up Huns would only just be climbing out of ground effect. If deployed on smaller, less-developed strips, this would be a huge advantage.

Internally, a new gunsight, gun camera, and avionics were added, and the cockpit itself would be unpressurised. Given that it would hug the ground most of the time, this wasn’t much of an issue, but it did save weight. Armed up, it was compatible with a wide variety of common ordnance, from napalm to cluster weapons, iron bombs, and rockets. In fact, almost 3,000 pounds of weaponry could be carried at once —yet how this would fare in combat was yet to be tested.

After a lull in interest, the program was reawakened in 1966. Since the idea was first conceived, the need for a dedicated COIN platform had only increased. In theatre, the A-1 had taken up most COIN sorties. Although such missions were considered lower priority, they were nonetheless costly. A-1s were now showing their age and increasingly difficult to maintain. What’s more, the dangerous COIN missions could indeed knock these Skyraiders out of action at a time when they were still needed to complement the Hun in far more important CAS and search-and-rescue missions.

In response, the decision was made to order 39 A-37As, now designated the Dragonfly.

VIETNAM SERVICE ‘COMBAT DRAGON’

In August 1967, the 604th Air Combat Squadron set off for Bien Hoa Air Base in South Vietnam, accompanied by the first 25 A-37As.

Commencing on the 15th, an evaluation program – designated Combat Dragon – would push the aircraft to its limits. Organised by World War 2 veteran Lieutenant Colonel Lou Weber, the plan was to prove the aircraft in combat, despite having undergone essentially no testing at home. The 30 assigned pilots were to come from a variety of aircraft types, to validate that anyone could learn it quickly. In World War 2 style, there would be no multi-month conversion course or training program. Instead, pilots would be taught the basics, strapped in, and sent out, usually one per plane, with the other seat empty.

If it worked, it would not only validate the aircraft but also give pilots and ground crews real-world experience.

As recalled by former pilot Lon Holtz, who had also flown the Phantom, their arrival at Bien Hoa was rough. The aircraft had arrived on Starlifters as kits, set up by Cessna technicians in front of onlooking Super Sabre pilots. In an interview with Smithsonian, he remembers his crew constantly getting flak at the officers’ club, earning the nickname “Mattel Marauders”, and their planes earning the moniker “Super Tweet”.

Despite their rather comical arrival, the jets soon proved themselves a deadly asset when they started operations.

Troop support, dynamic interdiction, and other air-to-ground missions in counter-insurgency operations were flown, averaging 12 sorties per day. Sorties expanded to encompass Tiger Hound, the codename for an interdiction operation in south-eastern Laos, an area used by the North to ferry weapons, and a joint task force assigned to destroy them. Combat Dragon, in its first three months, saw over 4000 sorties flown without losing an aircraft to enemy fire.

The squadron was reassigned to the 14th Air Command Wing in Nha Trang, and evaluation reports were prepared. Pilots noted that, regardless of tasking, the aircraft remained dynamic; even when loaded, it remained relatively agile, with good acceleration and robust armour plating. Pilots noted that, to their surprise, their scarily slow run-in speeds were actually saving them. Gunners regularly over-led them, with rounds and tracers well ahead.

On ingress routes, pilots could fly on one engine, drastically improving performance, and on station, could fly slowly enough to strafe or strike targets with great accuracy. In fact, the average accuracy reported was a circular error probable of 45 feet, less than half that of the latest F-4D using computer bombing.

On one sortie, Holtz recalls taking over from an F-4, when a forward air controller radioed in, blurting out, “Thank God, now I have somebody who can actually hit the damn target”.

This good reputation was also evident among ground crews; maintenance requirements were about two hours per flight hour – among the lowest for any combat jet in theatre.

Despite all the flak it received, the Super Tweet was shaping up to be a winning design.

A-37B ARRIVES

In September, a refined prototype emerged; the A-37B. Noting the few drawbacks highlighted by pilots, including fuel capacity and power, the new design had been overhauled. Larger fuel stores had been added, alongside new avionics, and more powerful J85 GE-17A engines had replaced the older GE-5 engines.

The 37B would increase the external stores capacity from around 2700 pounds to an impressive 5800 pounds.

Other modifications – some implemented slightly later – included the adoption of a further-strengthened undercarriage and wings, an improved six G airframe rating, self-sealing fuel tanks, and armour curtains around the lower half of the cockpit to shield against small-arms fire.

Lastly, it would receive aerial refuelling in the form of a probe protruding from the nose of the airframe.

It was claimed that some loadouts on the 37B could exceed 6000 pounds. If true, this meant the aircraft – which was around 6200 pounds dry – could hypothetically carry close to its own weight in weaponry. Regardless, with a gross take-off weight of 14,000 pounds, the 37B had doubled the capacity of the old T-37 —an impressive feat given that it was still a very similar airframe.

Deliveries began shortly after, in early 1968, and were sent to the South Vietnamese Air Force to supplement the ageing Skyraiders.

In the years that followed, both models would see extensive use by the South and the US Air Force. As recalled by former Tweet pilot Robert Macaluso, the airframe never received much recognition, either from the public or within the air force. Despite all this, crews flew some of the war’s craziest interdiction and troop-support missions.

Often hugging the ground during ingress, ground crews began finding twigs and leaves caught in the undercarriage. Captain Bob Chappelear recalls one instance during an egress when he accidentally hit a tree, slicing the top off and completely crushing the leading edge of his aircraft. A ruptured napalm canister sprayed jelly all over the frame, and the aircraft began yawing. Amazingly, the aircraft made it back, albeit with a 25-degree bend in the wing. Maintenance officer Charlie Kraesig recalls that unknowingly grazing treetops had become surprisingly common, but luckily not fatal.

As time went on, night missions also increased. Major Richard Martel – who had been on Combat Dragon – noted being called upon for late-night troop support flights. During one instance, Martel and a wingman had been orbiting over a flight of Huns, strafing the borders of a special forces outpost. Once Winchester, the Huns had left, leaving hundreds of Viet Cong closing in on the base. A Forward Air Controller urgently requested that the two Tweets roll in. They did. Diving from 6000 feet to the deck, the pair released weapons, pulled off, and made a second pass with iron bombs to knock out gun emplacements. Upon returning, Martel – who had wanted to fly support roles to avoid killing – was notified that the two of them had inflicted a terrifying amount of damage, wiping out an estimated 200 enemies during their passes and saving the base.

By April/May 1968, the original Combat Dragon crews had flown around 10,000 sorties, thanks mainly to quick turnaround times. John Bradley – who would go on to become a general and chief of the Air Force Reserve – recalls his squadron looking over a 1971 edition of Stars and Stripes, which noted an ‘incredible’ 680-sortie month for an F-4 unit. As Bradley put it, “man, we’d just flown 1200”.

Throughout its tenure, the Dragonfly didn’t operate in the north but continued to see extensive action by Southern forces, all the way up until the eventual fall of Saigon. In fact, in one well-known incident on April 28th 1975, the North captured 95 Super Tweets and began flying them on attack runs against Tan Son Nhut Air Base.

END OF PROGRAM

By 1974, an Air Force report stated that the Super Tweet had flown 68,471 sorties and undoubtedly saved many friendly forces that were pinned down. Yet despite all this, it never received the recognition it deserved. Bob Chappelear, in describing his last full day in Vietnam, noted that he’d expected something special, like what was pictured in fighter magazines, having just flown his 475th mission and preparing to leave. Instead, he was called up at midnight to fly another sortie, then a napalm run at daybreak. Upon landing, he remembers simply parking and walking away for a shower before catching his flight home—an experience likely shared by other Super Tweet crews despite the effort they put in.

The A-37 would live on. After the war, the 95 captured airframes continued to be operated by the VPAF and were then phased out and sold off once parts expired.

Back home in the States, the aircraft faced a similar fate. Despite the strong track record, its niche role was deemed unnecessary, and Tactical Air Command transferred the aircraft to the Air National Guard and Reserve. Newer fourth-gen designs, such as the Warthog, could fill a similar COIN role if needed, albeit with greater endurance and more modern systems.

The platform’s final American use would be in forward air control. While details are scarce, it had already filled a FAC role in Vietnam, but an official overhaul wasn’t completed until at least the late 70s. By this point, many were officially redesignated as the OA-37, stripped of their guns, and rewired with newer avionics and radio controls. Pilot testimony recalls the aircraft usually carrying four underwing tanks during these flights, alongside the wingtip tanks, which limited visibility. The spare pylons would carry phosphorus rockets or flare dispensers on night sorties.

In this role, the aircraft would see its final action in Panama during Operation Just Cause. 24 aircraft from the 24th Tactical Air Support Squadron would see action. Notably, these were the only remaining Dragonflies that retained their weapon capabilities, and the Squadron itself – under Lieutenant Colonel Bill Wilson – was well familiar with Panama’s layout. These pilots had spent the 1980s conducting operations out of Panama into neighbouring countries such as Peru and Ecuador to support allied governments.

Upon the commencement of Just Cause, the squadron would play a crucial role both in the air and with some crewmen serving as Enlisted Terminal Attack Controllers on the ground.

Wilson recalled that during the operation, pairs of Dragonflys were on overflight for troops around the clock for three days, during which crews engaged targets with high-explosive rockets.

Working closely with National Guard A-7Ds, this operation marked the send-off of both airframes. The Dragonfly – now well past its prime – was finally phased out. On 1 March 1991, the 24th Tactical Air Support Squadron was inactivated, bringing regular USAF OA-37 operations to an end.

The aircraft would live on with several other air forces, most of which were in Latin America, and almost all of which actually used it in live combat.

Despite being largely overlooked, it was one of several designs that validated the idea of using trainers as combat aircraft. In June 1967, just before Combat Dragon, the Israelis had used modified French Magisters in the Six-Day War. In October, the British had begun testing the visually similar BACBritish Aircraft Corporation (BAC): A major British aerospace manufacturer formed in 1960 through the government-mandated merger of English Electric A... More Strikemaster, and throughout this period, Macchi 326s were being prepared for light attack.

In total, 577 Dragonflies would be built. Small, strong, and armed to the teeth, the Dragonfly was an impressive achievement for Cessna, albeit one that never received the praise it deserved.