AIR FORCE/MILITARY HISTORY
A-37 Dragonfly AKA "Tweety Bird"
The Cessna A-37 Dragonfly, or Super Tweet, is an American light attack aircraft developed from the T-37 Tweet basic trainer in the 1960s and 1970s by Cessna of Wichita, Kansas.
The A-37 was introduced during the Vietnam War and remained in peacetime service afterward.
The growing American military involvement in Vietnam in the early 1960s led to strong interest in counter-insurgency (COIN) aircraft. In late 1962, the U.S. Air Force's Special Air Warfare Center at Eglin Air Force Base's Hurlburt Field in Florida evaluated two T-37Cs for the role.
The Air Force found the T-37 promising, but wanted an improved version of the aircraft that could carry a much larger payload, and had much greater endurance and better short-field performance. This meant a heavier aircraft with more powerful engines. In 1963, the Air Force awarded a contract to Cessna for two prototype YAT-37D aircraft: T-37s with modifications that included:
- Stronger wings.
- Three stores pylons on each wing.
- Larger wingtip fuel tanks of 360 litre (95 US gallons) capacity.
- A General Electric GAU-2B/A 7.62 mm "Minigun" Gatling-style machine gun, with a rate of fire of 3,000 rounds/minute and 1,500 rounds of ammunition. The weapon was fitted in the right side of the aircraft's nose behind a large, convenient access panel. A gunsight and gun camera were also fitted.
- Better avionics for battlefield communications, navigation, and targeting.
- Tougher landing gear for rough-field operation.
These changes meant a drastic increase in aircraft weight and the aircraft now had to carry a significant payload as well. Cessna, therefore, doubled the engine power by replacing the two Continental J-69 engines with General Electric J85-J2/5 turbojet engines with 2,400 lbf (10.7 kN) thrust each.
The first YAT-37D flew in October 1964, followed a year later by the second prototype. The second prototype had four stores pylons under each wing, rather than three, and the first prototype was upgraded to this configuration as well.
In August 1967, 25 A-37As were sent to Vietnam under the "Combat Dragon" evaluation program, and flew from Bien Hoa Air Base on USAF "air commando" missions, including close air support, helicopter escort, FAC, and night interdiction. Combat loads 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 fuel tanks on the inner stores pylons.
During this period, the A-37As flew thousands of sorties. None were lost to enemy fire, although 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 Republic of Vietnam Air Force (VNAF)s, providing 2,850 lbf (12.7 kN) 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-37 excelled at close air support. It could engage targets 100 miles per hour slower than swept-wing fighters. The slower speed improved bombing accuracy, enabling pilots to achieve an average accuracy of 45 feet (13.7 m).
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.
T-37 Trainer Varient
- Maximum speed: 507 mph (440 kn, 816 km/h) at 16,000 ft
- Cruise speed: 489 mph (425 kn, 787 km/h) at 25,000 ft
- Stall speed: 113 mph (98 kn, 182 km/h)
- Range: 920 mi (800 nmi, 1,480 km)
- Combat radius: 460 mi (400 nmi, 740 km) with 4,100 lb warload
- Service ceiling: 41,765 ft (12,730 m)
- Rate of climb: 6,990 ft/min (35.5 m/s)
- Wing loading: 65 lb/ft² (318 kg/m²)
- Thrust/weight: 0.47