Fairchild AT-21 Gunner

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Fairchild AT-21 Gunner: An Overview

The Fairchild AT-21 Gunner was a specialized bomber crew trainer developed by the Fairchild Aircraft Company during World War II. Designed to train aircrews on the use of power gun turrets and flexible-mounted guns, the AT-21 aimed to replicate the various roles within a bomber crew, including piloting, navigation, bomb aiming, and aerial gunnery. Despite its innovative design and intentions, the aircraft had a brief operational history and was eventually replaced by modified bombers that were better suited for training purposes.

Design and Development

The genesis of the AT-21 Gunner can be traced back to a specification issued by the United States Army Air Corps (USAAC) for a specialized bomber trainer. In response to this request, Fairchild Aircraft was tasked to design two prototypes. The first prototype, designated XAT-13, was powered by dual Pratt & Whitney R-1340-AN-1 radial engines, each generating 450 horsepower. This prototype showcased a compact bomber design equipped with a single machine gun in the nose and a dorsal turret housing twin machine guns. It also featured tricycle landing gear, an innovative design choice intended to enhance ground handling capabilities.

The second prototype, known as XAT-14, was similar in layout but incorporated enhancements such as two 520 horsepower Ranger V-770 inline inverted 12-cylinder engines. This prototype took to the skies for its first flight in late 1942. In an effort to refine the aircraft for bombardier training purposes, modifications were made that included the removal of both the nose gun and turret; it was subsequently re-designated as XAT-14A. Notably, both prototypes utilized “Duramold,” a type of plastic-bonded plywood that contributed to their unique construction.

After testing concluded, the USAAC opted for the XAT-14A as the basis for its production version, which became known as the AT-21 Gunner. Designed specifically for gunnery training, this version could accommodate a crew of five: a pilot, co-pilot or gunnery instructor, and three students. Production began in 1943 at Fairchild’s Hagerstown facility and later expanded to their Burlington plant in North Carolina. Additionally, Bellanca Aircraft and McDonnell Aircraft were enlisted to help meet production demands.

Operational History

Despite its promising design, the AT-21 encountered several significant issues during its operational tenure. Pilots reported difficulties related to vibration and oscillation tendencies inherent in the aircraft’s structure. Furthermore, an aerodynamic instability stemmed from the short distance between the rudders and gull wings, leading to unacceptable yaw during rudder inputs—even slight ones.

Due to these challenges, the AT-21 was deemed unsuitable for its original training purpose. The USAAC then explored its potential as an advanced pilot trainer; however, this initiative also faced hurdles due to poor performance when flown on a single engine along with persistent landing gear malfunctions. Consequently, by 1944, the aircraft was withdrawn from service as a trainer.

In light of its shortcomings as a crew trainer, many AT-21s were repurposed for target-towing duties—an alternative use that allowed them to remain relevant within military operations. A few examples of this aircraft managed to survive in civilian hands post-war; one notable instance is serial number 42-48053, currently owned by Craig Cantwell and located in North Texas while awaiting restoration.

BQ-3 Assault Drone

In addition to its role as a training aircraft, designs based on the AT-21 led to further innovations within military aviation. In October 1942, the U.S. Army Air Forces commissioned two XBQ-3 “aerial torpedoes,” which were conceptualized from the AT-21’s framework. Intended primarily for flight testing while being optionally piloted, these drones were designed to carry substantial explosive payloads—specifically 4,000 pounds (approximately 1,800 kilograms). The XBQ-3 took its maiden flight in July 1944; however, similar to its predecessor’s fate as a trainer aircraft, this project was ultimately canceled later that same year.

Variants of Fairchild AT-21

The development process of the AT-21 yielded several variants tailored for specific roles:

  • XAT-13: The initial twin-engine prototype powered by two Pratt & Whitney R-1340-AN-1 engines; only one unit was built (serial number 41-19500).
  • XAT-14: An upgraded model of XAT-13 featuring two Ranger V-770 engines; one was constructed before being converted into XAT-14A (serial number 41-19503).
  • XAT-14A: A modification of XAT-14 designed for bombardier training with key armaments removed.
  • AT-21: The production version based on XAT-14A featuring two Ranger V-770 engines; a total of 164 units were manufactured.
  • XBQ-3: A guided bomb variant derived from AT-21 designed to carry an explosive charge.

Specifications of AT-21

The specifications of the AT-21 provide insight into its design and capabilities:

  • Crew: Five personnel
  • Length: 38 feet (12 meters)
  • Wingspan: 52 feet 8 inches (16.05 meters)
  • Height: 13 feet 1.25 inches (3.9942 meters)
  • Wing Area: 378 square feet (35.1 m²)
  • Empty Weight: 8,654 pounds (3,925 kg)
  • Gross Weight: 11,288 pounds (5,120 kg)
  • Max Takeoff Weight: 12,500 pounds (5,670 kg)
  • Powerplant: Two Ranger V-770 engines generating 520 hp (390 kW) each
  • Maximum Speed: 196 knots (225 mph or 362 km/h)
  • Cruise Speed: 170 knots (196 mph or 315 km/h)
  • Range: 790 nautical miles (910 miles or 1,460 km)
  • Service Ceiling: 22,150 feet (6,750 m)
  • Rate of Climb: 930 feet per minute (4.7 m/s)
  • Armament:
    • One .30 inch Browning trainable machine gun in the nose
    • Two .30 inch Browning machine guns in a power-operated dorsal turret

Conclusion

The Fairchild AT-21 Gunner represents an intriguing chapter in

Artykuł sporządzony na podstawie: Wikipedia (EN).