The Boeing XF6B-1 (later redesignated XBFB-1) was an experimental biplane developed by Boeing for the United States Navy in the early 1930s. It was Boeing’s final biplane design for the U.S. Navy, marking the end of an era as military aviation transitioned to more advanced monoplane configurations. Only one prototype, designated Model 236, was built. Although the XF6B-1 showed promise in certain areas, it ultimately did not meet the Navy’s requirements and never entered production.
Design and Development
The XF6B-1 was ordered by the U.S. Navy on June 30, 1931, as part of an effort to develop a versatile aircraft capable of fulfilling multiple roles, including fighter and bomber duties. The design was a derivative of the earlier Boeing F4B, a highly successful naval fighter of the late 1920s. However, the XF6B-1 featured significant changes, including nearly all-metal construction. Only the wings retained the fabric covering common in biplane designs of the era.
The aircraft was powered by a 625-horsepower Pratt & Whitney R-1535-44 Twin Wasp radial engine, which provided considerable power for the time. The XF6B-1 had a gross weight of 3,704 pounds, which was approximately 700 pounds heavier than the F4B. This additional weight, combined with its rugged construction, made the aircraft durable and able to withstand the high stresses of dive-bombing, but it compromised the plane’s maneuverability, which was essential for a fighter.
Unclear Role
Initially conceived as a fighter, the XF6B-1 faced challenges in fulfilling that role due to its heavy weight and reduced agility compared to other naval fighters of the time. Although the aircraft could handle high g-forces, its weight and bulk reduced its performance in dogfighting scenarios, where maneuverability and speed were critical.
In recognition of its capabilities as a fighter-bomber, the Navy re-designated the aircraft as XBFB-1 in March 1934, with “BFB” standing for Bomber-Fighter. This shift reflected the growing realization that while the XF6B-1 was not an ideal fighter, it might still be useful in a bombing role. Modifications were made to improve its performance, including changes to the engine cowling and streamlining of the landing gear, as well as the installation of a three-bladed propeller to replace the standard two-bladed prop, though these efforts failed to produce the desired results.
Operational History
Despite attempts to enhance its performance, the Boeing XF6B-1/XBFB-1 did not meet the Navy’s expectations. It remained inferior to competing designs, particularly the Curtiss F11C Goshawk, which outperformed the XF6B in terms of speed, maneuverability, and overall effectiveness in the fighter role.
The prototype first flew in early 1933, but after several years of testing, its operational future became uncertain. The aircraft met an unfortunate end in 1936 when it rammed into a crash barrier during testing. Following this incident, the Navy decided not to pursue the design further, marking the end of Boeing’s involvement in biplane fighter development.
Performance Limitations
The XF6B-1’s failure to meet operational standards reflected the broader shift occurring in military aviation during the 1930s. As aircraft designs evolved, the limitations of biplanes became increasingly apparent. Monoplanes, with their superior speed, range, and aerodynamics, were beginning to dominate military aviation. The XF6B-1, despite its advanced features for a biplane, was unable to compete with newer designs that emphasized these characteristics.
Specifications
- Crew: 1
- Length: 22 ft 1.5 in (6.73 m)
- Wingspan: 28 ft 6 in (8.68 m)
- Height: 10 ft 7 in (3.22 m)
- Wing Area: 252 sq ft (23.41 m²)
- Empty Weight: 2,823 lb (1,281 kg)
- Gross Weight: 3,704 lb (1,680 kg)
- Powerplant: 1 × Pratt & Whitney R-1535-44 radial engine, 625 hp (466 kW)
Performance
- Maximum Speed: 200 mph (322 km/h, 170 kn)
- Cruise Speed: 170 mph (274 km/h, 150 kn)
- Range: 525 mi (845 km, 456 nmi)
- Rate of Climb: 1,190 ft/min (6.04 m/s)
Armament
- 2 × .30-inch machine guns
- 1 × 500 lb (227 kg) bomb
Legacy
Although the Boeing XF6B-1/XBFB-1 did not achieve operational success, it serves as a historical example of the transitional phase in naval aviation during the 1930s. The design represents the culmination of Boeing’s biplane efforts and underscores the challenges that aircraft manufacturers faced as military aviation evolved towards faster, more capable monoplane fighters.
Operators
- United States Navy
| XF6B | |
|---|---|
| General information | |
| Type | Carrier-based fighter-bomber |
| National origin | United States |
| Manufacturer | Boeing |
| Status | Cancelled |
| Number built | 1 |
| History | |
| First flight | 1 February 1933 |
| Developed from | Boeing F4B |
References
- Angelucci, Enzo. The American Fighter. Sparkford: Haynes Publishing Group, 1987, pp. 85–86.
- Jones, Lloyd S. U.S. Naval Fighters. Fallbrook, California: Aero Publishers, 1977, pp. 115–117. ISBN 0-8168-9254-7.
- Taylor, Michael J. H. Jane’s Encyclopedia of Aviation. London: Studio Editions, 1989. ISBN 0-517-69186-8.
- World Aircraft Information Files. London: Bright Star Publishing, 1985.
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