Boeing YB-9
YB-9 | |
---|---|
Role | Bomber aircraft
|
Manufacturer | Boeing |
First flight | 13 April 1931 |
Introduction | 5 November 1931 |
Retired | 1935 |
Status | No surviving examples |
Primary user | United States Army Air Corps |
Produced | 1930–1933 |
Number built | 7 |
The Boeing YB-9 was the first all-metal monoplane bomber aircraft designed for the United States Army Air Corps. The YB-9 was a much enlarged twin-engine development of Boeing's single-engine Model 200 Monomail commercial transport.
Design and development
In May 1930,
Boeing built two prototypes of a new bomber as a private venture, which differed in the engines used, with the Model 214 powered by two liquid-cooled
The first of the two prototypes to fly was the radial powered Model 215 which, carrying civil markings and the aircraft registration X-10633, made its first flight on 13 April 1931.[6][7] It was leased to the Air Corps for testing under the designation XB-901, demonstrating a speed of 163 mph (262 km/h). Testing was successful, and both the XB-901 and the as-yet incomplete Model 214 were purchased as the YB-9 and Y1B-9 respectively on 13 August 1931, with an order for a further five for service testing following.[2][8]
The Y1B-9 (Y1 indicating funding outside normal fiscal year procurement), powered by two liquid-cooled Curtiss V-1570-29 'Conqueror' engines, first flew on 5 November 1931. The increased power from these engines, combined with improved streamlining of the engine nacelles, increased its top speed to 173 mph (278 km/h). The YB-9, meanwhile, had been re-engined with more powerful Hornet Bs, demonstrating slightly better performance than the Y1B-9, which was therefore also re-engined with Hornet Bs.[2][8]
The five Y1B-9A service test aircraft (Boeing Model 246) had the Pratt & Whitney R-1860-11 Hornet B engines which powered the re-engined YB-9 and Y1B-9 and a redesigned vertical stabilizer modeled on the 247D transport. While enclosed canopies were considered and designed, the B-9 was never fitted with them.[8] Although it equaled the speed of existing American fighter aircraft,[9] no further aircraft were built, as the Glenn L. Martin Company had flown a prototype of a more advanced bomber, the XB-907, which was ordered into production as the Martin B-10.[6]
Operational history
The first of the five Y1B-9As entered service with the
Variants
- YB-9 (one produced). Pratt & Whitney R-1860-13 Hornet B (575 hp or 429 kW). Reengined with supercharged Pratt & Whitney R-1860-11 Hornet B (600 hp or 450 kW) and was fitted with three-bladed propellers. Trim tab ran the full height of the rudder
- Boeing model B-215
- contract number: XB-901
- Y1B-9 (one produced). Curtis V-1570-29 Conqueror) (600 hp). Reengined with supercharged Pratt & Whitney R-1860-11 Hornet B(600 hp) and was fitted with three-bladed propellers. Short trim tab on rudder.
- Boeing model B-214
- Y1B-9A (five produced). Pratt & Whitney R-1860-11 Hornet B (Y1G1SR-1860B) (600 hp). Metal instead of fabric covering on the control surfaces. There were also many internal structural and equipment changes
- Boeing model B-246
Operators
Specifications (Y1B-9A)
Data from United States Military Aircraft since 1909[11]
General characteristics
- Crew: four
- Length: 52 ft 0 in (15.85 m)
- Wingspan: 76 ft 10 in (23.42 m)
- Height: 12 ft 0 in (3.66 m)
- Wing area: 954 sq ft (88.6 m2)
- Empty weight: 8,941 lb (4,056 kg)
- Max takeoff weight: 14,320 lb (6,495 kg)
- Powerplant: 2 × Pratt & Whitney R-1860-11 Hornet B radial engine, 600 hp (450 kW) each
Performance
- Maximum speed: 188 mph (303 km/h, 163 kn) at 6,000 ft (1,800 m)
- Cruise speed: 165 mph (266 km/h, 143 kn)
- Range: 540 mi (870 km, 470 nmi)
- Service ceiling: 20,750 ft (6,320 m)
- Rate of climb: 900 ft/min (4.6 m/s)
Armament
- Guns: 2 × .30 in (7.62 mm) machine guns
- Bombs: 2,260 lb (1,030 kg) bombs
See also
Related development
Aircraft of comparable role, configuration, and era
Related lists
- List of bomber aircraft
- List of military aircraft of the United States
References
Citations
- ^ Pelletier 2002, p. 44.
- ^ a b c Swanborough and Bowers 1963, p. 72.
- ^ Bowers 1989, p. 200.
- ^ Pelletier 2002, pp. 44–45.
- ^ Bowers 1989, pp. 200–201.
- ^ a b Bowers 1989, pp. 202–203.
- ^ Pelletier 2002, p. 47.
- ^ a b c Pelletier 2002, pp. 46–47.
- ^ "YB-9 factsheet." Archived August 29, 2007, at the Wayback Machine National Museum of the United States Air Force. Retrieved 7 July 2010.
- ^ Pelletier 2002, pp. 48–49.
- ^ Swanborough and Bowers 1963, p. 73.
Bibliography
- Baugher, Joe (10 September 2002). "Boeing B-9". Encyclopedia of American Aircraft. Retrieved 7 July 2010.
- Bowers, Peter M. (1989). Boeing Aircraft since 1916. London: Putnam. ISBN 0851778046.
- Jones, Lloyd (1974). U. S. Bombers. Fallbrook, CA: Aero Publishers. ISBN 0816891265.
- Pelletier, Alain (September–October 2002). "End of the Dinosaurs: Boeing's B-9, Breaking the Bomber Mold". Air Enthusiast. Vol. 101. pp. 44–49.
- Swanborough, F. G.; Bowers, Peter M. (1963). United States Military Aircraft since 1909. London: Putnam.
- Wagner, Ray (1982). American Combat Planes. New York: Doubleday. ISBN 0930083172.