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Boeing 214 Y1B-9

Boeing 215 XB-901 YB-9

Boeing 246 Y1B-9A

 

Boeing-YB9


In 1930 Boeing began the private-venture development of a bomber aircraft based on the Model 200 Monomail. The resulting prototypes and service evaluation bombers were scaled-up versions of this aircraft. They differed by having twin-engines, installed in nacelles at the wing leading edge, and by adaptation of the fuselage to cater for the crew and weapons.

 

Boeing-Y1B-9A
Y1B-9A

 

To provide the crew accommodation, the fuselage was extended forward of the wing. A bomb-aimer/gunner was accommodated in the nose and immediately behind him, within the fuselage, was a radio operator's position. Aft of the radio operator were two cockpits in tandem, for pilot and co-pilot, with a fourth open cockpit, just aft of the wing trailing edge, for the rear gunner. A bombload totalling 1025kg could be divided between an internal bomb bay and underwing racks.

boeingy1b9
Y1B-9


First flying, on 13 April 1931, was the Boeing Model 215, powered by two 429kW Pratt & Whitney R-1860-13 Hornet radials. This was tested by the USAAC under the initial designation XB-901 (Experimental Bomber), and satisfactory conclusion of testing resulted in the procurement of this aircraft under the designation YB-9. At the same time the then incomplete Boeing Model 214 was contracted under the designation Y1B-9, plus five additional service test aircraft with the designation Y1B-9A (Model 246).


The Model 214, powered by 447kW Curtiss V-1570-29 Conqueror inline engines, was flown for the first time on 5 November 1931, and following further tests, the Model 214 was re-engined with a supercharged version of the Pratt & Whitney Hornet. This power-plant was chosen also for the Y1B-9As, the first of which was flown on 14 July 1932. The Y1B-9A differed externally from the earlier prototypes in having modified vertical tail surfaces, and had internally a number of equipment and structural changes to meet service requirements.


Subsequent testing, and evaluation against the Martin Model 123, resulted in the Martin aircraft entering service as the B-10. This came as a great disappointment to the Boeing company, which had produced this bomber with performance superior to most contemporary fighter aircraft.

 

boeingb9
 

Boeing 215 / XB-901 / YB-9
Engines: 2 x Pratt & Whitney R-1860-13 Hornet radials, 429kW

Boeing 214 / Y1B-9
Engines: 2 x Curtiss V-1570-29 Conqueror inline, 447kW
re-engined with 2 x 447kW Pratt & Whitney SR-1860-11 Hornetsupercharged radial piston

Boeing 246 / Y1B-9A
Engine: 2 x Pratt & Whitney SR-1860-11 Hornet, 447kW / 600 hp
Take-off weight: 6495 kg / 14319 lb
Empty weight: 4056 kg / 8942 lb
Wingspan: 23.42 m / 76 ft 10 in
Length: 15.77 m / 51 ft 9 in
Height: 3.66 m / 12 ft 0 in
Wing area: 88.63 sq.m / 954.00 sq ft
Max. speed: 299 km/h / 186 mph / 163kt
Cruise speed: 266 km/h / 165 mph
Ceiling: 6325 m / 20750 ft
Rate-of-Climb: 900ft/min (274m/min)
Range: 869 km / 540 miles
Armament: 2-4 x 0.30 caliber machine guns
Bombload: 2,260lbs
Accommodation: 4 or 5

 

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