Boeing Y1B-9

Infobox Aircraft
name=Boeing YB-9/Y1B-9


caption=Y1B-9 test flight, 1932.
type=Bomber aircraft
manufacturer=Boeing
designer=
first flight=1931-04-29
introduced=
retired=1934
status=No surviving examples
primary user=United States Army Air Corps
more users=
produced=1930-1933
number built=7
unit cost=
variants with their own articles=The Boeing B-9 was the first all-metal monoplane bomber aircraft designed for the United States Army Air Corps. The first service model, dubbed the YB-9, was originally tested and developed by the United States aircraft manufacturing company Boeing as XB-901 and first flew on April 29, 1931. The YB-9 was an enlarged alteration of Boeing's Model 200 Commercial Transport. The Pratt & Whitney R-1830-13 radial engines used on the YB-9 gave it a top speed of 163 mph (262 km/h).

The second test model, named the Y1B-9 ("Y1B-" indicating funding outside normal fiscal year procurement), used liquid-cooled Curtiss V-1570-29 'Conqueror' engines. The increased power from these engines, combined with increased streamlining of the engine nacelles, increased its top speed to 173 mph (278 km/h). With the exception of the B-2 Condor, liquid-cooled engines were never used on production bombers for the United States military. The air-cooled radial engine was lighter and more reliable than the liquid-cooled engine, and less vulnerable to enemy damage.

The Y1B-9A was an improved version of the YB-9, featuring more powerful engines and a redesigned vertical stabilizer. Utilising two Pratt & Whitney R-1860-11 Hornet engines, the plane was faster than any contemporary fighter aircraft.Fact|date=September 2008 The Y1B-9 was the first enclosed-cockpit plane flown by the Army. Its high speeds made open cockpits extremely impractical. Five were ordered by the Army in September 1931.

pecifications (Y1B-9A)

aircraft specifications
plane or copter?=plane
jet or prop?=prop
crew=4
length main=51 ft 6 in
length alt=15.7 m
span main=76 ft 10 in
span alt=23.4 m
height main=12 ft 8 in
height alt=3.86 m
area main=954 ft²
area alt=88.6 m²
empty weight main=8,941 lb
empty weight alt=4,056 kg
loaded weight main=13,932 lb
loaded weight alt=6,320 kg
max takeoff weight main=14,320 lb
max takeoff weight alt=6,500 kg
number of props=2
type of prop=radial engine
engine (prop)=Pratt & Whitney R-1860-11 "Hornet"
power main=600 hp
power alt=450 kW
max speed main=188 mph
max speed alt=163 knots, 302 km/h
cruise speed main=165 mph
cruise speed alt=143 knots, 265 km/h
range main=540 mi
range alt=470 nm, 870 km
ceiling main=20,750 ft
ceiling alt=6,325 m
loading main=14.6 lb/ft²
loading alt=71.3 kg/m²
power/mass main=0.0861 hp/lb
power/mass alt=142 W/kg
guns=2× .30 in (7.26 mm) machine guns
bombs=2,200 lb (1,000 kg) bombs

References

*cite journal|author=Alain Pelletier|title=End of the Dinosaurs: Boeing's B-9, Breaking the Bomber Mold|journal=Air Enthusiast|year=2002|volume=101
*cite book|author=Wagner, Ray|year=1982|title=American Combat Planes| location=New York | publisher=Doubleday|id=ISBN 0-930083-17-2
*cite book|author=Jones, Lloyd|year=1974|title=U. S. Bombers| location=Fallbrook | publisher=Aero|id=ISBN 0-8168-9126-5
*cite web|title=Boeing B-9|work=Encyclopedia of American Aircraft|accessyear=2005|accessdate=April 10|url=http://home.att.net/~jbaugher2/b9.html
*cite web|title=Boeing Y1B-9|work=USAF Museum|accessyear=2004|accessdate=August 1|url=http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2443

ee also

aircontent
related=
* Boeing Monomail
similar aircraft=
* Martin B-10
lists=
* List of bomber aircraft
* List of military aircraft of the United States