Boeing 221

infobox Aircraft
name = Model 200 and 221 Monomail
type = Airliner
manufacturer = Boeing

---

caption =
designer =
first flight = 6 May 1930
introduced =
retired =
status =
primary user =
more users =
produced =
number built =
unit cost =
variants with their own articles = The Boeing Model 200 Monomail was an American mail plane of the early 1930s.

Design and development

The aircraft marked a departure from the traditional biplane configuration for a transport aircraft, instead featuring a single, low set, all metal cantilever wing. Retractable landing gear and a streamlined fuselage added to the aerodynamic efficiency of the aircraft. A single example was constructed for evaluation by both Boeing and the US Army (under the designation Y1C-18) but no mass production ensued, and the aircraft eventually joined Boeing's fleet on the San Francisco-Chicago air mail route from July 1931.

A second version was developed as the Model 221, with a fuselage stretched by 8 inches (20 cm) that sacrificed some of its cargo capacity to carry six passengers in an enclosed cabin, however the single pilot was in an open cockpit. This version first flew on 18 August 1930. Both the Model 200 and the Model 221 were eventually modified for transcontinental service as the Model 221A, with slight fuselage stretches to give both a cabin for eight passengers. These aircraft were flown on United Air Lines' Cheyenne-Chicago route.

The advanced design of the Monomail was hampered by the lack of suitable engine and propeller technology. By the time variable pitch propellers and more powerful engines were available, the design had been surpassed by multi engined aircraft, including Boeing's own 247.

Variants

;Model 200:mailplane (1 built);Model 221:mailplane with capacity for 6 passengers (1 built);Model 221A:Model 200 and 221 converted as 8-passenger airliners

pecifications (Model 221)

aircraft specification
plane or copter?=plane
jet or prop?=prop
crew= 1
capacity= 6
length main= 59 ft 1 in
length alt= 18 m
span main=41 ft 10 in
span alt= 12.75 m
height main=
height alt=
area main=
area alt=
airfoil=
empty weight main=
empty weight alt=
loaded weight main=
loaded weight alt=
useful load main=
useful load alt=
max takeoff weight main= 8,000 lb
max takeoff weight alt= 3,628.7 kg
more general=

engine (jet)=
type of jet=
number of jets=
thrust main=
thrust alt=
thrust original=
afterburning thrust main=
afterburning thrust alt=
engine (prop)=Pratt & Whitney Hornet B
type of prop=
number of props= 1
power main= 575 hp
power alt= 428.8 kW
power original=

max speed main= 158 mph
max speed alt= 254 km/h
cruise speed main= 135 mph
cruise speed alt= 217 km/h
stall speed main=
stall speed alt=
never exceed speed main=
never exceed speed alt=
range main= 575 mi
range alt= 925 km
ceiling main= 14,700 ft
ceiling alt= 4,480.5 m
climb rate main=
climb rate alt=
loading main=
loading alt=
thrust/weight=
power/mass main=
power/mass alt=
more performance=

ee also

aircontent
related=

similar aircraft=
*Lockheed Orion
*Northrop Alpha

lists=

see also=

References

[http://www.boeing.com/history/boeing/monomail.html Boeing History - Boeing Monomail Transport] Retrieved June 17, 2006.
*
*