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 A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...

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; the single pilot, however, sat in an open

cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a Pilot in command, pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the ...

. 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 A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...

technology. By the time

variable-pitch propeller Variable-pitch propeller can refer to: *Variable-pitch propeller (marine) *Variable-pitch propeller (aeronautics) In aeronautics, a variable-pitch propeller is a type of propeller (airscrew) with blades that can be rotated around their long a ...

s and more powerful engines were available, the design had been surpassed by multi-engined aircraft, including Boeing's own

247 __NOTOC__ Year 247 (Roman numerals, CCXLVII) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Philippus and Severus (or, less frequent ...

. However, many advancements of the Monomail were incorporated into the designs of the most advanced bomber and fighter aircraft of the early 1930s, the Boeing B-9 and the Model 248 (later developed into the P-26 Peashooter of the USAAC), respectively.

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 ;Model 231 :Planned lengthened version of Model 221, not built.

Operators

; * Boeing Air Transport * United Air Lines

Specifications (Model 221)

References

Boeing History - Boeing Monomail Transport
Retrieved June 17, 2006. * *

External links