The Boeing Model 200 Monomail was an American

mail plane A mail plane is an aircraft used for carrying mail. Aircraft that were purely mail planes existed almost exclusively prior to World War II. Because early aircraft were too underpowered to carry cargoes, and too costly to run any "economy class" ...

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 A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cant ...

wing. Retractable landing gear and a streamlined

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraf ...

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 San Francisco (; Spanish for " Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous in California and 17th ...

Chicago (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ...

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. 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 United Airlines, Inc. (commonly referred to as United), is a major American airline headquartered at the Willis Tower in Chicago, Illinois.

Cheyenne The Cheyenne ( ) are an Indigenous people of the Great Plains. Their Cheyenne language belongs to the Algonquian language family. Today, the Cheyenne people are split into two federally recognized nations: the Southern Cheyenne, who are enr ...

-Chicago route. The advanced design of the Monomail was hampered by the lack of suitable

engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ...

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 __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 The Boeing YB-9 was the first all-metal monoplane bomber aircraft designed for the United States Army Air Corps. The YB-9 was an enlarged alteration of Boeing's Model 200 Monomail commercial transport. Design and development In May 1930, Boei ...

and the Model 248 (later developed into the

P-26 Peashooter The Boeing P-26 "Peashooter" was the first American production all-metal fighter aircraft and the first pursuit monoplane to enter squadron service with the United States Army Air Corps. Designed and built by Boeing, the prototype first flew in ...

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 Airlines is the third largest airline in the world, with 86,852 employees (which includes the entire holding company United Airlines Holdings) and 721 aircraft. It was the brainchild of William Boeing and emerged from his consolidation of n ...

United Air Lines United Airlines, Inc. (commonly referred to as United), is a major American airline headquartered at the Willis Tower in Chicago, Illinois.

Specifications (Model 221)

References

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

External links