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| Model 200 and 221 Monomail | |
|---|---|
.jpg) Model 221 | |
| General information | |
| Type | Airliner |
| National origin | United States |
| Manufacturer | Boeing |
| Status | Retired |
| Primary user | United Airlines |
| Number built | 1 Model 200 1 Model 221 |
| History | |
| First flight | 6 May 1930 |
| Retired | 1933 |
| Developed into | Boeing YB-9 |
TheBoeing Model 200 Monomail was an Americanmail plane of the early 1930s.
The aircraft marked a departure from the traditionalbiplane configuration for a transport aircraft, instead featuring a single, low set, all metalcantilever wing. Retractable landing gear and a streamlinedfuselage added to the aerodynamic efficiency of the aircraft. A single example was constructed for evaluation by both Boeing and the US Army (under the designationY1C-18) but no mass production ensued, and the aircraft eventually joined Boeing's fleet on theSan Francisco-Chicago air mail route from July 1931.
A second version was developed as theModel 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 opencockpit. This version first flew on 18 August 1930. Both theModel 200 and theModel 221 were eventually modified for transcontinental service as theModel 221A, with slight fuselage stretches to give both a cabin for eight passengers. These aircraft were flown onUnited Air Lines'Cheyenne-Chicago route.
The advanced design of the Monomail was hampered by the lack of suitableengine andpropeller technology. By the timevariable-pitch propellers and more powerful engines were available, the design had been surpassed by multi-engined aircraft, including Boeing's own247. However, many advancements of the Monomail were incorporated into the designs of the most advanced bomber and fighter aircraft of the early 1930s, theBoeing B-9 and the Model 248 (later developed into theP-26 Peashooter of the USAAC), respectively.
General characteristics
Performance
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