When Boeing revealed its Model 200 in 1930 and Monomail low set all metal cantilever wing monoplane with retractable landing gear along with a streamlined aerodynamic fuselage, it was a drastic departure from the traditional biplane configuration for a transport aircraft.
Although advanced in design, the Monomail was hampered by the lack of suitable engine and propeller technology. Photo © Boeing.
Although advanced in design, the 200 and Monomail was hampered by the lack of suitable engine and propeller technology and the design was soon surpassed by multi-engine aircraft. Only 221, most of which were later upgraded to 221 and 221A specifications, were used on mail routes in the USA were built before production was ceased in 1933. However, many of the 200's advance features were subsequently incorporated into the designs of the most advanced bomber and fighter aircraft built by Boeing in the early 1930s.
A second version was stretched by 8 inches (20 cm) designed to carry six passengers inside the fuselage. Photo © Air and Space Museum / commons.wikimedia.org
A single example was constructed for evaluation by the US Army but no orders were forthcoming. A second version was stretched by 8 inches (20 cm) designed to carry six passengers inside the fuselage. A third version, the Model 221A was a slightly stretched type able to carry eight passengers that were flown on United Air Lines' Cheyenne-Chicago route.
Specifications (Model 221)
Crew: One pilot
Capacity: 6 passengers
Length: 42 ft (13 m)
Wingspan: 59 ft (18 m)
Gross weight: 8,000 lb (3,629 kg)
Powerplant: 1 ◊ Pratt & Whitney R-1860 Hornet B radial engine, 575 hp (429 kW)
Maximum speed: 158 mph (254 km/h; 137 Kts)
Cruise speed: 135 mph (217 km/h; 117 Kts)
Range: 575 mi (500 nmi; 925 km)
Service ceiling: 14,700 ft (4,500 m)