May 2005 
Volume 04, Issue 1 
Historical Perspective

Monomail defined future of flight 75 years ago


The year 1929 was one of great change for William Boeing and his young, flourishing company. After adding a successful airline, Boeing Air Transport, to his airplane firm, Boeing teamed with Fred Renschler, president of Pratt & Whitney, to merge their companies into United Aircraft and Transport Corporation. As the business expanded, the science of aviation was moving ahead at an amazing pace. Wood and fabric were giving way to metal frames and aluminum skin, and "streamlining" was the buzzword of airplane design.

Against this backdrop, Boeing Chief Engineer Charles "Monty" Monteith and the leadership of the Boeing Airplane Company had to make a crucial decision about the commercial airplane market's future. Major competitors Ford and Fokker were building bigger trimotor transports. But Monteith felt that a smaller, faster transport that took advantage of the latest technology might be the way to go. That airplane, known as the Monomail, made its first flight 75 years ago this month.

The smaller plane would be difficult to design and, like many new ideas, was not readily accepted. But doing the difficult and embracing new ideas followed the business philosophy of William Boeing. Earlier that year, he said in an interview: "We have already proved that science and hard work can lick what appear to be insurmountable difficulties."

Boeing continued: "I've tried to make the men around me feel, as I do, that we are embarked as pioneers upon a new science and industry in which our problems are so new and unusual that it behooves no one to dismiss any novel idea with the statement that 'it can't be done!' ... Our job is to keep everlastingly at research and experiment, to let no new improvement in flying and flying equipment pass us by."

With that, the decision was simple. Monteith and his staff forged ahead into new territory and brought together all of the latest technology possible into one airplane, which was given the Boeing model number 200 and named the Monomail.

While competitor Jack Northrop was developing a similar model in the Alpha, what made the Monomail unique was the combination of the latest ideas of aeronautical design. Among them: all-metal smooth-skin construction, a semimonocoque fuselage, low mounted cantilevered wings, an antidrag ring cowl and, most notably, the first recorded use of retractable landing gear.

Even with all of these new refinements, there were still conservative ideas and technologies that held back the Monomail. Pilots insisted on having an open cockpit. Also, pilot Eddie Allen discovered on the Monomail's first flight in 1930 that the airplane was so streamlined that the propeller angle or "pitch" needed to fly the plane at its best performance was not adequate to get the plane off the ground. That meant the propeller had to be set at a compromise pitch. Fortunately one of the firms belonging to William Boeing's corporation was propeller manufacturer Hamilton-Standard, which began developing the innovative variable-pitch propeller.

Despite these issues, the Monomail, powered by a single 575-horsepower Pratt & Whitney Hornet engine, had a top speed of 158 mph (254 kilometers per hour) and could carry 2,300 pounds (1,043 kilograms) of cargo. One Model 200 was built and was quickly followed by an improved version, the Model 221 Monomail, which had accommodations for eight passengers and 600 pounds (272 kilograms) of baggage. Both airplanes were used for extensive testing as well as revenue flights on the Boeing System.

However, no more were built. After gaining technological experience from the Monomails, Boeing designers developed even more-advanced aircraft including the B-9, the United States' first all-metal monoplane bomber, and the revolutionary Boeing Model 247, the world's first modern airliner. To the aviation world, the Monomail defined patterns that all future single engine monoplanes would follow, including those that would be the frontline fighters of World War II.


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