Boeing Monomail

The Boeing Model 200 Monomail was an American mail plane. It was built in the 1930s by Boeing. It flew for the first time on 6 May 1930.
The Boeing Monomail was a monoplane instead of a biplane. The wing was strong and did not need bracing. Its wheels could be ed. Only one plane was made for the US Army to look at. The plane eventually began to fly main from San Francisco to Chicago.
Another version was made, the Model 221. It was made longer by 8 inches. This meant it could carry passengers, but less cargo. This version first flew on 18 August 1930. 
There were no good engines for the Boeing Monomail to use. By the time good engines could be used, new planes had been made which were better than the Monomail. One of these was the Boeing 247.